nih-gov/www.ncbi.nlm.nih.gov/books/n/mlprobe/ml129/index.html
2025-03-17 02:05:34 +00:00

529 lines
No EOL
97 KiB
HTML
Raw Blame History

This file contains invisible Unicode characters

This file contains invisible Unicode characters that are indistinguishable to humans but may be processed differently by a computer. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head><meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<!-- AppResources meta begin -->
<meta name="paf-app-resources" content="" />
<script type="text/javascript">var ncbi_startTime = new Date();</script>
<!-- AppResources meta end -->
<!-- TemplateResources meta begin -->
<meta name="paf_template" content="" />
<!-- TemplateResources meta end -->
<!-- Logger begin -->
<meta name="ncbi_db" content="books" /><meta name="ncbi_pdid" content="book-part" /><meta name="ncbi_acc" content="NBK50691" /><meta name="ncbi_domain" content="mlprobe" /><meta name="ncbi_report" content="record" /><meta name="ncbi_type" content="fulltext" /><meta name="ncbi_objectid" content="" /><meta name="ncbi_pcid" content="/NBK50691/" /><meta name="ncbi_pagename" content="Discovery of the first mAChR 5 (M5) selective ligand, an M5 Positive Allosteric Modulator (PAM) - Probe Reports from the NIH Molecular Libraries Program - NCBI Bookshelf" /><meta name="ncbi_bookparttype" content="chapter" /><meta name="ncbi_app" content="bookshelf" />
<!-- Logger end -->
<title>Discovery of the first mAChR 5 (M5) selective ligand, an M5 Positive Allosteric Modulator (PAM) - Probe Reports from the NIH Molecular Libraries Program - NCBI Bookshelf</title>
<!-- AppResources external_resources begin -->
<link rel="stylesheet" href="/core/jig/1.15.2/css/jig.min.css" /><script type="text/javascript" src="/core/jig/1.15.2/js/jig.min.js"></script>
<!-- AppResources external_resources end -->
<!-- Page meta begin -->
<meta name="robots" content="INDEX,FOLLOW,NOARCHIVE" /><meta name="citation_inbook_title" content="Probe Reports from the NIH Molecular Libraries Program [Internet]" /><meta name="citation_title" content="Discovery of the first mAChR 5 (M5) selective ligand, an M5 Positive Allosteric Modulator (PAM)" /><meta name="citation_publisher" content="National Center for Biotechnology Information (US)" /><meta name="citation_date" content="2010/10/20" /><meta name="citation_author" content="Thomas M Bridges" /><meta name="citation_author" content="L Michelle Lewis" /><meta name="citation_author" content="C David Weaver" /><meta name="citation_author" content="Craig W Lindsley" /><meta name="citation_pmid" content="21433383" /><meta name="citation_fulltext_html_url" content="https://www.ncbi.nlm.nih.gov/books/NBK50691/" /><link rel="schema.DC" href="http://purl.org/DC/elements/1.0/" /><meta name="DC.Title" content="Discovery of the first mAChR 5 (M5) selective ligand, an M5 Positive Allosteric Modulator (PAM)" /><meta name="DC.Type" content="Text" /><meta name="DC.Publisher" content="National Center for Biotechnology Information (US)" /><meta name="DC.Contributor" content="Thomas M Bridges" /><meta name="DC.Contributor" content="L Michelle Lewis" /><meta name="DC.Contributor" content="C David Weaver" /><meta name="DC.Contributor" content="Craig W Lindsley" /><meta name="DC.Date" content="2010/10/20" /><meta name="DC.Identifier" content="https://www.ncbi.nlm.nih.gov/books/NBK50691/" /><meta name="description" content="Data from studies using muscarinic acetylcholine receptor (mAChR) subtype 5 knock-out (M5-KO) mice suggest that M5 is the sole mediator of ACh-induced vasodilation in the cerebral vasculature, and thereby, may have therapeutic relevance for cerebrovascular diseases or acute ischemic stroke. M5-KO mice have also been found to exhibit deficits in long-term potentiation (LTP) at the hippocampal mossy fiber-CA3 synapse and show deficits in hippocampal-dependent behavioral cognitive tests. In light of these and other related findings, activation of M5 has been suggested as a potential target for treatment of Alzheimer's disease, perhaps in combination with M1 activation. However, due to the scarcity of selective compounds, a detailed understanding of the precise neurobiological roles of each subtype in various central nervous system (CNS) disorders has thus remained challenging. Recently, a number of novel highly subtype-selective allosteric ligands for M1 and M4 have emerged from functional cell-based screening efforts. However, no ligands have been reported to date as being highly M5-preferring or selective. Relative to the other mAChRs, little is known about M5, which is expressed at very low levels in the CNS and peripheral tissues. The currently identified probe ML129 (CID-42633508) possesses unprecedented M5 selectivity versus M1, M2, M3 and M4, as well as selectivity against a large panel of GPCRs, ion channels and transporters. The probe is not centrally penetrant, and so would need to be administered i.c.v. to study the role of central M5 activation in vivo. The probe also displays reasonable solubility in acceptable vehicles. Thus, ML129 can be used for in vitro molecular pharmacology and electrophysiology experiments to study, for the first time, the role of selective M5 receptor activation." /><meta name="og:title" content="Discovery of the first mAChR 5 (M5) selective ligand, an M5 Positive Allosteric Modulator (PAM)" /><meta name="og:type" content="book" /><meta name="og:description" content="Data from studies using muscarinic acetylcholine receptor (mAChR) subtype 5 knock-out (M5-KO) mice suggest that M5 is the sole mediator of ACh-induced vasodilation in the cerebral vasculature, and thereby, may have therapeutic relevance for cerebrovascular diseases or acute ischemic stroke. M5-KO mice have also been found to exhibit deficits in long-term potentiation (LTP) at the hippocampal mossy fiber-CA3 synapse and show deficits in hippocampal-dependent behavioral cognitive tests. In light of these and other related findings, activation of M5 has been suggested as a potential target for treatment of Alzheimer's disease, perhaps in combination with M1 activation. However, due to the scarcity of selective compounds, a detailed understanding of the precise neurobiological roles of each subtype in various central nervous system (CNS) disorders has thus remained challenging. Recently, a number of novel highly subtype-selective allosteric ligands for M1 and M4 have emerged from functional cell-based screening efforts. However, no ligands have been reported to date as being highly M5-preferring or selective. Relative to the other mAChRs, little is known about M5, which is expressed at very low levels in the CNS and peripheral tissues. The currently identified probe ML129 (CID-42633508) possesses unprecedented M5 selectivity versus M1, M2, M3 and M4, as well as selectivity against a large panel of GPCRs, ion channels and transporters. The probe is not centrally penetrant, and so would need to be administered i.c.v. to study the role of central M5 activation in vivo. The probe also displays reasonable solubility in acceptable vehicles. Thus, ML129 can be used for in vitro molecular pharmacology and electrophysiology experiments to study, for the first time, the role of selective M5 receptor activation." /><meta name="og:url" content="https://www.ncbi.nlm.nih.gov/books/NBK50691/" /><meta name="og:site_name" content="NCBI Bookshelf" /><meta name="og:image" content="https://www.ncbi.nlm.nih.gov/corehtml/pmc/pmcgifs/bookshelf/thumbs/th-mlprobe-lrg.png" /><meta name="twitter:card" content="summary" /><meta name="twitter:site" content="@ncbibooks" /><meta name="bk-non-canon-loc" content="/books/n/mlprobe/ml129/" /><link rel="canonical" href="https://www.ncbi.nlm.nih.gov/books/NBK50691/" /><link rel="stylesheet" href="/corehtml/pmc/css/figpopup.css" type="text/css" media="screen" /><link rel="stylesheet" href="/corehtml/pmc/css/bookshelf/2.26/css/books.min.css" type="text/css" /><link rel="stylesheet" href="/corehtml/pmc/css/bookshelf/2.26/css/books_print.min.css" type="text/css" media="print" /><style type="text/css">p a.figpopup{display:inline !important} .bk_tt {font-family: monospace} .first-line-outdent .bk_ref {display: inline} .body-content h2, .body-content .h2 {border-bottom: 1px solid #97B0C8} .body-content h2.inline {border-bottom: none} a.page-toc-label , .jig-ncbismoothscroll a {text-decoration:none;border:0 !important} .temp-labeled-list .graphic {display:inline-block !important} .temp-labeled-list img{width:100%}</style><script type="text/javascript" src="/corehtml/pmc/js/jquery.hoverIntent.min.js"> </script><script type="text/javascript" src="/corehtml/pmc/js/common.min.js?_=3.18"> </script><script type="text/javascript" src="/corehtml/pmc/js/large-obj-scrollbars.min.js"> </script><script type="text/javascript">window.name="mainwindow";</script><script type="text/javascript" src="/corehtml/pmc/js/bookshelf/2.26/book-toc.min.js"> </script><script type="text/javascript" src="/corehtml/pmc/js/bookshelf/2.26/books.min.js"> </script><meta name="book-collection" content="NONE" />
<!-- Page meta end -->
<link rel="shortcut icon" href="//www.ncbi.nlm.nih.gov/favicon.ico" /><meta name="ncbi_phid" content="CE8E02947D65D2210000000000F400D7.m_13" />
<meta name='referrer' content='origin-when-cross-origin'/><link type="text/css" rel="stylesheet" href="//static.pubmed.gov/portal/portal3rc.fcgi/4216699/css/3852956/3985586/3808861/4121862/3974050/3917732/251717/4216701/14534/45193/4113719/3849091/3984811/3751656/4033350/3840896/3577051/3852958/4008682/4207974/4206132/4062871/12930/3964959/3854974/36029/4128070/9685/3549676/3609192/3609193/3609213/3395586.css" /><link type="text/css" rel="stylesheet" href="//static.pubmed.gov/portal/portal3rc.fcgi/4216699/css/3411343/3882866.css" media="print" /></head>
<body class="book-part">
<div class="grid">
<div class="col twelve_col nomargin shadow">
<!-- System messages like service outage or JS required; this is handled by the TemplateResources portlet -->
<div class="sysmessages">
<noscript>
<p class="nojs">
<strong>Warning:</strong>
The NCBI web site requires JavaScript to function.
<a href="/guide/browsers/#enablejs" title="Learn how to enable JavaScript" target="_blank">more...</a>
</p>
</noscript>
</div>
<!--/.sysmessage-->
<div class="wrap">
<div class="page">
<div class="top">
<div id="universal_header">
<section class="usa-banner">
<div class="usa-accordion">
<header class="usa-banner-header">
<div class="usa-grid usa-banner-inner">
<img src="https://www.ncbi.nlm.nih.gov/coreutils/uswds/img/favicons/favicon-57.png" alt="U.S. flag" />
<p>An official website of the United States government</p>
<button class="non-usa-accordion-button usa-banner-button" aria-expanded="false" aria-controls="gov-banner-top" type="button">
<span class="usa-banner-button-text">Here's how you know</span>
</button>
</div>
</header>
<div class="usa-banner-content usa-grid usa-accordion-content" id="gov-banner-top" aria-hidden="true">
<div class="usa-banner-guidance-gov usa-width-one-half">
<img class="usa-banner-icon usa-media_block-img" src="https://www.ncbi.nlm.nih.gov/coreutils/uswds/img/icon-dot-gov.svg" alt="Dot gov" />
<div class="usa-media_block-body">
<p>
<strong>The .gov means it's official.</strong>
<br />
Federal government websites often end in .gov or .mil. Before
sharing sensitive information, make sure you're on a federal
government site.
</p>
</div>
</div>
<div class="usa-banner-guidance-ssl usa-width-one-half">
<img class="usa-banner-icon usa-media_block-img" src="https://www.ncbi.nlm.nih.gov/coreutils/uswds/img/icon-https.svg" alt="Https" />
<div class="usa-media_block-body">
<p>
<strong>The site is secure.</strong>
<br />
The <strong>https://</strong> ensures that you are connecting to the
official website and that any information you provide is encrypted
and transmitted securely.
</p>
</div>
</div>
</div>
</div>
</section>
<div class="usa-overlay"></div>
<header class="ncbi-header" role="banner" data-section="Header">
<div class="usa-grid">
<div class="usa-width-one-whole">
<div class="ncbi-header__logo">
<a href="/" class="logo" aria-label="NCBI Logo" data-ga-action="click_image" data-ga-label="NIH NLM Logo">
<img src="https://www.ncbi.nlm.nih.gov/coreutils/nwds/img/logos/AgencyLogo.svg" alt="NIH NLM Logo" />
</a>
</div>
<div class="ncbi-header__account">
<a id="account_login" href="https://account.ncbi.nlm.nih.gov" class="usa-button header-button" style="display:none" data-ga-action="open_menu" data-ga-label="account_menu">Log in</a>
<button id="account_info" class="header-button" style="display:none" aria-controls="account_popup" type="button">
<span class="fa fa-user" aria-hidden="true">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" width="20px" height="20px">
<g style="fill: #fff">
<ellipse cx="12" cy="8" rx="5" ry="6"></ellipse>
<path d="M21.8,19.1c-0.9-1.8-2.6-3.3-4.8-4.2c-0.6-0.2-1.3-0.2-1.8,0.1c-1,0.6-2,0.9-3.2,0.9s-2.2-0.3-3.2-0.9 C8.3,14.8,7.6,14.7,7,15c-2.2,0.9-3.9,2.4-4.8,4.2C1.5,20.5,2.6,22,4.1,22h15.8C21.4,22,22.5,20.5,21.8,19.1z"></path>
</g>
</svg>
</span>
<span class="username desktop-only" aria-hidden="true" id="uname_short"></span>
<span class="sr-only">Show account info</span>
</button>
</div>
<div class="ncbi-popup-anchor">
<div class="ncbi-popup account-popup" id="account_popup" aria-hidden="true">
<div class="ncbi-popup-head">
<button class="ncbi-close-button" data-ga-action="close_menu" data-ga-label="account_menu" type="button">
<span class="fa fa-times">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 48 48" width="24px" height="24px">
<path d="M38 12.83l-2.83-2.83-11.17 11.17-11.17-11.17-2.83 2.83 11.17 11.17-11.17 11.17 2.83 2.83 11.17-11.17 11.17 11.17 2.83-2.83-11.17-11.17z"></path>
</svg>
</span>
<span class="usa-sr-only">Close</span></button>
<h4>Account</h4>
</div>
<div class="account-user-info">
Logged in as:<br />
<b><span class="username" id="uname_long">username</span></b>
</div>
<div class="account-links">
<ul class="usa-unstyled-list">
<li><a id="account_myncbi" href="/myncbi/" class="set-base-url" data-ga-action="click_menu_item" data-ga-label="account_myncbi">Dashboard</a></li>
<li><a id="account_pubs" href="/myncbi/collections/bibliography/" class="set-base-url" data-ga-action="click_menu_item" data-ga-label="account_pubs">Publications</a></li>
<li><a id="account_settings" href="/account/settings/" class="set-base-url" data-ga-action="click_menu_item" data-ga-label="account_settings">Account settings</a></li>
<li><a id="account_logout" href="/account/signout/" class="set-base-url" data-ga-action="click_menu_item" data-ga-label="account_logout">Log out</a></li>
</ul>
</div>
</div>
</div>
</div>
</div>
</header>
<div role="navigation" aria-label="access keys">
<a id="nws_header_accesskey_0" href="https://www.ncbi.nlm.nih.gov/guide/browsers/#ncbi_accesskeys" class="usa-sr-only" accesskey="0" tabindex="-1">Access keys</a>
<a id="nws_header_accesskey_1" href="https://www.ncbi.nlm.nih.gov" class="usa-sr-only" accesskey="1" tabindex="-1">NCBI Homepage</a>
<a id="nws_header_accesskey_2" href="/myncbi/" class="set-base-url usa-sr-only" accesskey="2" tabindex="-1">MyNCBI Homepage</a>
<a id="nws_header_accesskey_3" href="#maincontent" class="usa-sr-only" accesskey="3" tabindex="-1">Main Content</a>
<a id="nws_header_accesskey_4" href="#" class="usa-sr-only" accesskey="4" tabindex="-1">Main Navigation</a>
</div>
<section data-section="Alerts">
<div class="ncbi-alerts-placeholder"></div>
</section>
</div>
<div class="header">
<div class="res_logo"><h1 class="res_name"><a href="/books/" title="Bookshelf home">Bookshelf</a></h1><h2 class="res_tagline"></h2></div>
<div class="search"><form method="get" action="/books/"><div class="search_form"><label for="database" class="offscreen_noflow">Search database</label><select id="database"><optgroup label="Recent"><option value="books" selected="selected" data-ac_dict="bookshelf-search">Books</option><option value="pubmed">PubMed</option><option value="clinvar">ClinVar</option><option value="refseq" class="last">RefSeq</option></optgroup><optgroup label="All"><option value="gquery">All Databases</option><option value="assembly">Assembly</option><option value="biocollections">Biocollections</option><option value="bioproject">BioProject</option><option value="biosample">BioSample</option><option value="books" data-ac_dict="bookshelf-search">Books</option><option value="clinvar">ClinVar</option><option value="cdd">Conserved Domains</option><option value="gap">dbGaP</option><option value="dbvar">dbVar</option><option value="gene">Gene</option><option value="genome">Genome</option><option value="gds">GEO DataSets</option><option value="geoprofiles">GEO Profiles</option><option value="gtr">GTR</option><option value="ipg">Identical Protein Groups</option><option value="medgen">MedGen</option><option value="mesh">MeSH</option><option value="nlmcatalog">NLM Catalog</option><option value="nuccore">Nucleotide</option><option value="omim">OMIM</option><option value="pmc">PMC</option><option value="protein">Protein</option><option value="proteinclusters">Protein Clusters</option><option value="protfam">Protein Family Models</option><option value="pcassay">PubChem BioAssay</option><option value="pccompound">PubChem Compound</option><option value="pcsubstance">PubChem Substance</option><option value="pubmed">PubMed</option><option value="snp">SNP</option><option value="sra">SRA</option><option value="structure">Structure</option><option value="taxonomy">Taxonomy</option><option value="toolkit">ToolKit</option><option value="toolkitall">ToolKitAll</option><option value="toolkitbookgh">ToolKitBookgh</option></optgroup></select><div class="nowrap"><label for="term" class="offscreen_noflow" accesskey="/">Search term</label><div class="nowrap"><input type="text" name="term" id="term" title="Search Books. Use up and down arrows to choose an item from the autocomplete." value="" class="jig-ncbiclearbutton jig-ncbiautocomplete" data-jigconfig="dictionary:'bookshelf-search',disableUrl:'NcbiSearchBarAutoComplCtrl'" autocomplete="off" data-sbconfig="ds:'no',pjs:'no',afs:'no'" /></div><button id="search" type="submit" class="button_search nowrap" cmd="go">Search</button></div></div></form><ul class="searchlinks inline_list"><li>
<a href="/books/browse/">Browse Titles</a>
</li><li>
<a href="/books/advanced/">Advanced</a>
</li><li class="help">
<a href="/books/NBK3833/">Help</a>
</li><li class="disclaimer">
<a target="_blank" data-ga-category="literature_resources" data-ga-action="link_click" data-ga-label="disclaimer_link" href="https://www.ncbi.nlm.nih.gov/books/about/disclaimer/">Disclaimer</a>
</li></ul></div>
</div>
<!--<component id="Page" label="headcontent"/>-->
</div>
<div class="content">
<!-- site messages -->
<!-- Custom content 1 -->
<div class="col1">
</div>
<div class="container">
<div id="maincontent" class="content eight_col col">
<!-- Custom content in the left column above book nav -->
<div class="col2">
</div>
<!-- Book content -->
<!-- Custom content between navigation and content -->
<div class="col3">
</div>
<div class="document">
<div class="pre-content"><div><div class="bk_prnt"><p class="small">NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.</p><p>Probe Reports from the NIH Molecular Libraries Program [Internet]. Bethesda (MD): National Center for Biotechnology Information (US); 2010-. </p></div><div class="iconblock clearfix whole_rhythm no_top_margin bk_noprnt"><a class="img_link icnblk_img" title="Table of Contents Page" href="/books/n/mlprobe/"><img class="source-thumb" src="/corehtml/pmc/pmcgifs/bookshelf/thumbs/th-mlprobe-lrg.png" alt="Cover of Probe Reports from the NIH Molecular Libraries Program" height="100px" width="80px" /></a><div class="icnblk_cntnt eight_col"><h2>Probe Reports from the NIH Molecular Libraries Program [Internet].</h2><a data-jig="ncbitoggler" href="#__NBK50691_dtls__">Show details</a><div style="display:none" class="ui-widget" id="__NBK50691_dtls__"><div>Bethesda (MD): National Center for Biotechnology Information (US); 2010-.</div></div><div class="half_rhythm"><ul class="inline_list"><li style="margin-right:1em"><a class="bk_cntns" href="/books/n/mlprobe/">Contents</a></li></ul></div><div class="bk_noprnt"><form method="get" action="/books/n/mlprobe/" id="bk_srch"><div class="bk_search"><label for="bk_term" class="offscreen_noflow">Search term</label><input type="text" title="Search this book" id="bk_term" name="term" value="" data-jig="ncbiclearbutton" /> <input type="submit" class="jig-ncbibutton" value="Search this book" submit="false" style="padding: 0.1em 0.4em;" /></div></form></div></div><div class="icnblk_cntnt two_col"><div class="pagination bk_noprnt"><a class="active page_link prev" href="/books/n/mlprobe/ml130/" title="Previous page in this title">&lt; Prev</a><a class="active page_link next" href="/books/n/mlprobe/ml128/" title="Next page in this title">Next &gt;</a></div></div></div></div></div>
<div class="main-content lit-style" itemscope="itemscope" itemtype="http://schema.org/CreativeWork"><div class="meta-content fm-sec"><h1 id="_NBK50691_"><span class="title" itemprop="name">Discovery of the first mAChR 5 (M5) selective ligand, an M5 Positive Allosteric Modulator (PAM)</span></h1><p class="contrib-group"><span itemprop="author">Thomas M Bridges</span>, <span itemprop="author">L Michelle Lewis</span>, <span itemprop="author">C David Weaver</span>, and <span itemprop="author">Craig W Lindsley</span>.</p><a data-jig="ncbitoggler" href="#__NBK50691_ai__" style="border:0;text-decoration:none">Author Information and Affiliations</a><div style="display:none" class="ui-widget" id="__NBK50691_ai__"><p class="contrib-group"><h4>Authors</h4><span itemprop="author">Thomas M Bridges</span>, <span itemprop="author">L Michelle Lewis</span>, <span itemprop="author">C David Weaver</span>, and <span itemprop="author">Craig W Lindsley</span><sup>1</sup>.</p><h4>Contact</h4><div class="affiliation"><sup>1</sup> <span class="email-label">Email: </span><a href="mailto:dev@null" data-email="ude.tlibrednav@yelsdnil.giarc" class="oemail">ude.tlibrednav@yelsdnil.giarc</a></div></div><p class="small">Received: <span itemprop="datePublished">December 18, 2009</span>; Last Update: <span itemprop="dateModified">October 20, 2010</span>.</p></div><div class="jig-ncbiinpagenav body-content whole_rhythm" data-jigconfig="allHeadingLevels: ['h2'],smoothScroll: false" itemprop="text"><div id="_abs_rndgid_" itemprop="description"><p>Data from studies using muscarinic acetylcholine receptor (mAChR) subtype 5 knock-out (M5-KO) mice suggest that M5 is the sole mediator of ACh-induced vasodilation in the cerebral vasculature, and thereby, may have therapeutic relevance for cerebrovascular diseases or acute ischemic stroke. M5-KO mice have also been found to exhibit deficits in long-term potentiation (LTP) at the hippocampal mossy fiber-CA3 synapse and show deficits in hippocampal-dependent behavioral cognitive tests. In light of these and other related findings, activation of M5 has been suggested as a potential target for treatment of Alzheimer's disease, perhaps in combination with M1 activation. However, due to the scarcity of selective compounds, a detailed understanding of the precise neurobiological roles of each subtype in various central nervous system (CNS) disorders has thus remained challenging. Recently, a number of novel highly subtype-selective allosteric ligands for M1 and M4 have emerged from functional cell-based screening efforts. However, no ligands have been reported to date as being highly M5-preferring or selective. Relative to the other mAChRs, little is known about M5, which is expressed at very low levels in the CNS and peripheral tissues. The currently identified probe ML129 (CID-42633508) possesses unprecedented M5 selectivity versus M1, M2, M3 and M4, as well as selectivity against a large panel of GPCRs, ion channels and transporters. The probe is not centrally penetrant, and so would need to be administered i.c.v. to study the role of central M5 activation in vivo. The probe also displays reasonable solubility in acceptable vehicles. Thus, ML129 can be used for in vitro molecular pharmacology and electrophysiology experiments to study, for the first time, the role of selective M5 receptor activation.</p></div><div class="h2"></div><p><b>Assigned Assay Grant #:</b> MH077607-01</p><p><b>Screening Center Name &#x00026; PI:</b> Vanderbilt Screening Center for GPCRs, Ion Channels and Transporters, C. David Weaver</p><p><b>Chemistry Center Name &#x00026; PI:</b> Vanderbilt Specialized Chemistry Center for Accelerated Probe Development, Craig W. Lindsley</p><p><b>Assay Submitter &#x00026; Institution:</b> P. Jeffrey Conn, Vanderbilt University</p><p><b>PubChem Summary Bioassay Identifier (AID):</b>
<a href="https://pubchem.ncbi.nlm.nih.gov/bioassay/2416" ref="pagearea=body&amp;targetsite=entrez&amp;targetcat=link&amp;targettype=pubchem">AID-2416</a></p><div id="ml129.s2"><h2 id="_ml129_s2_">Probe Structure &#x00026; Characteristics</h2><p>1-(4-methoxybenzyl)-5-(trifluoromethoxy)indoline-2,3-dione MW = 351.2, logP = 3.6, tPSA = 55.8</p><div id="ml129.fu1" class="figure"><div class="graphic"><img src="/books/NBK50691/bin/ml129fu1.jpg" alt="Image ml129fu1" /></div></div><div id="ml129.tu1" class="table"><p class="large-table-link" style="display:none"><span class="right"><a href="/books/NBK50691/table/ml129.tu1/?report=objectonly" target="object">View in own window</a></span></p><div class="large_tbl" id="__ml129.tu1_lrgtbl__"><table><thead><tr><th id="hd_h_ml129.tu1_1_1_1_1" rowspan="1" colspan="1" style="text-align:center;vertical-align:top;">CID/ML#</th><th id="hd_h_ml129.tu1_1_1_1_2" rowspan="1" colspan="1" style="text-align:center;vertical-align:top;">Target Name</th><th id="hd_h_ml129.tu1_1_1_1_3" rowspan="1" colspan="1" style="text-align:center;vertical-align:top;">IC50/EC50 (nM) [SID, AID]</th><th id="hd_h_ml129.tu1_1_1_1_4" rowspan="1" colspan="1" style="text-align:center;vertical-align:top;">Anti-target Name(s)</th><th id="hd_h_ml129.tu1_1_1_1_5" rowspan="1" colspan="1" style="text-align:center;vertical-align:top;">IC50/EC50 (&#x003bc;M) [SID, AID]</th><th id="hd_h_ml129.tu1_1_1_1_6" rowspan="1" colspan="1" style="text-align:center;vertical-align:top;">Selectivity</th><th id="hd_h_ml129.tu1_1_1_1_7" rowspan="1" colspan="1" style="text-align:center;vertical-align:top;">Secondary Assay(s) Name: IC50/EC50 (nM) [SID, AID]</th></tr></thead><tbody><tr><td headers="hd_h_ml129.tu1_1_1_1_1" rowspan="1" colspan="1" style="text-align:center;vertical-align:top;">CID-42633508<br /><a href="/pcsubstance/?term=ML129[synonym]" ref="pagearea=body&amp;targetsite=entrez&amp;targetcat=term&amp;targettype=pubchem">ML129</a></td><td headers="hd_h_ml129.tu1_1_1_1_2" rowspan="1" colspan="1" style="text-align:center;vertical-align:top;">M5</td><td headers="hd_h_ml129.tu1_1_1_1_3" rowspan="1" colspan="1" style="text-align:center;vertical-align:top;">1,100 [<a href="https://pubchem.ncbi.nlm.nih.gov/substance/85285486" ref="pagearea=body&amp;targetsite=entrez&amp;targetcat=link&amp;targettype=pubchem">SID-85285486</a>, <a href="https://pubchem.ncbi.nlm.nih.gov/bioassay/2204" ref="pagearea=body&amp;targetsite=entrez&amp;targetcat=link&amp;targettype=pubchem">AID-2204</a> M56]</td><td headers="hd_h_ml129.tu1_1_1_1_4" rowspan="1" colspan="1" style="text-align:center;vertical-align:top;">M1, M2, M3, M4<br /><br />MDS Pharma</td><td headers="hd_h_ml129.tu1_1_1_1_5" rowspan="1" colspan="1" style="text-align:center;vertical-align:top;">&#x0003e; 30 &#x003bc;M [<a href="https://pubchem.ncbi.nlm.nih.gov/substance/85285486" ref="pagearea=body&amp;targetsite=entrez&amp;targetcat=link&amp;targettype=pubchem">SID-85285486</a>, <a href="https://pubchem.ncbi.nlm.nih.gov/bioassay/2204" ref="pagearea=body&amp;targetsite=entrez&amp;targetcat=link&amp;targettype=pubchem">AID-2204</a>, <a href="https://pubchem.ncbi.nlm.nih.gov/bioassay/2198" ref="pagearea=body&amp;targetsite=entrez&amp;targetcat=link&amp;targettype=pubchem">AID-2198</a>]</td><td headers="hd_h_ml129.tu1_1_1_1_6" rowspan="1" colspan="1" style="text-align:center;vertical-align:top;">&#x0003e;30</td><td headers="hd_h_ml129.tu1_1_1_1_7" rowspan="1" colspan="1" style="text-align:center;vertical-align:top;">[<sup>3</sup>H]-NMS Binding<br /><br />(&#x0003e; 30
&#x003bc;M) ACh Fold-shift (&#x0003e; 14-fold)<br /><br />[<a href="https://pubchem.ncbi.nlm.nih.gov/substance/85285486" ref="pagearea=body&amp;targetsite=entrez&amp;targetcat=link&amp;targettype=pubchem">SID-85285486</a>, <a href="https://pubchem.ncbi.nlm.nih.gov/bioassay/2194" ref="pagearea=body&amp;targetsite=entrez&amp;targetcat=link&amp;targettype=pubchem">AID-2194</a>, <a href="https://pubchem.ncbi.nlm.nih.gov/bioassay/2192" ref="pagearea=body&amp;targetsite=entrez&amp;targetcat=link&amp;targettype=pubchem">AID-2192</a>,
<a href="https://pubchem.ncbi.nlm.nih.gov/bioassay/2186" ref="pagearea=body&amp;targetsite=entrez&amp;targetcat=link&amp;targettype=pubchem">AID-2186</a>]</td></tr></tbody></table></div></div></div><div id="ml129.s3"><h2 id="_ml129_s3_">Recommendations for the scientific use of this probe</h2><p>This probe (CID 42633508) can be used for <i>in vitro</i> molecular pharmacology and
electrophysiology experiments to study, for the first time, the role of selective M5 receptor
activation. This probe possesses unprecedented selectivity versus M1, M2, M3 and M4, as well as a large panel of GPCRs, ion channels and transporters. CID 42633508 is not centrally penetrant, and so would need to be administered i.c.v. to study the role of central M5 activation <i>in vivo.</i> CID 42633508 also displays reasonable solubility in acceptable vehicles (&#x0003e;5 mg/mL) in 20% &#x003b2;-cyclodextrin and &#x0003e;100 &#x003bc;M in DMSO.</p><div id="ml129.s4"><h3>Specific AIM</h3><p>To identify small molecule positive allosteric modulators (PAMs) and/or allosteric agonists of the M1 muscarinic acetylcholine receptor that are cell permeable, possess submicromolar potency and show greater than 10-fold selectivity over the other mAChRs (M1, M2, M3 and M4) employing a functional HTS approach. Out of this effort aimed at M1, which afforded a highly selective M1 antagonist (CID 24768606) and a highly selective M1 allosteric agonist (CID 25010775), we also identified and optimized the first M5 ligand, an M5 PAM described herein. Another MLSCN screening effort identified a highly selective M4 PAM (CID 864492); thus, a toolkit containing highly selective mAChR ligands are available from the MLPCN to study individual mAChR function.</p></div><div id="ml129.s5"><h3>Significance</h3><p>The five cloned muscarinic acetylcholine receptor subtypes (mAChR1-5 or M1-5) are known to play
highly important and diverse roles in many basic physiological processes. (<a class="bk_pop" href="#ml129.r1" data-bk-pop-others="ml129.r2 ml129.r3">1&#x02013;3</a>) Correspondingly, muscarinic agonists and
antagonists targeting one or more subtypes have been used preclinically and clinically for research
and treatment of a wide range of pathologies. (<a class="bk_pop" href="#ml129.r3">3</a>,<a class="bk_pop" href="#ml129.r4">4</a>) Based on the high sequence homology of the mAChRs across
subtypes, and particularly within the orthosteric acetylcholine (ACh) binding site, discovery of
truly subtype-selective compounds has proven historically difficult. Due to the scarcity of
selective compounds, a detailed understanding of the precise roles of each subtype in neurobiology
and in various central nervous system (CNS) disorders has thus remained challenging (<a class="bk_pop" href="#ml129.r3">3</a>,<a class="bk_pop" href="#ml129.r4">4</a>). Recently, a
number of novel highly subtype-selective allosteric ligands for M1 and M4 have emerged from
functional cell-based screening efforts (<a class="bk_pop" href="#ml129.r5">5</a>,<a class="bk_pop" href="#ml129.r6">6</a>). However, no ligands have been reported to date as being highly M5-preferring or selective. Relative to the other mAChRs, little is known about M5, which is expressed at very low levels in the CNS and peripheral tissues (<a class="bk_pop" href="#ml129.r2" data-bk-pop-others="ml129.r3 ml129.r4">2&#x02013;4</a>).</p></div><div id="ml129.s6"><h3>Rationale</h3><p>Data from studies using mAChR5 knock-out (M5-KO) mice suggest that M5 is the sole mediator of
ACh-induced vasodilation in the cerebral vasculature and thereby may have therapeutic relevance for
cerebrovascular diseases or acute ischemic stroke (<a class="bk_pop" href="#ml129.r7">7</a>,<a class="bk_pop" href="#ml129.r8">8</a>). M5-KO mice have also been
found to exhibit deficits in long-term potentiation (LTP) at the hippocampal mossy fiber-CA3 synapse
and show deficits in hippocampal-dependent behavioral cognitive tests (<a class="bk_pop" href="#ml129.r8">8</a>). In light of these and related findings, activation of M5 has been
suggested as a potential target for treatment of Alzheimer&#x02019;s disease, perhaps in combination
with M1 activation (<a class="bk_pop" href="#ml129.r9">9</a>). Consistent with the putative
post-synaptic localization of M5 in the ventral tegmental area (VTA), other M5-KO data suggest this
subtype plays an important role in regulation of mesolimbic dopamine transmission (<a class="bk_pop" href="#ml129.r3">3</a>,<a class="bk_pop" href="#ml129.r9">9</a>). Indeed,
M5-KO mice exhibit decreased reward responses to morphine, decreased self-administration of cocaine,
and less pronounced drug withdrawal symptoms, suggesting that M5 antagonists or negative modulators
may have therapeutic value in treatment of illicit drug addiction (<a class="bk_pop" href="#ml129.r9" data-bk-pop-others="ml129.r10 ml129.r11">9&#x02013;11</a>). Further pharmacological exploration of these and related hypotheses greatly depends on the discovery of novel M5-preferring or selective small molecule tools.</p></div></div><div id="ml129.s7"><h2 id="_ml129_s7_">Screening Center Information: Assay Implementation and Screening</h2><div id="ml129.s8"><h3>PubChem Bioassay Name</h3><p>Discovery of Novel Allosteric Modulators of the M1 Muscarinic Receptor: Agonist</p></div><div id="ml129.s9"><h3>List of PubChem bioassay identifiers generated for this screening project (AIDs)</h3><p><b><a href="https://pubchem.ncbi.nlm.nih.gov/bioassay/2206" ref="pagearea=body&amp;targetsite=entrez&amp;targetcat=link&amp;targettype=pubchem">AID-2206</a>, <a href="https://pubchem.ncbi.nlm.nih.gov/bioassay/2204" ref="pagearea=body&amp;targetsite=entrez&amp;targetcat=link&amp;targettype=pubchem">AID-2204</a>, <a href="https://pubchem.ncbi.nlm.nih.gov/bioassay/2198" ref="pagearea=body&amp;targetsite=entrez&amp;targetcat=link&amp;targettype=pubchem">AID-2198</a>, <a href="https://pubchem.ncbi.nlm.nih.gov/bioassay/2194" ref="pagearea=body&amp;targetsite=entrez&amp;targetcat=link&amp;targettype=pubchem">AID-2194</a>, <a href="https://pubchem.ncbi.nlm.nih.gov/bioassay/2192" ref="pagearea=body&amp;targetsite=entrez&amp;targetcat=link&amp;targettype=pubchem">AID-2192</a>, <a href="https://pubchem.ncbi.nlm.nih.gov/bioassay/2186" ref="pagearea=body&amp;targetsite=entrez&amp;targetcat=link&amp;targettype=pubchem">AID-2186</a>, <a href="https://pubchem.ncbi.nlm.nih.gov/bioassay/2416" ref="pagearea=body&amp;targetsite=entrez&amp;targetcat=link&amp;targettype=pubchem">AID-2416</a>, <a href="https://pubchem.ncbi.nlm.nih.gov/bioassay/626" ref="pagearea=body&amp;targetsite=entrez&amp;targetcat=link&amp;targettype=pubchem">AID-626</a></b></p></div><div id="ml129.s10"><h3>PubChem Primary Assay Description</h3><p>Chinese hamster ovary (CHO K1) cells stably expressing rat (r)M1 were purchased from the American Type Culture Collection (ATCC, Manassas, VA) and cultured according to their recommendations. CHO cells stably expressing human (h) M2, hM3, and hM5 were generously provided by A. Levey (Emory University, Atlanta, GA); rM4 cDNA provided by T. I. Bonner (National Institutes of Health, Bethesda, MD) was used to stably transfect CHO-K1 cells purchased from the ATCC using Lipofectamine 2000. To make stable hM2 and rM4 cell lines for use in calcium mobilization assays, cell lines were cotransfected with a chimeric G protein (G<sub>qi5</sub>) using Lipofectamine 2000. hM2, hM3, and hM5 cells were grown in Ham&#x02019;s F-12 medium containing 10% heat-inactivated fetal bovine serum, 2 mM GlutaMax I, 20 mM HEPES, and 50 &#x003bc;g/mL G418 sulfate. hM2-Gqi5 cells were grown in the same medium supplemented with 500 &#x003bc;g/mL hygromycin B. Stable rM4 cells were grown in Dulbecco&#x02019;s modified Eagle&#x02019;s medium containing 10% heat-inactivated fetal bovine serum, 2 mM GlutaMax I, 1 mM sodium pyruvate, 0.1 mM nonessential amino acids, 20 mM HEPES, and 400 &#x003bc;g/mL G418 sulfate; rM4-G<sub>qi5</sub> cells were grown in the same medium supplemented with 500 &#x003bc;g/mL hygromycin B. CHO cells stably expressing rM1, hM3, or hM5 were plated at a seeding density of 50,000 cells/100 &#x003bc;L/well. CHO cells stably coexpressing hM2/G<sub>qi5</sub> and ratM4/G<sub>qi5</sub> were plated at a seeding density of 60,000 cells/100 &#x003bc;L/well. For calcium mobilization, cells were incubated in antibiotic-free medium overnight at 37&#x000b0;C/5% CO<sub>2</sub> and assayed the next day.</p></div><div id="ml129.s11"><h3>Calcium Mobilization Assay</h3><p>Cells were loaded with calcium indicator dye [2 &#x003bc;M Fluo-4 acetoxymethyl ester (50 &#x003bc;L/well) prepared as a stock in DMSO and mixed in a 1:1 ratio with 10% Pluronic acid F-127 in assay buffer (1xHanks&#x02019; balanced salt solution supplemented with 20 mM HEPES and 2.5 mM probenecid, pH 7.4)] for 45 min at 37 &#x000b0;C. Dye was removed and replaced with the appropriate volume of assay buffer. All compounds were serially diluted in assay buffer for a final 2x stock in 0.6% DMSO. This stock was then added to the assay plate for a final DMSO concentration of 0.3%. Acetylcholine (EC<sub>20</sub> concentration or full dose-response curve) was prepared at a 10x stock solution in assay buffer before addition to assay plates. Calcium mobilization was measured at 25 &#x000b0;C using a FLEXstation II (Molecular Devices, Sunnyvale, CA). Cells were preincubated with test compound (or vehicle) for 1.5 min before the addition of the agonist, acetylcholine. Cells were then stimulated for 50 s with a submaximal concentration (EC<sub>20</sub>) or a full dose-response curve of acetylcholine. The signal amplitude was first normalized to baseline and then as a percentage of the maximal response to acetylcholine.</p></div><div id="ml129.s12"><h3>Summary of Screen</h3><p>This screen was performed in the pilot phase, the MLSCN, when the MLSMR compound collection at
Vanderbilt only contained 65K compounds. From the primary M1 screen of 65K compounds, ~12 putative
M1 PAMs were identified with an average Z&#x02019; score of 0.70&#x000b1;0.09. The confirmation
screen (singles at 10 &#x003bc;M) produced two lead compounds, one of which is still in chemical
lead optimization. The other, CID 3008304, represented a unique, and never before seen,
pharmacological profile (<a class="figpopup" href="/books/NBK50691/figure/ml129.f1/?report=objectonly" target="object" rid-figpopup="figml129f1" rid-ob="figobml129f1">Figure 1</a>) in that it was a PAM
of all the G<sub>q</sub>-coupled mAChRs (M1 EC<sub>50</sub> =6.1 &#x003bc;M, M3 EC<sub>50</sub> =6.4 &#x003bc;M and M5 EC<sub>50</sub> = 4.1 &#x003bc;M), but devoid of activity at the G<sub>i/o</sub>-coupled M2 and M4. (<a class="bk_pop" href="#ml129.r12">12</a>) This led us to predict it would be possible to dial-in or dial-out different mAChR subtypes and potentially develop an M1 selective PAM, an M3 selective PAM and/or an M5 selective PAM from this non-selective lead through chemical optimization. (<a class="bk_pop" href="#ml129.r13">13</a>)</p><div class="iconblock whole_rhythm clearfix ten_col fig" id="figml129f1" co-legend-rid="figlgndml129f1"><a href="/books/NBK50691/figure/ml129.f1/?report=objectonly" target="object" title="Figure 1" class="img_link icnblk_img figpopup" rid-figpopup="figml129f1" rid-ob="figobml129f1"><img class="small-thumb" src="/books/NBK50691/bin/ml129f1.gif" src-large="/books/NBK50691/bin/ml129f1.jpg" alt="Figure 1. CRCs at M1&#x02013;M5 for HTS lead CID 3008304. CID 3008304 is a pan Gq-M1, M3, M5 PAM." /></a><div class="icnblk_cntnt" id="figlgndml129f1"><h4 id="ml129.f1"><a href="/books/NBK50691/figure/ml129.f1/?report=objectonly" target="object" rid-ob="figobml129f1">Figure 1</a></h4><p class="float-caption no_bottom_margin">CRCs at M1&#x02013;M5 for HTS lead CID 3008304. CID 3008304 is a pan G<sub>q</sub>-M1, M3, M5 PAM. </p></div></div></div><div id="ml129.s13"><h3>Probe Chemical Lead Optimization Strategy</h3><p>For the lead optimization of CID 3008304, we employed a 2-dimensional library approach,
evaluating 8 diverse isatins (<b>1</b>&#x02013;<b>8</b>) in combination with 12
(<b>9</b>&#x02013;<b>20</b>) functionalized benzyl halides to afford 92/96 analogs of
CID 3008304 (<b>21</b>&#x02013;<b>112</b>) (<a class="figpopup" href="/books/NBK50691/figure/ml129.f4/?report=objectonly" target="object" rid-figpopup="figml129f4" rid-ob="figobml129f4">Scheme
1</a>). Yields were generally good providing the desired products in yields ranging from
20&#x02013;95%. (<a class="bk_pop" href="#ml129.r13">13</a>) In order to evaluate the
analogs expeditiously, we screened them in a single point format at a 30 &#x003bc;M final concentration in Ca<sup>2+</sup> mobilization assays using M5 and M1 cells receiving a fixed submaximal concentration (~EC<sub>10</sub>) of ACh (<a class="figpopup" href="/books/NBK50691/figure/ml129.f2/?report=objectonly" target="object" rid-figpopup="figml129f2" rid-ob="figobml129f2">Figure 2</a>). This method efficiently triaged analogs displaying high M1 vs. M5 or M5 vs. M1 preference. Interestingly, some analogs displayed robust potentiation effects at M5 (i.e. elevation of ACh ~EC<sub>10</sub> to &#x0003e;50&#x02013;60% of maximum ACh response) with absent or weak potentiation at M1, thus exhibiting strong preference for M5 versus M1 activity (subject of this report). (<a class="bk_pop" href="#ml129.r13">13</a>) Other analogs proved to be highly M1&#x02013;preferring (subject of future probe report). A similar exercise with M3 cells afforded no M3-preferring PAMs thus far.</p><div class="iconblock whole_rhythm clearfix ten_col fig" id="figml129f4" co-legend-rid="figlgndml129f4"><a href="/books/NBK50691/figure/ml129.f4/?report=objectonly" target="object" title="Scheme 1" class="img_link icnblk_img figpopup" rid-figpopup="figml129f4" rid-ob="figobml129f4"><img class="small-thumb" src="/books/NBK50691/bin/ml129f4.gif" src-large="/books/NBK50691/bin/ml129f4.jpg" alt="Scheme 1. Synthesis of an 8x12 member library of analogs of CID 3008304." /></a><div class="icnblk_cntnt" id="figlgndml129f4"><h4 id="ml129.f4"><a href="/books/NBK50691/figure/ml129.f4/?report=objectonly" target="object" rid-ob="figobml129f4">Scheme 1</a></h4><p class="float-caption no_bottom_margin">Synthesis of an 8x12 member library of analogs of CID 3008304. </p></div></div><div class="iconblock whole_rhythm clearfix ten_col fig" id="figml129f2" co-legend-rid="figlgndml129f2"><a href="/books/NBK50691/figure/ml129.f2/?report=objectonly" target="object" title="Figure 2" class="img_link icnblk_img figpopup" rid-figpopup="figml129f2" rid-ob="figobml129f2"><img class="small-thumb" src="/books/NBK50691/bin/ml129f2.gif" src-large="/books/NBK50691/bin/ml129f2.jpg" alt="Figure 2. Screen of analog library (compounds 21&#x02013;112) at 30 &#x003bc;M for potentiation of submaximal acetylcholine (~EC10) in M1 (A) and M5 (B) cells by Ca2+ assay (data shown are means +/&#x02212; SEM, N &#x02265; 3)." /></a><div class="icnblk_cntnt" id="figlgndml129f2"><h4 id="ml129.f2"><a href="/books/NBK50691/figure/ml129.f2/?report=objectonly" target="object" rid-ob="figobml129f2">Figure 2</a></h4><p class="float-caption no_bottom_margin">Screen of analog library (compounds <i>21</i>&#x02013;<i>112)</i> at 30 <i>&#x003bc;M</i> for potentiation of submaximal acetylcholine (~EC<sub>10</sub>) in M1 (A) and M5 (B) cells by Ca<sup>2</sup>+ assay (data shown are means +/&#x02212; SEM, N &#x02265; 3). </p></div></div><p>In terms of maximal potentiation efficacy, SAR from the initial 30 &#x003bc;M screen of the
entire library (<b>21</b>&#x02013;<b>112</b>) suggested that 5-OCF<sub>3</sub>
substitution of the isatin core (R<sub>1</sub>) was generally favored for increased M5 versus M1
activity, while halogen substitutions at the 4- position conferred a more dual M1/M5 activity (<a class="figpopup" href="/books/NBK50691/figure/ml129.f2/?report=objectonly" target="object" rid-figpopup="figml129f2" rid-ob="figobml129f2">Figure 2</a>). Indeed, most of the 5-OCF<sub>3</sub> substituted compounds chosen from the initial screen possessed 1&#x02013;5 &#x003bc;M potencies at M5 and &#x0003e;30 &#x003bc;M potencies at M1 (<a class="figpopup" href="/books/NBK50691/table/ml129.t1/?report=objectonly" target="object" rid-figpopup="figml129t1" rid-ob="figobml129t1">Table 1</a>). Numerous benzylic substitutions (R<sub>2</sub>) were tolerated for M1 and M5 activity, depending on the isatin core (R<sub>1</sub>). Methoxybenzyls were generally favored for M5 versus M1 activity whereas trifluoromethylbenzyls were generally favored for dual M1/M5 potentiation activity (<a class="figpopup" href="/books/NBK50691/table/ml129.t1/?report=objectonly" target="object" rid-figpopup="figml129t1" rid-ob="figobml129t1">Table 1</a>). Most other simple congeners, including those with various methyl substitutions at R<sub>1</sub> or R<sub>2</sub> displayed weak or negligible potentiation at either receptor. In light of the high M5 versus M1 potentiation preference displayed by CID 42633508 (1.16 &#x003bc;M M5 EC<sub>50</sub> and &#x0003e;30 &#x003bc;M M1 EC<sub>50</sub>) in these assays, the compound was further profiled across the rtemaing subtypes. As shown in <a class="figpopup" href="/books/NBK50691/figure/ml129.f3/?report=objectonly" target="object" rid-figpopup="figml129f3" rid-ob="figobml129f3">Figure 3A</a>, the full subtype-selectivity profile of this compound was obtained in similar Ca<sup>2+</sup> assays using M2, M3, and M4 cells. CID 42633508 had no effect on M2 and M4, and afforded only modest activation of M1 and M3 at 30 &#x003bc;M (~30%); thus, CID 42633508 provides &#x0003e;30x selectivity for M5 versus the other four subtypes, thus representing the first highly M5-preferring muscarinic ligand ever reported. (<a class="bk_pop" href="#ml129.r13">13</a>)</p><div class="iconblock whole_rhythm clearfix ten_col table-wrap" id="figml129t1"><a href="/books/NBK50691/table/ml129.t1/?report=objectonly" target="object" title="Table 1" class="img_link icnblk_img figpopup" rid-figpopup="figml129t1" rid-ob="figobml129t1"><img class="small-thumb" src="/books/NBK50691/table/ml129.t1/?report=thumb" src-large="/books/NBK50691/table/ml129.t1/?report=previmg" alt="Table 1. Structures and activities at M1 and M5 of CID 42633508." /></a><div class="icnblk_cntnt"><h4 id="ml129.t1"><a href="/books/NBK50691/table/ml129.t1/?report=objectonly" target="object" rid-ob="figobml129t1">Table 1</a></h4><p class="float-caption no_bottom_margin">Structures and activities at M1 and M5 of CID 42633508. </p></div></div><div class="iconblock whole_rhythm clearfix ten_col fig" id="figml129f3" co-legend-rid="figlgndml129f3"><a href="/books/NBK50691/figure/ml129.f3/?report=objectonly" target="object" title="Figure 3" class="img_link icnblk_img figpopup" rid-figpopup="figml129f3" rid-ob="figobml129f3"><img class="small-thumb" src="/books/NBK50691/bin/ml129f3.gif" src-large="/books/NBK50691/bin/ml129f3.jpg" alt="Figure 3. In vitro Moelcular Pharmacology of CID 42633508." /></a><div class="icnblk_cntnt" id="figlgndml129f3"><h4 id="ml129.f3"><a href="/books/NBK50691/figure/ml129.f3/?report=objectonly" target="object" rid-ob="figobml129f3">Figure 3</a></h4><p class="float-caption no_bottom_margin">In vitro Moelcular Pharmacology of CID 42633508. A) mAChRseelectivity; B) Effect of compound alone versus in presence of EC<sub>20</sub> of ACh: C) Fold-shift experiment (14-fold shift of ACh CRC); D) [<sup>3</sup>H]-NMS binding experiment- CID 42633508 does not bind at orthosteric <a href="/books/NBK50691/figure/ml129.f3/?report=objectonly" target="object" rid-ob="figobml129f3">(more...)</a></p></div></div><p>Subsequent experiments (<a class="figpopup" href="/books/NBK50691/figure/ml129.f3/?report=objectonly" target="object" rid-figpopup="figml129f3" rid-ob="figobml129f3">Figure 3</a>) were performed to
determine if CID 42633508 was a true PAM. As shown in <a class="figpopup" href="/books/NBK50691/figure/ml129.f3/?report=objectonly" target="object" rid-figpopup="figml129f3" rid-ob="figobml129f3">Figure
3B</a>, CID 42633508 had no effect on M5 cells alone, but caused a dose-dependent increase in M5
receptor activation in the presence of a submaximal (EC<sub>20</sub>) concentration of ACh. At a fixed 30 &#x003bc;M concentration, CID 42633508 elicited a 14-fold leftward shift of the ACh concentration-response-curve (CRC) (<a class="figpopup" href="/books/NBK50691/figure/ml129.f3/?report=objectonly" target="object" rid-figpopup="figml129f3" rid-ob="figobml129f3">Figure 3C</a>). In [<sup>3</sup>H]-NMS binding experiments, CID 42633508 did not displace the orthosteric radio-ligand whereas atropine, an orthosteric antagonist, afforded complete displacement (<a class="figpopup" href="/books/NBK50691/figure/ml129.f3/?report=objectonly" target="object" rid-figpopup="figml129f3" rid-ob="figobml129f3">Figure 3D</a>). In order to address the mechanism of M5 PAM activity, we measured the effect of fixed 30 &#x003bc;M CID 42633508 on ACh competition with [<sup>3</sup>H]-NMS binding, and found a 10-fold increase in ACh affinity for M5 &#x02013; a value close to the leftward fold-shift (14-fold). Thus, the mechanism of M5 potentiation by CID 42633508 is due in part to the enhancement of ACh binding. Given these data, CID 42633508 is a true PAM of M5, devoid of intrinsic agonist activity. (<a class="bk_pop" href="#ml129.r13">13</a>)</p><p>We then evaluated pharmacokinetics and brain penetration for the M5 PAM to evaluate its ability
to serve as an <i>in vivo</i> probe. Unfortunately, CID 42633508 is characterized by poor
systemic absorption after intraperitoneal administration with maximum concentration in plasma (161.7
ng/mL) being achieved within 1 hour. However, it is slowly eliminated from systemic circulation and
has elimination half life of 4.5 hours. Although quickly taken up in the brain, it exhibits poor
brain penetration with AUC<sub>brain</sub>/AUC<sub>plasma</sub> value of 0.25. (<a class="bk_pop" href="#ml129.r13">13</a>) Future lead optimization will focus on improving brain penetration. At this point, the Lead Profiling Screen (68 GPCRs, ion channels and transporters) from MDS Pharma was performed on CID 42633508 to determine a broader ancillary pharmacology profile for this MLPCN probe. In addition to selectivity versus the mGluR family, CID 42633508 possessed reasonably clean ancillary pharmacology in a 68 Target MDS GPCR, Ion Channel and Transporter Lead Profiling Panel, displaying no significant activity (no inhibition &#x0003e;50% at 10 &#x003bc;M) for 59 of the 68 targets. CID 42633508 did have activity at 9 targets: A3A (65%@10 &#x003bc;M), A2A (99%@10 &#x003bc;M), NET (66%@10 &#x003bc;M), CB1 (84%@10 &#x003bc;M), D4 (61%@10 &#x003bc;M), H1 (62%@10 &#x003bc;M), H2 (55%@10 &#x003bc;M), MOP (70%@10 &#x003bc;M) and hERG (60%@10 &#x003bc;M). Of these, only two possessed <i>K</i><i><sub>i</sub></i>s below 10 &#x003bc;M: A2A (760 nM) and CB1 (2.2 &#x003bc;M). (<a class="bk_pop" href="#ml129.r14">14</a>)</p><p>Thus, CID 42633508 is a first-in&#x02013;class M5 PAM, the first M5-selective ligand (&#x0003e;30-fold
versus M1&#x02013;M4) with generally clean ancillary pharmacology. CNS penetration is poor however,
restricting CID 42633508 for use as an in vitro probe. (<a class="bk_pop" href="#ml129.r13">13</a>) Future work will focus on developing a centrally penetrant M5 PAM devoid of any ancillary pharmacology for use as an in vivo probe.</p></div><div id="ml129.s14"><h3>Synthetic procedure (large scale) and spectral data for CID 42633508</h3><div id="ml129.fu2" class="figure"><div class="graphic"><img src="/books/NBK50691/bin/ml129fu3.jpg" alt="Image ml129fu3" /></div></div><div id="ml129.s15"><h4>CID 42633508, 1-(4-methoxybenzyl)-5-(trifluoromethoxy)indoline-2,3-dione [<a href="/pcsubstance/?term=ML129[synonym]" ref="pagearea=body&amp;targetsite=entrez&amp;targetcat=term&amp;targettype=pubchem">ML129</a>]</h4><p>To a vial containing ACN (15 mL) was added 5-trifluoromethyoxyisatin (1.00 g, 4.33 mmol),
K<sub>2</sub>CO<sub>3</sub> (8.66 mmol, 2.0 eq), KI (0.43 mmol, 0.1 eq), and 4-methoxybenzyl
chloride (4.76 mmol, 1.1 eq). The reaction was stirred for ~24 hours at room temperature while monitoring by TLC. After judging complete, the reaction was partitioned between EtOAc and H<sub>2</sub>O, and the combined organics were dried over MgSO<sub>4</sub>, filtered, and then concentrated <i>in vacuo</i> to afford the pure 1-(4-methoxybenzyl)-5-(trifluoromethoxy)indoline-2,3-dione title compound as an orange solid (1.50 g, 4.26 mmol, 98%). <sup>1</sup>H-NMR (400MHz, <i>d</i><i><sub>6</sub></i> - DMSO) <i>&#x003b4;</i> 7.60 (m, 2H), 7.36 (d, <i>J</i> = 8.7, 2H), 7.04 (m, 1H), 6.89 (m, 2H), 4.84 (s, 2H), 3.71 (s, 3H). <sup>13</sup>C-NMR (100MHz, <i>d</i><i><sub>6</sub></i> - DMSO) <i>&#x003b4;</i> 181.99, 158.73, 158.33, 149.00, 143.83, 130.35, 128.88, 126.94, 121.32, 118.79, 117.66, 114.02, 112.36, 55.05, 42.45. LCMS (214 nm) 3.37 min (&#x0003e;98%); <i>m/z</i> 352.1 [M+H]. HRMS calcd for C<sub>17</sub>H<sub>13</sub>F<sub>3</sub>NO<sub>4</sub> [M+H] 352.0797 found 352.0795.</p></div></div><div id="ml129.s16"><h3>MLS#s</h3><p>002608917, 002608918, 002608916, 002608915 (Probe, 500 mg)</p></div></div><div id="ml129.rl1"><h2 id="_ml129_rl1_">Bibliography</h2><dl class="temp-labeled-list"><dt>1.</dt><dd><div class="bk_ref" id="ml129.r1">Bonner TI, Buckley NJ, Young AC, Brann MR. <span><span class="ref-journal">Science. </span>1987;<span class="ref-vol">237</span>:527532.</span> [<a href="https://pubmed.ncbi.nlm.nih.gov/3037705" ref="pagearea=cite-ref&amp;targetsite=entrez&amp;targetcat=link&amp;targettype=pubmed">PubMed<span class="bk_prnt">: 3037705</span></a>]</div></dd><dt>2.</dt><dd><div class="bk_ref" id="ml129.r2">Bonner TI, Young AC, Brann MR, Buckley NJ. <span><span class="ref-journal">Neuron. </span>1988;<span class="ref-vol">1</span>:403410.</span> [<a href="https://pubmed.ncbi.nlm.nih.gov/3272174" ref="pagearea=cite-ref&amp;targetsite=entrez&amp;targetcat=link&amp;targettype=pubmed">PubMed<span class="bk_prnt">: 3272174</span></a>]</div></dd><dt>3.</dt><dd><div class="bk_ref" id="ml129.r3">Wess J. <span><span class="ref-journal">Annu. Rev. Pharmacol. Toxicol. </span>2004;<span class="ref-vol">44</span>:423450.</span> [<a href="https://pubmed.ncbi.nlm.nih.gov/14744253" ref="pagearea=cite-ref&amp;targetsite=entrez&amp;targetcat=link&amp;targettype=pubmed">PubMed<span class="bk_prnt">: 14744253</span></a>]</div></dd><dt>4.</dt><dd><div class="bk_ref" id="ml129.r4">Langmead CJ, Watson J, Reavill C. <span><span class="ref-journal">Pharmacol. Ther. </span>2008;<span class="ref-vol">117</span>:232243.</span> [<a href="https://pubmed.ncbi.nlm.nih.gov/18082893" ref="pagearea=cite-ref&amp;targetsite=entrez&amp;targetcat=link&amp;targettype=pubmed">PubMed<span class="bk_prnt">: 18082893</span></a>]</div></dd><dt>5.</dt><dd><div class="bk_ref" id="ml129.r5">Birdsall NJM, Lazareno S. <span><span class="ref-journal">Mini. Rev. Med. Chem. </span>2005;<span class="ref-vol">5</span>:523543.</span> [<a href="https://pubmed.ncbi.nlm.nih.gov/15974931" ref="pagearea=cite-ref&amp;targetsite=entrez&amp;targetcat=link&amp;targettype=pubmed">PubMed<span class="bk_prnt">: 15974931</span></a>]</div></dd><dt>6.</dt><dd><div class="bk_ref" id="ml129.r6">Conn PJ, Christopoulos A, Lindsley CW. <span><span class="ref-journal">Nat. Rev. Durg Disc. </span>2009;<span class="ref-vol">8</span>:4154.</span> [<a href="/pmc/articles/PMC2907734/" ref="pagearea=cite-ref&amp;targetsite=entrez&amp;targetcat=link&amp;targettype=pmc">PMC free article<span class="bk_prnt">: PMC2907734</span></a>] [<a href="https://pubmed.ncbi.nlm.nih.gov/19116626" ref="pagearea=cite-ref&amp;targetsite=entrez&amp;targetcat=link&amp;targettype=pubmed">PubMed<span class="bk_prnt">: 19116626</span></a>]</div></dd><dt>7.</dt><dd><div class="bk_ref" id="ml129.r7">Yamada M, Lamping KG, Duttaroy A, Zhang W, Cui Y, Bymaster FP, McKinzie DL, Felder CC, Deng C, Faraci FM, Wess J. <span><span class="ref-journal">Proc. Natl. Acad. Sci. </span>2001;<span class="ref-vol">98</span>:1409614101.</span> [<a href="/pmc/articles/PMC61174/" ref="pagearea=cite-ref&amp;targetsite=entrez&amp;targetcat=link&amp;targettype=pmc">PMC free article<span class="bk_prnt">: PMC61174</span></a>] [<a href="https://pubmed.ncbi.nlm.nih.gov/11707605" ref="pagearea=cite-ref&amp;targetsite=entrez&amp;targetcat=link&amp;targettype=pubmed">PubMed<span class="bk_prnt">: 11707605</span></a>]</div></dd><dt>8.</dt><dd><div class="bk_ref" id="ml129.r8">Araya R, Noguchi T, Yuhki M, Kitamura N, Higuchi M, Saido TC, Seki K, Itohara S, Kawano M, Tanemura K, Takashima A, Yamada K, Kondoh Y, Kanno I, Wess J, Yamada M. <span><span class="ref-journal">Neurobiol. Dis. </span>2006;<span class="ref-vol">24</span>:334344.</span> [<a href="https://pubmed.ncbi.nlm.nih.gov/16956767" ref="pagearea=cite-ref&amp;targetsite=entrez&amp;targetcat=link&amp;targettype=pubmed">PubMed<span class="bk_prnt">: 16956767</span></a>]</div></dd><dt>9.</dt><dd><div class="bk_ref" id="ml129.r9">Wess J, Eglen RM, Gautam D. <span><span class="ref-journal">Nat. Rev. Drug Discov. </span>2007;<span class="ref-vol">6</span>:721733.</span> [<a href="https://pubmed.ncbi.nlm.nih.gov/17762886" ref="pagearea=cite-ref&amp;targetsite=entrez&amp;targetcat=link&amp;targettype=pubmed">PubMed<span class="bk_prnt">: 17762886</span></a>]</div></dd><dt>10.</dt><dd><div class="bk_ref" id="ml129.r10">Basile AS, Fedorova I, Zapata A, Liu X, Shippenberg T, Duttaroy A, Yamada M, Wess J. <span><span class="ref-journal">Proc. Natl. Acad. Sci. </span>2002;<span class="ref-vol">99</span>:1145211457.</span> [<a href="/pmc/articles/PMC123277/" ref="pagearea=cite-ref&amp;targetsite=entrez&amp;targetcat=link&amp;targettype=pmc">PMC free article<span class="bk_prnt">: PMC123277</span></a>] [<a href="https://pubmed.ncbi.nlm.nih.gov/12154229" ref="pagearea=cite-ref&amp;targetsite=entrez&amp;targetcat=link&amp;targettype=pubmed">PubMed<span class="bk_prnt">: 12154229</span></a>]</div></dd><dt>11.</dt><dd><div class="bk_ref" id="ml129.r11">Thomsen M, Woldbye DPD, Wortwein G, Fink-Jensen A, Wess J, Caine SB. <span><span class="ref-journal">J. Neurosci. </span>2005;<span class="ref-vol">25</span>:81418149.</span> [<a href="/pmc/articles/PMC6725551/" ref="pagearea=cite-ref&amp;targetsite=entrez&amp;targetcat=link&amp;targettype=pmc">PMC free article<span class="bk_prnt">: PMC6725551</span></a>] [<a href="https://pubmed.ncbi.nlm.nih.gov/16148222" ref="pagearea=cite-ref&amp;targetsite=entrez&amp;targetcat=link&amp;targettype=pubmed">PubMed<span class="bk_prnt">: 16148222</span></a>]</div></dd><dt>12.</dt><dd><div class="bk_ref" id="ml129.r12">Marlo JE, Niswender CM, Days EL, Bridges TM, Xiang Y, Rodriguez AL, Shirey JK, Brady AE, Nalywajko T, Luo Q, Austin CA, Williams MB, Kim K, Williams R, Orton D, Brown HA, Lindsley CW, Weaver CD, Conn PJ. <span><span class="ref-journal">Mol. Pharmacol. </span>2009;<span class="ref-vol">75</span>:577588.</span> [<a href="/pmc/articles/PMC2684909/" ref="pagearea=cite-ref&amp;targetsite=entrez&amp;targetcat=link&amp;targettype=pmc">PMC free article<span class="bk_prnt">: PMC2684909</span></a>] [<a href="https://pubmed.ncbi.nlm.nih.gov/19047481" ref="pagearea=cite-ref&amp;targetsite=entrez&amp;targetcat=link&amp;targettype=pubmed">PubMed<span class="bk_prnt">: 19047481</span></a>]</div></dd><dt>13.</dt><dd><div class="bk_ref" id="ml129.r13">Bridges TM, Marlo JE, Niswender CM, Jones JK, Jadhav SB, Gentry PR, Weaver CD, Conn PJ, Lindsley CW. <span><span class="ref-journal">J. Med. Chem. </span>2009;<span class="ref-vol">52</span>:34453448.</span> [<a href="/pmc/articles/PMC3875304/" ref="pagearea=cite-ref&amp;targetsite=entrez&amp;targetcat=link&amp;targettype=pmc">PMC free article<span class="bk_prnt">: PMC3875304</span></a>] [<a href="https://pubmed.ncbi.nlm.nih.gov/19438238" ref="pagearea=cite-ref&amp;targetsite=entrez&amp;targetcat=link&amp;targettype=pubmed">PubMed<span class="bk_prnt">: 19438238</span></a>]</div></dd><dt>14.</dt><dd><div class="bk_ref" id="ml129.r14">For information on the MDS Pharma Lead Profiling Screen see: <a href="http://www.mdsps.com" ref="pagearea=cite-ref&amp;targetsite=external&amp;targetcat=link&amp;targettype=uri">www<wbr style="display:inline-block"></wbr>.mdsps.com</a></div></dd></dl></div><div id="ml129.app1"><h2 id="_ml129_app1_">APPENDIX I. Solubility, Stability and Reactivity data as determined by Absorption Systems</h2><div id="ml129.s17"><h3>Solubility</h3><p>Solubility in PBS (at pH = 7.4) for <a href="/pcsubstance/?term=ML129[synonym]" ref="pagearea=body&amp;targetsite=entrez&amp;targetcat=term&amp;targettype=pubchem">ML129</a> was 3.14 &#x003bc;M.</p></div><div id="ml129.s18"><h3>Stability</h3><p>Stability (at room temperature = 23 &#x000b0;C) for <a href="/pcsubstance/?term=ML129[synonym]" ref="pagearea=body&amp;targetsite=entrez&amp;targetcat=term&amp;targettype=pubchem">ML129</a> in PBS (no antioxidants or other protectorants and DMSO concentration below 0.1%) is shown in the table below. After 48 hours, the percent of parent compound remaining was 79%, but the assay variability over the course of the experiment ranged from a low of 79% (at 1 hour and 48 hours) to a high of 112% (at 30 minutes).</p><div id="ml129.tu2" class="table"><p class="large-table-link" style="display:none"><span class="right"><a href="/books/NBK50691/table/ml129.tu2/?report=objectonly" target="object">View in own window</a></span></p><div class="large_tbl" id="__ml129.tu2_lrgtbl__"><table><thead><tr><th id="hd_h_ml129.tu2_1_1_1_1" rowspan="1" colspan="1" style="text-align:center;vertical-align:bottom;"></th><th id="hd_h_ml129.tu2_1_1_1_2" colspan="7" rowspan="1" style="text-align:center;vertical-align:bottom;">Percent Remaining (%)</th></tr><tr><th headers="hd_h_ml129.tu2_1_1_1_1" id="hd_h_ml129.tu2_1_1_2_1" rowspan="1" colspan="1" style="text-align:center;vertical-align:bottom;">Compound</th><th headers="hd_h_ml129.tu2_1_1_1_2" id="hd_h_ml129.tu2_1_1_2_2" rowspan="1" colspan="1" style="text-align:center;vertical-align:bottom;">0 Min</th><th headers="hd_h_ml129.tu2_1_1_1_2" id="hd_h_ml129.tu2_1_1_2_3" rowspan="1" colspan="1" style="text-align:center;vertical-align:bottom;">15 Min</th><th headers="hd_h_ml129.tu2_1_1_1_2" id="hd_h_ml129.tu2_1_1_2_4" rowspan="1" colspan="1" style="text-align:center;vertical-align:bottom;">30 Min</th><th headers="hd_h_ml129.tu2_1_1_1_2" id="hd_h_ml129.tu2_1_1_2_5" rowspan="1" colspan="1" style="text-align:center;vertical-align:bottom;">1 Hour</th><th headers="hd_h_ml129.tu2_1_1_1_2" id="hd_h_ml129.tu2_1_1_2_6" rowspan="1" colspan="1" style="text-align:center;vertical-align:bottom;">2 Hour</th><th headers="hd_h_ml129.tu2_1_1_1_2" id="hd_h_ml129.tu2_1_1_2_7" rowspan="1" colspan="1" style="text-align:center;vertical-align:bottom;">24 Hour</th><th headers="hd_h_ml129.tu2_1_1_1_2" id="hd_h_ml129.tu2_1_1_2_8" rowspan="1" colspan="1" style="text-align:center;vertical-align:bottom;">48 Hour</th></tr></thead><tbody><tr><td headers="hd_h_ml129.tu2_1_1_1_1 hd_h_ml129.tu2_1_1_2_1" rowspan="1" colspan="1" style="text-align:center;vertical-align:top;"><a href="/pcsubstance/?term=ML129[synonym]" ref="pagearea=body&amp;targetsite=entrez&amp;targetcat=term&amp;targettype=pubchem">ML129</a></td><td headers="hd_h_ml129.tu2_1_1_1_2 hd_h_ml129.tu2_1_1_2_2" rowspan="1" colspan="1" style="text-align:center;vertical-align:top;">100</td><td headers="hd_h_ml129.tu2_1_1_1_2 hd_h_ml129.tu2_1_1_2_3" rowspan="1" colspan="1" style="text-align:center;vertical-align:top;">112</td><td headers="hd_h_ml129.tu2_1_1_1_2 hd_h_ml129.tu2_1_1_2_4" rowspan="1" colspan="1" style="text-align:center;vertical-align:top;">112</td><td headers="hd_h_ml129.tu2_1_1_1_2 hd_h_ml129.tu2_1_1_2_5" rowspan="1" colspan="1" style="text-align:center;vertical-align:top;">79</td><td headers="hd_h_ml129.tu2_1_1_1_2 hd_h_ml129.tu2_1_1_2_6" rowspan="1" colspan="1" style="text-align:center;vertical-align:top;">108</td><td headers="hd_h_ml129.tu2_1_1_1_2 hd_h_ml129.tu2_1_1_2_7" rowspan="1" colspan="1" style="text-align:center;vertical-align:top;">104</td><td headers="hd_h_ml129.tu2_1_1_1_2 hd_h_ml129.tu2_1_1_2_8" rowspan="1" colspan="1" style="text-align:center;vertical-align:top;">79</td></tr></tbody></table></div></div></div><div id="ml129.s19"><h3>Reactivity</h3><p>As assessed through a glutathione (GSH) trapping experiment in phosphate buffered saline (with a substrate concentration of typically 5&#x02013;50 &#x003bc;M and a GSH concentration of 2 &#x003bc;M, at t = 60 minutes), <a href="/pcsubstance/?term=ML129[synonym]" ref="pagearea=body&amp;targetsite=entrez&amp;targetcat=term&amp;targettype=pubchem">ML129</a> was found to form one detectable GSH adduct with an exact mass of 573.1652 (M+H). Relative to parent AUC (at t = 0), this conjugate was 13-fold more abundant at 60 minutes, but not knowing the respective extinction coefficients (for parent molecule and GSH conjugate) it is difficult to quantify the extent of GSH reactivity. Furthermore, given that the reported solubility for <a href="/pcsubstance/?term=ML129[synonym]" ref="pagearea=body&amp;targetsite=entrez&amp;targetcat=term&amp;targettype=pubchem">ML129</a> (in PBS at pH = 7.4 &#x02013; determined at Absorption Systems<sup><a class="bk_pop" href="#ml129.fn1">*</a></sup>) is only 3.14 &#x003bc;M, this apparent large increase in the concentration of the GSH adduct might be a result of dramatically increased solubility for the GSH adduct over the relatively insoluble substrate, which would then inflate the relative abundance of the GSH conjugate. And, while it is possible to propose a structure for this mass which corresponds to displacement of the trifluoromethoxy group on the isatin by GSH, it is interesting to note that this sort of reactivity was not observed for the same isatin core in <a href="/pcsubstance/?term=ML172[synonym]" ref="pagearea=body&amp;targetsite=entrez&amp;targetcat=term&amp;targettype=pubchem">ML172</a>.</p></div></div><div id="ml129.app2"><h2 id="_ml129_app2_">APPENDIX II. Liquid Chromatography-Mass Spectrometry (LCMS) and Nuclear Magnetic Resonance (NMR) as prepared by Vanderbilt Specialized Chemistry Center</h2><div id="ml129.fu3" class="figure"><div class="graphic"><img src="/books/NBK50691/bin/ml129fu4.jpg" alt="Image ml129fu4" /></div></div><div id="ml129.fu4" class="figure"><div class="graphic"><img src="/books/NBK50691/bin/ml129fu5.jpg" alt="Image ml129fu5" /></div></div><div id="ml129.fu5" class="figure"><div class="graphic"><img src="/books/NBK50691/bin/ml129fu6.jpg" alt="Image ml129fu6" /></div></div></div><h2 id="NBK50691_footnotes">Footnotes</h2><dl class="temp-labeled-list small"><dt>*</dt><dd><div id="ml129.fn1"><p class="no_top_margin">Solubility (PBS at pH = 7.4), Stability and Reactivity experiments were conducted at Absorption Systems. For additional information see: <a href="https://www.absorption.com/site" ref="pagearea=body&amp;targetsite=external&amp;targetcat=link&amp;targettype=uri">https://www<wbr style="display:inline-block"></wbr>.absorption.com/site</a></p></div></dd></dl><div id="bk_toc_contnr"></div></div></div>
<div class="post-content"><div><div class="half_rhythm"><a href="/books/about/copyright/">Copyright Notice</a></div><div class="small"><span class="label">Bookshelf ID: NBK50691</span><span class="label">PMID: <a href="https://pubmed.ncbi.nlm.nih.gov/21433383" title="PubMed record of this page" ref="pagearea=meta&amp;targetsite=entrez&amp;targetcat=link&amp;targettype=pubmed">21433383</a></span></div><div style="margin-top:2em" class="bk_noprnt"><a class="bk_cntns" href="/books/n/mlprobe/">Contents</a><div class="pagination bk_noprnt"><a class="active page_link prev" href="/books/n/mlprobe/ml130/" title="Previous page in this title">&lt; Prev</a><a class="active page_link next" href="/books/n/mlprobe/ml128/" title="Next page in this title">Next &gt;</a></div></div></div></div>
</div>
<!-- Custom content below content -->
<div class="col4">
</div>
<!-- Book content -->
<!-- Custom contetnt below bottom nav -->
<div class="col5">
</div>
</div>
<div id="rightcolumn" class="four_col col last">
<!-- Custom content above discovery portlets -->
<div class="col6">
<div id="ncbi_share_book"><a href="#" class="ncbi_share" data-ncbi_share_config="popup:false,shorten:true" ref="id=NBK50691&amp;db=books">Share</a></div>
</div>
<div xmlns:np="http://ncbi.gov/portal/XSLT/namespace" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"></div><div class="portlet"><div class="portlet_head"><div class="portlet_title"><h3><span>Views</span></h3></div><a name="Shutter" sid="1" href="#" class="portlet_shutter" title="Show/hide content" remembercollapsed="true" pgsec_name="PDF_download" id="Shutter"></a></div><div class="portlet_content"><ul xmlns:np="http://ncbi.gov/portal/XSLT/namespace" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" class="simple-list"><li><a href="/books/NBK50691/?report=reader">PubReader</a></li><li><a href="/books/NBK50691/?report=printable">Print View</a></li><li><a data-jig="ncbidialog" href="#_ncbi_dlg_citbx_NBK50691" data-jigconfig="width:400,modal:true">Cite this Page</a><div id="_ncbi_dlg_citbx_NBK50691" style="display:none" title="Cite this Page"><div class="bk_tt">Bridges TM, Lewis LM, Weaver CD, et al. Discovery of the first mAChR 5 (M5) selective ligand, an M5 Positive Allosteric Modulator (PAM) 2009 Dec 18 [Updated 2010 Oct 20]. In: Probe Reports from the NIH Molecular Libraries Program [Internet]. Bethesda (MD): National Center for Biotechnology Information (US); 2010-. <span class="bk_cite_avail"></span></div></div></li><li><a href="/books/NBK50691/pdf/Bookshelf_NBK50691.pdf">PDF version of this page</a> (1.3M)</li></ul></div></div><div class="portlet"><div class="portlet_head"><div class="portlet_title"><h3><span>In this Page</span></h3></div><a name="Shutter" sid="1" href="#" class="portlet_shutter" title="Show/hide content" remembercollapsed="true" pgsec_name="page-toc" id="Shutter"></a></div><div class="portlet_content"><ul xmlns:np="http://ncbi.gov/portal/XSLT/namespace" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" class="simple-list"><li><a href="#ml129.s2" ref="log$=inpage&amp;link_id=inpage">Probe Structure &amp; Characteristics</a></li><li><a href="#ml129.s3" ref="log$=inpage&amp;link_id=inpage">Recommendations for the scientific use of this probe</a></li><li><a href="#ml129.s7" ref="log$=inpage&amp;link_id=inpage">Screening Center Information: Assay Implementation and Screening</a></li><li><a href="#ml129.rl1" ref="log$=inpage&amp;link_id=inpage">Bibliography</a></li><li><a href="#ml129.app1" ref="log$=inpage&amp;link_id=inpage">Solubility, Stability and Reactivity data as determined by Absorption Systems</a></li><li><a href="#ml129.app2" ref="log$=inpage&amp;link_id=inpage">Liquid Chromatography-Mass Spectrometry (LCMS) and Nuclear Magnetic Resonance (NMR) as prepared by Vanderbilt Specialized Chemistry Center</a></li></ul></div></div><div class="portlet"><div class="portlet_head"><div class="portlet_title"><h3><span>Related information</span></h3></div><a name="Shutter" sid="1" href="#" class="portlet_shutter" title="Show/hide content" remembercollapsed="true" pgsec_name="discovery_db_links" id="Shutter"></a></div><div class="portlet_content"><ul><li class="brieflinkpopper"><a class="brieflinkpopperctrl" href="/books/?Db=pmc&amp;DbFrom=books&amp;Cmd=Link&amp;LinkName=books_pmc_refs&amp;IdsFromResult=2376710" ref="log$=recordlinks">PMC</a><div class="brieflinkpop offscreen_noflow">PubMed Central citations</div></li><li class="brieflinkpopper"><a class="brieflinkpopperctrl" href="/books/?Db=pcassay&amp;DbFrom=books&amp;Cmd=Link&amp;LinkName=books_pcassay_probe&amp;IdsFromResult=2376710" ref="log$=recordlinks">PubChem BioAssay for Chemical Probe</a><div class="brieflinkpop offscreen_noflow">PubChem BioAssay records reporting screening data for the development of the chemical probe(s) described in this book chapter</div></li><li class="brieflinkpopper"><a class="brieflinkpopperctrl" href="/books/?Db=pcsubstance&amp;DbFrom=books&amp;Cmd=Link&amp;LinkName=books_pcsubstance&amp;IdsFromResult=2376710" ref="log$=recordlinks">PubChem Substance</a><div class="brieflinkpop offscreen_noflow">Related PubChem Substances</div></li><li class="brieflinkpopper"><a class="brieflinkpopperctrl" href="/books/?Db=pubmed&amp;DbFrom=books&amp;Cmd=Link&amp;LinkName=books_pubmed_refs&amp;IdsFromResult=2376710" ref="log$=recordlinks">PubMed</a><div class="brieflinkpop offscreen_noflow">Links to PubMed</div></li></ul></div></div><div class="portlet"><div class="portlet_head"><div class="portlet_title"><h3><span>Similar articles in PubMed</span></h3></div><a name="Shutter" sid="1" href="#" class="portlet_shutter" title="Show/hide content" remembercollapsed="true" pgsec_name="PBooksDiscovery_RA" id="Shutter"></a></div><div class="portlet_content"><ul><li class="brieflinkpopper two_line"><a class="brieflinkpopperctrl" href="/pubmed/21433380" ref="ordinalpos=1&amp;linkpos=1&amp;log$=relatedreviews&amp;logdbfrom=pubmed"><span xmlns:np="http://ncbi.gov/portal/XSLT/namespace" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" class="invert">Review</span> Discovery of a Highly Selective in vitro and in vivo M4 Positive Allosteric Modulator (PAM).</a><span class="source">[Probe Reports from the NIH Mol...]</span><div class="brieflinkpop offscreen_noflow"><span xmlns:np="http://ncbi.gov/portal/XSLT/namespace" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" class="invert">Review</span> Discovery of a Highly Selective in vitro and in vivo M4 Positive Allosteric Modulator (PAM).<div class="brieflinkpopdesc"><em xmlns:np="http://ncbi.gov/portal/XSLT/namespace" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" class="author">Lewis LM, Bridges TM, Niswender CM, Weaver CD, Lindsley CW. </em><em xmlns:np="http://ncbi.gov/portal/XSLT/namespace" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" class="cit">Probe Reports from the NIH Molecular Libraries Program. 2010</em></div></div></li><li class="brieflinkpopper two_line"><a class="brieflinkpopperctrl" href="/pubmed/23762960" ref="ordinalpos=1&amp;linkpos=2&amp;log$=relatedreviews&amp;logdbfrom=pubmed"><span xmlns:np="http://ncbi.gov/portal/XSLT/namespace" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" class="invert">Review</span> Development of the First Highly Selective mAChR 5 (M(5)) Positive Allosteric Modulator (PAM).</a><span class="source">[Probe Reports from the NIH Mol...]</span><div class="brieflinkpop offscreen_noflow"><span xmlns:np="http://ncbi.gov/portal/XSLT/namespace" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" class="invert">Review</span> Development of the First Highly Selective mAChR 5 (M(5)) Positive Allosteric Modulator (PAM).<div class="brieflinkpopdesc"><em xmlns:np="http://ncbi.gov/portal/XSLT/namespace" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" class="author">Bridges TM, Lewis LM, Weaver CD, Wood MR, Daniels JS, Conn PJ, Lindsley CW. </em><em xmlns:np="http://ncbi.gov/portal/XSLT/namespace" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" class="cit">Probe Reports from the NIH Molecular Libraries Program. 2010</em></div></div></li><li class="brieflinkpopper two_line"><a class="brieflinkpopperctrl" href="/pubmed/21433394" ref="ordinalpos=1&amp;linkpos=3&amp;log$=relatedreviews&amp;logdbfrom=pubmed"><span xmlns:np="http://ncbi.gov/portal/XSLT/namespace" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" class="invert">Review</span> Discovery and development of a second highly selective M(1) Positive Allosteric Modulator (PAM).</a><span class="source">[Probe Reports from the NIH Mol...]</span><div class="brieflinkpop offscreen_noflow"><span xmlns:np="http://ncbi.gov/portal/XSLT/namespace" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" class="invert">Review</span> Discovery and development of a second highly selective M(1) Positive Allosteric Modulator (PAM).<div class="brieflinkpopdesc"><em xmlns:np="http://ncbi.gov/portal/XSLT/namespace" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" class="author">Bridges TM, Reid PR, Lewis LM, Dawson ES, Weaver CD, Wood MR, Lindsley CW. </em><em xmlns:np="http://ncbi.gov/portal/XSLT/namespace" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" class="cit">Probe Reports from the NIH Molecular Libraries Program. 2010</em></div></div></li><li class="brieflinkpopper two_line"><a class="brieflinkpopperctrl" href="/pubmed/34905693" ref="ordinalpos=1&amp;linkpos=4&amp;log$=relatedarticles&amp;logdbfrom=pubmed">Structural Features of Iperoxo-BQCA Muscarinic Acetylcholine Receptor Hybrid Ligands Determining Subtype Selectivity and Efficacy.</a><span class="source">[ACS Chem Neurosci. 2022]</span><div class="brieflinkpop offscreen_noflow">Structural Features of Iperoxo-BQCA Muscarinic Acetylcholine Receptor Hybrid Ligands Determining Subtype Selectivity and Efficacy.<div class="brieflinkpopdesc"><em xmlns:np="http://ncbi.gov/portal/XSLT/namespace" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" class="author">Wakeham MCL, Davie BJ, Chalmers DK, Christopoulos A, Capuano B, Valant C, Scammells PJ. </em><em xmlns:np="http://ncbi.gov/portal/XSLT/namespace" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" class="cit">ACS Chem Neurosci. 2022 Jan 5; 13(1):97-111. Epub 2021 Dec 14.</em></div></div></li><li class="brieflinkpopper two_line"><a class="brieflinkpopperctrl" href="/pubmed/21433387" ref="ordinalpos=1&amp;linkpos=5&amp;log$=relatedreviews&amp;logdbfrom=pubmed"><span xmlns:np="http://ncbi.gov/portal/XSLT/namespace" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" class="invert">Review</span> Discovery and development of the a highly selective M(1) Positive Allosteric Modulator (PAM).</a><span class="source">[Probe Reports from the NIH Mol...]</span><div class="brieflinkpop offscreen_noflow"><span xmlns:np="http://ncbi.gov/portal/XSLT/namespace" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" class="invert">Review</span> Discovery and development of the a highly selective M(1) Positive Allosteric Modulator (PAM).<div class="brieflinkpopdesc"><em xmlns:np="http://ncbi.gov/portal/XSLT/namespace" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" class="author">Bridges TM, Lewis LM, Dawson ES, Weaver CD, Lindsley CW. </em><em xmlns:np="http://ncbi.gov/portal/XSLT/namespace" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" class="cit">Probe Reports from the NIH Molecular Libraries Program. 2010</em></div></div></li></ul><a class="seemore" href="/sites/entrez?db=pubmed&amp;cmd=link&amp;linkname=pubmed_pubmed_reviews&amp;uid=21433383" ref="ordinalpos=1&amp;log$=relatedreviews_seeall&amp;logdbfrom=pubmed">See reviews...</a><a class="seemore" href="/sites/entrez?db=pubmed&amp;cmd=link&amp;linkname=pubmed_pubmed&amp;uid=21433383" ref="ordinalpos=1&amp;log$=relatedarticles_seeall&amp;logdbfrom=pubmed">See all...</a></div></div><div class="portlet"><div class="portlet_head"><div class="portlet_title"><h3><span>Recent Activity</span></h3></div><a name="Shutter" sid="1" href="#" class="portlet_shutter" title="Show/hide content" remembercollapsed="true" pgsec_name="recent_activity" id="Shutter"></a></div><div class="portlet_content"><div xmlns:np="http://ncbi.gov/portal/XSLT/namespace" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" id="HTDisplay" class=""><div class="action"><a href="javascript:historyDisplayState('ClearHT')">Clear</a><a href="javascript:historyDisplayState('HTOff')" class="HTOn">Turn Off</a><a href="javascript:historyDisplayState('HTOn')" class="HTOff">Turn On</a></div><ul id="activity"><li class="ra_rcd ralinkpopper two_line"><a class="htb ralinkpopperctrl" ref="log$=activity&amp;linkpos=1" href="/portal/utils/pageresolver.fcgi?recordid=67d66c0d2f30673f7bf8c470">Discovery of the first mAChR 5 (M5) selective ligand, an M5 Positive Allosteric ...</a><div class="ralinkpop offscreen_noflow">Discovery of the first mAChR 5 (M5) selective ligand, an M5 Positive Allosteric Modulator (PAM) - Probe Reports from the NIH Molecular Libraries Program<div class="brieflinkpopdesc"></div></div><div class="tertiary"></div></li><li class="ra_rcd ralinkpopper two_line"><a class="htb ralinkpopperctrl" ref="log$=activity&amp;linkpos=2" href="/portal/utils/pageresolver.fcgi?recordid=67d66c0d2f30673f7bf8be2e">High Throughput Screening Assays for NOD1 Inhibitors - Probe 1 - Probe Reports f...</a><div class="ralinkpop offscreen_noflow">High Throughput Screening Assays for NOD1 Inhibitors - Probe 1 - Probe Reports from the NIH Molecular Libraries Program<div class="brieflinkpopdesc"></div></div><div class="tertiary"></div></li><li class="ra_rcd ralinkpopper two_line"><a class="htb ralinkpopperctrl" ref="log$=activity&amp;linkpos=3" href="/portal/utils/pageresolver.fcgi?recordid=67d66c0b84f3725e592db1ad">Probe Development Efforts to Identify Novel Antagonists of the Sphingosine 1-pho...</a><div class="ralinkpop offscreen_noflow">Probe Development Efforts to Identify Novel Antagonists of the Sphingosine 1-phosphate Receptor 4 (S1P4) - Probe Reports from the NIH Molecular Libraries Program<div class="brieflinkpopdesc"></div></div><div class="tertiary"></div></li><li class="ra_rcd ralinkpopper two_line"><a class="htb ralinkpopperctrl" ref="log$=activity&amp;linkpos=4" href="/portal/utils/pageresolver.fcgi?recordid=67d66c0a67c23b31e0b37f73">A small molecule inhibitor of Caspase 1 - Probe Reports from the NIH Molecular L...</a><div class="ralinkpop offscreen_noflow">A small molecule inhibitor of Caspase 1 - Probe Reports from the NIH Molecular Libraries Program<div class="brieflinkpopdesc"></div></div><div class="tertiary"></div></li><li class="ra_rcd ralinkpopper two_line"><a class="htb ralinkpopperctrl" ref="log$=activity&amp;linkpos=5" href="/portal/utils/pageresolver.fcgi?recordid=67d66c092f30673f7bf8afca">A potent and selective small molecule Kir2.1 inhibitor - Probe Reports from the ...</a><div class="ralinkpop offscreen_noflow">A potent and selective small molecule Kir2.1 inhibitor - Probe Reports from the NIH Molecular Libraries Program<div class="brieflinkpopdesc"></div></div><div class="tertiary"></div></li></ul><p class="HTOn">Your browsing activity is empty.</p><p class="HTOff">Activity recording is turned off.</p><p id="turnOn" class="HTOff"><a href="javascript:historyDisplayState('HTOn')">Turn recording back on</a></p><a class="seemore" href="/sites/myncbi/recentactivity">See more...</a></div></div></div>
<!-- Custom content below discovery portlets -->
<div class="col7">
</div>
</div>
</div>
<!-- Custom content after all -->
<div class="col8">
</div>
<div class="col9">
</div>
<script type="text/javascript" src="/corehtml/pmc/js/jquery.scrollTo-1.4.2.js"></script>
<script type="text/javascript">
(function($){
$('.skiplink').each(function(i, item){
var href = $($(item).attr('href'));
href.attr('tabindex', '-1').addClass('skiptarget'); // ensure the target can receive focus
$(item).on('click', function(event){
event.preventDefault();
$.scrollTo(href, 0, {
onAfter: function(){
href.focus();
}
});
});
});
})(jQuery);
</script>
</div>
<div class="bottom">
<div id="NCBIFooter_dynamic">
<!--<component id="Breadcrumbs" label="breadcrumbs"/>
<component id="Breadcrumbs" label="helpdesk"/>-->
</div>
<div class="footer" id="footer">
<section class="icon-section">
<div id="icon-section-header" class="icon-section_header">Follow NCBI</div>
<div class="grid-container container">
<div class="icon-section_container">
<a class="footer-icon" id="footer_twitter" href="https://twitter.com/ncbi" aria-label="Twitter"><svg xmlns="http://www.w3.org/2000/svg" data-name="Layer 1" viewBox="0 0 300 300">
<defs>
<style>
.cls-11 {
fill: #737373;
}
</style>
</defs>
<title>Twitter</title>
<path class="cls-11" d="M250.11,105.48c-7,3.14-13,3.25-19.27.14,8.12-4.86,8.49-8.27,11.43-17.46a78.8,78.8,0,0,1-25,9.55,39.35,39.35,0,0,0-67,35.85,111.6,111.6,0,0,1-81-41.08A39.37,39.37,0,0,0,81.47,145a39.08,39.08,0,0,1-17.8-4.92c0,.17,0,.33,0,.5a39.32,39.32,0,0,0,31.53,38.54,39.26,39.26,0,0,1-17.75.68,39.37,39.37,0,0,0,36.72,27.3A79.07,79.07,0,0,1,56,223.34,111.31,111.31,0,0,0,116.22,241c72.3,0,111.83-59.9,111.83-111.84,0-1.71,0-3.4-.1-5.09C235.62,118.54,244.84,113.37,250.11,105.48Z">
</path>
</svg></a>
<a class="footer-icon" id="footer_facebook" href="https://www.facebook.com/ncbi.nlm" aria-label="Facebook"><svg xmlns="http://www.w3.org/2000/svg" data-name="Layer 1" viewBox="0 0 300 300">
<title>Facebook</title>
<path class="cls-11" d="M210.5,115.12H171.74V97.82c0-8.14,5.39-10,9.19-10h27.14V52l-39.32-.12c-35.66,0-42.42,26.68-42.42,43.77v19.48H99.09v36.32h27.24v109h45.41v-109h35Z">
</path>
</svg></a>
<a class="footer-icon" id="footer_linkedin" href="https://www.linkedin.com/company/ncbinlm" aria-label="LinkedIn"><svg xmlns="http://www.w3.org/2000/svg" data-name="Layer 1" viewBox="0 0 300 300">
<title>LinkedIn</title>
<path class="cls-11" d="M101.64,243.37H57.79v-114h43.85Zm-22-131.54h-.26c-13.25,0-21.82-10.36-21.82-21.76,0-11.65,8.84-21.15,22.33-21.15S101.7,78.72,102,90.38C102,101.77,93.4,111.83,79.63,111.83Zm100.93,52.61A17.54,17.54,0,0,0,163,182v61.39H119.18s.51-105.23,0-114H163v13a54.33,54.33,0,0,1,34.54-12.66c26,0,44.39,18.8,44.39,55.29v58.35H198.1V182A17.54,17.54,0,0,0,180.56,164.44Z">
</path>
</svg></a>
<a class="footer-icon" id="footer_github" href="https://github.com/ncbi" aria-label="GitHub"><svg xmlns="http://www.w3.org/2000/svg" data-name="Layer 1" viewBox="0 0 300 300">
<defs>
<style>
.cls-11,
.cls-12 {
fill: #737373;
}
.cls-11 {
fill-rule: evenodd;
}
</style>
</defs>
<title>GitHub</title>
<path class="cls-11" d="M151.36,47.28a105.76,105.76,0,0,0-33.43,206.1c5.28,1,7.22-2.3,7.22-5.09,0-2.52-.09-10.85-.14-19.69-29.42,6.4-35.63-12.48-35.63-12.48-4.81-12.22-11.74-15.47-11.74-15.47-9.59-6.56.73-6.43.73-6.43,10.61.75,16.21,10.9,16.21,10.9,9.43,16.17,24.73,11.49,30.77,8.79,1-6.83,3.69-11.5,6.71-14.14C108.57,197.1,83.88,188,83.88,147.51a40.92,40.92,0,0,1,10.9-28.39c-1.1-2.66-4.72-13.42,1-28,0,0,8.88-2.84,29.09,10.84a100.26,100.26,0,0,1,53,0C198,88.3,206.9,91.14,206.9,91.14c5.76,14.56,2.14,25.32,1,28a40.87,40.87,0,0,1,10.89,28.39c0,40.62-24.74,49.56-48.29,52.18,3.79,3.28,7.17,9.71,7.17,19.58,0,14.15-.12,25.54-.12,29,0,2.82,1.9,6.11,7.26,5.07A105.76,105.76,0,0,0,151.36,47.28Z">
</path>
<path class="cls-12" d="M85.66,199.12c-.23.52-1.06.68-1.81.32s-1.2-1.06-.95-1.59,1.06-.69,1.82-.33,1.21,1.07.94,1.6Zm-1.3-1">
</path>
<path class="cls-12" d="M90,203.89c-.51.47-1.49.25-2.16-.49a1.61,1.61,0,0,1-.31-2.19c.52-.47,1.47-.25,2.17.49s.82,1.72.3,2.19Zm-1-1.08">
</path>
<path class="cls-12" d="M94.12,210c-.65.46-1.71,0-2.37-.91s-.64-2.07,0-2.52,1.7,0,2.36.89.65,2.08,0,2.54Zm0,0"></path>
<path class="cls-12" d="M99.83,215.87c-.58.64-1.82.47-2.72-.41s-1.18-2.06-.6-2.7,1.83-.46,2.74.41,1.2,2.07.58,2.7Zm0,0">
</path>
<path class="cls-12" d="M107.71,219.29c-.26.82-1.45,1.2-2.64.85s-2-1.34-1.74-2.17,1.44-1.23,2.65-.85,2,1.32,1.73,2.17Zm0,0">
</path>
<path class="cls-12" d="M116.36,219.92c0,.87-1,1.59-2.24,1.61s-2.29-.68-2.3-1.54,1-1.59,2.26-1.61,2.28.67,2.28,1.54Zm0,0">
</path>
<path class="cls-12" d="M124.42,218.55c.15.85-.73,1.72-2,1.95s-2.37-.3-2.52-1.14.73-1.75,2-2,2.37.29,2.53,1.16Zm0,0"></path>
</svg></a>
<a class="footer-icon" id="footer_blog" href="https://ncbiinsights.ncbi.nlm.nih.gov/" aria-label="Blog">
<svg xmlns="http://www.w3.org/2000/svg" id="Layer_1" data-name="Layer 1" viewBox="0 0 40 40">
<defs><style>.cls-1{fill:#737373;}</style></defs>
<title>NCBI Insights Blog</title>
<path class="cls-1" d="M14,30a4,4,0,1,1-4-4,4,4,0,0,1,4,4Zm11,3A19,19,0,0,0,7.05,15a1,1,0,0,0-1,1v3a1,1,0,0,0,.93,1A14,14,0,0,1,20,33.07,1,1,0,0,0,21,34h3a1,1,0,0,0,1-1Zm9,0A28,28,0,0,0,7,6,1,1,0,0,0,6,7v3a1,1,0,0,0,1,1A23,23,0,0,1,29,33a1,1,0,0,0,1,1h3A1,1,0,0,0,34,33Z"></path>
</svg>
</a>
</div>
</div>
</section>
<section class="container-fluid bg-primary">
<div class="container pt-5">
<div class="row mt-3">
<div class="col-lg-3 col-12">
<p><a class="text-white" href="https://www.nlm.nih.gov/socialmedia/index.html">Connect with NLM</a></p>
<ul class="list-inline social_media">
<li class="list-inline-item"><a href="https://twitter.com/NLM_NIH" aria-label="Twitter" target="_blank" rel="noopener noreferrer"><svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" version="1.1" x="0px" y="0px" viewBox="0 0 249 249" style="enable-background:new 0 0 249 249;" xml:space="preserve">
<style type="text/css">
.st20 {
fill: #FFFFFF;
}
.st30 {
fill: none;
stroke: #FFFFFF;
stroke-width: 8;
stroke-miterlimit: 10;
}
</style>
<title>Twitter</title>
<g>
<g>
<g>
<path class="st20" d="M192.9,88.1c-5,2.2-9.2,2.3-13.6,0.1c5.7-3.4,6-5.8,8.1-12.3c-5.4,3.2-11.4,5.5-17.6,6.7 c-10.5-11.2-28.1-11.7-39.2-1.2c-7.2,6.8-10.2,16.9-8,26.5c-22.3-1.1-43.1-11.7-57.2-29C58,91.6,61.8,107.9,74,116 c-4.4-0.1-8.7-1.3-12.6-3.4c0,0.1,0,0.2,0,0.4c0,13.2,9.3,24.6,22.3,27.2c-4.1,1.1-8.4,1.3-12.5,0.5c3.6,11.3,14,19,25.9,19.3 c-11.6,9.1-26.4,13.2-41.1,11.5c12.7,8.1,27.4,12.5,42.5,12.5c51,0,78.9-42.2,78.9-78.9c0-1.2,0-2.4-0.1-3.6 C182.7,97.4,189.2,93.7,192.9,88.1z"></path>
</g>
</g>
<circle class="st30" cx="124.4" cy="128.8" r="108.2"></circle>
</g>
</svg></a></li>
<li class="list-inline-item"><a href="https://www.facebook.com/nationallibraryofmedicine" aria-label="Facebook" rel="noopener noreferrer" target="_blank">
<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" version="1.1" x="0px" y="0px" viewBox="0 0 249 249" style="enable-background:new 0 0 249 249;" xml:space="preserve">
<style type="text/css">
.st10 {
fill: #FFFFFF;
}
.st110 {
fill: none;
stroke: #FFFFFF;
stroke-width: 8;
stroke-miterlimit: 10;
}
</style>
<title>Facebook</title>
<g>
<g>
<path class="st10" d="M159,99.1h-24V88.4c0-5,3.3-6.2,5.7-6.2h16.8V60l-24.4-0.1c-22.1,0-26.2,16.5-26.2,27.1v12.1H90v22.5h16.9 v67.5H135v-67.5h21.7L159,99.1z"></path>
</g>
</g>
<circle class="st110" cx="123.6" cy="123.2" r="108.2"></circle>
</svg>
</a></li>
<li class="list-inline-item"><a href="https://www.youtube.com/user/NLMNIH" aria-label="Youtube" target="_blank" rel="noopener noreferrer"><svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" version="1.1" x="0px" y="0px" viewBox="0 0 249 249" style="enable-background:new 0 0 249 249;" xml:space="preserve">
<title>Youtube</title>
<style type="text/css">
.st4 {
fill: none;
stroke: #FFFFFF;
stroke-width: 8;
stroke-miterlimit: 10;
}
.st5 {
fill: #FFFFFF;
}
</style>
<circle class="st4" cx="124.2" cy="123.4" r="108.2"></circle>
<g transform="translate(0,-952.36218)">
<path class="st5" d="M88.4,1037.4c-10.4,0-18.7,8.3-18.7,18.7v40.1c0,10.4,8.3,18.7,18.7,18.7h72.1c10.4,0,18.7-8.3,18.7-18.7 v-40.1c0-10.4-8.3-18.7-18.7-18.7H88.4z M115.2,1058.8l29.4,17.4l-29.4,17.4V1058.8z"></path>
</g>
</svg></a></li>
</ul>
</div>
<div class="col-lg-3 col-12">
<p class="address_footer text-white">National Library of Medicine<br />
<a href="https://www.google.com/maps/place/8600+Rockville+Pike,+Bethesda,+MD+20894/@38.9959508,-77.101021,17z/data=!3m1!4b1!4m5!3m4!1s0x89b7c95e25765ddb:0x19156f88b27635b8!8m2!3d38.9959508!4d-77.0988323" class="text-white" target="_blank" rel="noopener noreferrer">8600 Rockville Pike<br />
Bethesda, MD 20894</a></p>
</div>
<div class="col-lg-3 col-12 centered-lg">
<p><a href="https://www.nlm.nih.gov/web_policies.html" class="text-white">Web Policies</a><br />
<a href="https://www.nih.gov/institutes-nih/nih-office-director/office-communications-public-liaison/freedom-information-act-office" class="text-white">FOIA</a><br />
<a href="https://www.hhs.gov/vulnerability-disclosure-policy/index.html" class="text-white" id="vdp">HHS Vulnerability Disclosure</a></p>
</div>
<div class="col-lg-3 col-12 centered-lg">
<p><a class="supportLink text-white" href="https://support.nlm.nih.gov/">Help</a><br />
<a href="https://www.nlm.nih.gov/accessibility.html" class="text-white">Accessibility</a><br />
<a href="https://www.nlm.nih.gov/careers/careers.html" class="text-white">Careers</a></p>
</div>
</div>
<div class="row">
<div class="col-lg-12 centered-lg">
<nav class="bottom-links">
<ul class="mt-3">
<li>
<a class="text-white" href="//www.nlm.nih.gov/">NLM</a>
</li>
<li>
<a class="text-white" href="https://www.nih.gov/">NIH</a>
</li>
<li>
<a class="text-white" href="https://www.hhs.gov/">HHS</a>
</li>
<li>
<a class="text-white" href="https://www.usa.gov/">USA.gov</a>
</li>
</ul>
</nav>
</div>
</div>
</div>
</section>
<script type="text/javascript" src="/portal/portal3rc.fcgi/rlib/js/InstrumentOmnitureBaseJS/InstrumentNCBIConfigJS/InstrumentNCBIBaseJS/InstrumentPageStarterJS.js?v=1"> </script>
<script type="text/javascript" src="/portal/portal3rc.fcgi/static/js/hfjs2.js"> </script>
</div>
</div>
</div>
<!--/.page-->
</div>
<!--/.wrap-->
</div><!-- /.twelve_col -->
</div>
<!-- /.grid -->
<span class="PAFAppResources"></span>
<!-- BESelector tab -->
<noscript><img alt="statistics" src="/stat?jsdisabled=true&amp;ncbi_db=books&amp;ncbi_pdid=book-part&amp;ncbi_acc=NBK50691&amp;ncbi_domain=mlprobe&amp;ncbi_report=record&amp;ncbi_type=fulltext&amp;ncbi_objectid=&amp;ncbi_pcid=/NBK50691/&amp;ncbi_pagename=Discovery of the first mAChR 5 (M5) selective ligand, an M5 Positive Allosteric Modulator (PAM) - Probe Reports from the NIH Molecular Libraries Program - NCBI Bookshelf&amp;ncbi_bookparttype=chapter&amp;ncbi_app=bookshelf" /></noscript>
<!-- usually for JS scripts at page bottom -->
<!--<component id="PageFixtures" label="styles"></component>-->
<!-- CE8B5AF87C7FFCB1_0191SID /projects/books/PBooks@9.11 portal107 v4.1.r689238 Tue, Oct 22 2024 16:10:51 -->
<span id="portal-csrf-token" style="display:none" data-token="CE8B5AF87C7FFCB1_0191SID"></span>
<script type="text/javascript" src="//static.pubmed.gov/portal/portal3rc.fcgi/4216699/js/3879255/4121861/3501987/4008961/3893018/3821238/4062932/4209313/4212053/4076480/3921943/3400083/3426610.js" snapshot="books"></script></body>
</html>