RT Journal Article SR Electronic T1 Serotonin Receptor Binding Sites Affected Differentially by Guanine Nucleotides JF Molecular Pharmacology JO Mol Pharmacol FD American Society for Pharmacology and Experimental Therapeutics SP 700 OP 708 VO 16 IS 3 A1 STEPHEN J. PEROUTKA A1 RICHARD M. LEBOVITZ A1 SOLOMON H. SNYDER YR 1979 UL http://molpharm.aspetjournals.org/content/16/3/700.abstract AB Guanosine triphosphate (GTP) and diphosphate (GDP) decrease the binding of the agonist [3H]serotonin (5-HT) to serotonin receptors in mammalian brain membranes. Binding of the antagonist [3H]spiroperidol is not affected by guanine nucleotides while the mixed agonist-antagonist [3H]lysergic acid diethylamide ([3H]LSD) is affected in an intermediate manner. GTP lowers the apparent affinity of [3H]5-HT for its receptors without changing the number of binding sites. Both the association and dissociation rates of [3H]5-HT are increased by GTP. The potency of 5-HT agonists in competing for [3H]5-HT but not [3H]LSD or [3H]spiroperidol binding sites is decreased by GTP. Competition by partial agonists and antagonists for [3H]5-HT binding sites is not affected by GTP. ACKNOWLEDGMENTS We thank Pamela Morgan for manuscript preparation.