125I-lysergic acid diethylamide binds to a novel serotonergic site on rat choroid plexus epithelial cells.
125I-Lysergic acid diethylamide (125I-LSD) binds with high affinity to serotonergic sites on rat choroid plexus. These sites were localized to choroid plexus epithelial cells by use of a novel high resolution stripping film technique for light microscopic autoradiography. In membrane preparations from rat choroid plexus, the serotonergic site density was 3100 fmol/mg of protein, which is 10-fold higher than the density of any other serotonergic site in brain homogenates. The choroid plexus site exhibits a novel pharmacology that does not match the properties of 5-hydroxytryptamine-1a (5-HT1a), 5-HT1b, or 5-HT2 serotonergic sites. 125I-LSD binding to the choroid plexus site is potently inhibited by mianserin, serotonin, and (+)-LSD. Other serotonergic, dopaminergic, and adrenergic agonists and antagonists exhibit moderate to weak affinities for this site. The rat choroid plexus 125I-LSD binding site appears to represent a new type of serotonergic site which is located on non-neuronal cells in this tissue.
D000818:Animals; D001345:Autoradiography; D001665:Binding Sites; D001921:Brain / Q000378:metabolism; D002417:Cattle; D002831:Choroid Plexus / Q000378:metabolism*; D004847:Epithelial Cells; D004848:Epithelium / Q000378:metabolism; D007457:Iodine Radioisotopes; D008238:Lysergic Acid Diethylamide / Q000378:metabolism*; D051379:Mice; D011817:Rabbits; D051381:Rats; D012701:Serotonin / Q000378:metabolism*; D013552:Swine
D007457:Iodine Radioisotopes; D012701:Serotonin; D008238:Lysergic Acid Diethylamide