Further characterization of the 5-hydroxytryptamine 5-HT1-like receptor mediating contraction of guinea-pig iliac artery.
We recently described a 5-hydroxytryptamine 5-HT1-like receptor mediating contraction in guinea-pig isolated iliac artery. The present study was aimed at characterizing this receptor with respect to the currently recognized 5-HT1 receptor subtypes (5-HT1A, 5-HT1B, 5-HT1C and 5-HT1D). The potencies of 13 drugs tested as agonists correlated with their affinities for 5-HT1D binding sites only. The concentration-response curve for 5-carboxamidotryptamine (5-CT, a 5-HT1-like receptor agonist) was unaffected by propranolol (10 microM), which is reported to have affinity for 5-HT1A, 5-HT1B and 5-HT1C recognition sites. Yohimbine (3 microM) and metergoline (1 microM) antagonized 5-CT with pKB values of 6.15 and 6.96, respectively. These values are close to those found in a functional correlate of 5-HT1D sites in the same species, namely the presynaptic 5-HT autoreceptor in guinea-pig brain cortex. The overall results support the view that the receptor studied is of the 5-HT1D subtype. The receptor shares close similarities with other vascular 5-HT1-like receptors mediating contraction, for example the receptor present in dog saphenous vein.
Schoeffter
P
P
Sandoz Pharma Ltd., Basel, Switzerland.
Sahin-Erdemli
I
I
D000818:Animals; D001665:Binding Sites; D006168:Guinea Pigs; D007083:Iliac Artery / Q000187:drug effects / Q000502:physiology*; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects; D011985:Receptors, Serotonin / Q000502:physiology*; D012701:Serotonin / Q000378:metabolism / Q000494:pharmacology*; D012702:Serotonin Antagonists / Q000494:pharmacology*; D017366:Serotonin Receptor Agonists / Q000494:pharmacology*; D014661:Vasoconstriction / Q000187:drug effects
D011985:Receptors, Serotonin; D012702:Serotonin Antagonists; D017366:Serotonin Receptor Agonists; D012701:Serotonin