Abstract

We reported recently the molecular cloning of a genomic fragment, designated S31, that has an open reading frame of 1095 nucleotides, encoding a protein of 365 amino acids. Amino acid similarity analysis suggested that the S31 protein could be a guanine nucleotide-binding protein-coupled receptor pertaining to the serotonin receptor subfamily. Expression of the S31 open reading frame in murine L cells confirmed this, because it led to the appearance of serotonin-mediated inhibition of adenylyl cyclase activity, which was absent in the recipient L cells. We now report some aspects of the pharmacological profile of this receptor. We found that the relative potencies with which 5-hydroxytryptamine, 5-carboxamidotryptamine, methysergide, ergotamine, 8-hydroxydipropylaminotetralin, and trifluoromethylphenylpiperazine promote inhibition of adenylyl cyclase are as follows: 5-hydroxytryptamine > methysergide > ergotamine > trifluoromethylphenylpiperazine > or = 8-hydroxydipropylaminotetralin > 5-carboxyamidotryptamine. This corresponds to the rank order of potencies assigned for these drugs for the 1E subtype of serotonin receptors discovered by Leonhardt and collaborators in human brain [J. Neurochem. 53:465-471 (1989)].