Ketanserin causes surmountable antagonism of 5-hydroxytryptamine-induced contractions of large coronary arteries of dog.
Large coronary arteries of the dog were contracted with 5-hydroxytryptamine (5-HT). The 5-HT2-receptor antagonist ketanserin antagonized the 5-HT-induced effects. Unlike Brazenor and Angus (Europ J Pharmacol 81:569-576, 1982) who reported insurmountable antagonism of the effects of 5-HT in dog coronaries, we found that the antagonism by ketanserin can be surmounted, provided the concentrations of 5-HT are high enough. Ketanserin also unmasked a saturable component of the 5-HT-induced contractions. Although ketanserin (0.1-1 mumol/l) depressed the maximal force of the saturable component, it did not change its EC50 (-log mol/l 8.0). We conclude that large coronary arteries of dog are contracted by 5-HT mainly through 5-HT2-receptors and to a smaller extent through receptors different from 5-HT2.
Frenken
M
M
Kaumann
A J
AJ
D000818:Animals; D003331:Coronary Vessels / Q000187:drug effects*; D004285:Dogs; D005260:Female; D066298:In Vitro Techniques; D007650:Ketanserin; D008297:Male; D010880:Piperidines / Q000494:pharmacology*; D011985:Receptors, Serotonin / Q000187:drug effects; D012701:Serotonin / Q000494:pharmacology*; D012702:Serotonin Antagonists / Q000494:pharmacology*; D014661:Vasoconstriction / Q000187:drug effects*
D010880:Piperidines; D011985:Receptors, Serotonin; D012702:Serotonin Antagonists; D012701:Serotonin; D007650:Ketanserin