GPR18
<p ><b><i>N</i>-arachidonyl glycine receptor</b> also known as <b>G-protein coupled receptor 18</b> (GPR18) is a <a href="http://en.wikipedia.org/wiki/Protein" title="Protein" >protein</a> that in humans is encoded by the<i>GPR18</i> <a href="http://en.wikipedia.org/wiki/Gene" title="Gene" >gene</a>.<sup id="cite_ref-pmid9205118_0-0" class="reference" ><a href="http://en.wikipedia.org/wiki/GPR18#cite_note-pmid9205118-0" >[1]</a></sup><sup id="cite_ref-entrez_1-0" class="reference" ><a href="http://en.wikipedia.org/wiki/GPR18#cite_note-entrez-1" >[2]</a></sup> Along with the other previously "orphan" receptors<a href="http://en.wikipedia.org/wiki/GPR55" title="GPR55" >GPR55</a> and <a href="http://en.wikipedia.org/wiki/GPR119" title="GPR119" >GPR119</a>, GPR18 has been found to be a receptor for endogenous lipid neurotransmitters, several of which also bind to<a href="http://en.wikipedia.org/wiki/Cannabinoid_receptor" title="Cannabinoid receptor" >cannabinoid receptors</a>.<sup id="cite_ref-pmid16844083_2-0" class="reference" ><a href="http://en.wikipedia.org/wiki/GPR18#cite_note-pmid16844083-2" >[3]</a></sup><sup id="cite_ref-pmid18187165_3-0" class="reference" ><a href="http://en.wikipedia.org/wiki/GPR18#cite_note-pmid18187165-3" >[4]</a></sup><sup id="cite_ref-pmid19379823_4-0" class="reference" ><a href="http://en.wikipedia.org/wiki/GPR18#cite_note-pmid19379823-4" >[5]</a></sup>
<sup id="cite_ref-pmid19379823_4-0" class="reference" > </sup></p>
<p>
Recent research supports the hypothesis that GPR18 is the abnormal
cannabidiol receptor and <a href="http://en.wikipedia.org/wiki/N-arachidonoyl_glycine" title="N-arachidonoyl glycine" class="mw-redirect" >N-arachidonoyl glycine</a>, the endogenous lipid metabolite of <a href="http://en.wikipedia.org/wiki/Anandamide" title="Anandamide" >anandamide</a>, initiates directed <a href="http://en.wikipedia.org/wiki/Microglia" title="Microglia" >microglial</a> <a href="http://en.wikipedia.org/wiki/Cell_migration" title="Cell migration" >migration</a> in the CNS through activation of GPR18.<sup id="cite_ref-pmid20346144_5-0" class="reference" ><a href="http://en.wikipedia.org/wiki/GPR18#cite_note-pmid20346144-5" >[6]</a></sup></p>