Subclassification of presynaptic 5-HT autoreceptors in the human cerebral cortex as 5-HT1Dβreceptors

✍ Scribed by K. Fink; M. Göthert; J. Zentner

• Publisher: Springer-Verlag
• Year: 1995
• Tongue: English
• Weight: 410 KB
• Volume: 352
• Category: Article
• ISSN: 0028-1298
• DOI: 10.1007/bf00172785

✦ Synopsis

Human cerebral cortical synaptosomes were used to determine the 5-hydroxytryptamine (5-HT) receptor subtype to which the inhibitory presynaptic 5-HT autoreceptor belongs. The synaptosomes preincubated with [3H~5-HT were superfused and tritium overflow was stimulated by high K +. The K +-evoked tritium overflow, which was Ca 2 +-dependent but tetrodotoxin-resistant, was concentration-dependently inhibited by the nonselective 5-HT~D~/1D~ receptor agonist, 5-carboxamidotryptamine. Ketanserin at a concentration which should block the 5-HT~D~ but not the 5-HT1D~ receptor failed to antagonize the inhibitory effect of 5-carboxamidotryptamine. In contrast, the nonselective 5-HTm~/~D~ receptor antagonist, methiothepin, at a concentration which should block both the 5-HT~D~ and the 5-HT~D~ receptor abolished the effect of 5-carb0xamidotryptamine. It is concluded that the presynaptic 5-HT autoreceptor, which has previously been classified as 5-HT~D, belongs to the 5-HT1D~ subtype.