A pharmacological analysis of the rat spinal cord serotonin (5-HT) autoreceptor.
The pharmacological characteristics of the presynaptic 5-HT receptor associated with the modulation of 5-HT release were investigated in a preparation of rat spinal cord synaptosomes (nerve terminals) superfused with a Tris-buffered Krebs solution containing fluoxetine (1 microM). The 5-HT receptor agonists serotonin (1-100 nM), lysergic acid diethylamide (10 nM-1 microM) and the 5-HT1B receptor agonists 1-(m-trifluoromethylphenyl)piperazine (100 nM-1 microM) and 1-(m-chlorophenyl) piperazine (100 nM-3 microM) concentration dependently decreased [3H]5-HT release, while 8-hydroxy-2-(di-n-propylamino)tetralin, a selective 5-HT1A receptor agonist, was inactive. The actions of the effective agonists were reversed by quipazine, an antagonist with high affinity for 5-HT1B binding sites, but not by spiperone, a 5-HT1A receptor antagonist. Furthermore, mesulergine, a 5-HT1C receptor antagonist was ineffective in reversing the action of 5-HT on [3H]5-HT release. These data indicate that the rat spinal cord nerve terminal autoreceptor has characteristics similar to the 5-HT1B binding site.
Brown
L
L
Department of Pharmacology and Toxicology, West Virginia University Medical Center, Morgantown 26506.
Amedro
J
J
Williams
G
G
Smith
D
D
D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D000818:Animals; D004873:Ergolines / Q000494:pharmacology; D008297:Male; D010879:Piperazines / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology; D011814:Quipazine / Q000494:pharmacology; D051381:Rats; D011985:Receptors, Serotonin / Q000187:drug effects*; D012701:Serotonin / Q000378:metabolism; D013116:Spinal Cord / Q000187:drug effects*; D013134:Spiperone / Q000494:pharmacology; D013764:Tetrahydronaphthalenes / Q000494:pharmacology; D014316:Tritium
D004873:Ergolines; D010879:Piperazines; D011985:Receptors, Serotonin; D013764:Tetrahydronaphthalenes; D014316:Tritium; C018406:1-(3-trifluoromethylphenyl)piperazine; D012701:Serotonin; D011814:Quipazine; D013134:Spiperone; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D011188:Potassium; C031649:mesulergine