VASOCONSTRICTOR MECHANISM OF 5-HYDROXYTRYPTAMINE IN ISOLATED AND PERFUSED CANINE BASILAR ARTERIES

  • 1 March 1987
    • journal article
    • research article
    • Vol. 286  (1) , 111-122
Abstract
The stainless steel cannula inserting method was applied to investigate the vasoconstrictor mechanism of 5-hydroxytryptamine (5-HT) in isolated and perfused canine basilar arteries. An intraluminal administration of 5-HT induced vasoconstriction in a dose-dependent manner. Pretreatment with ketanserin, a specific 5-HT2 inhibitor, and with methysergide, a mixed 5-HT inhibitor blocked the vasoconstriction induced by 5-HT. Pretreatment with diltiazem, a potent calcium antagonist, also definitely depressed the vasoconstriction by 5-HT, as well as that by potassium chloride (KCl). The endothelial removal by intraluminal saponin treatment little influenced vasoconstriction by 5-HT. It is concluded that 5-HT-induced vasoconstriction of canine basilar arteries may be in part due to the stimulation of 5-HT2 receptors, which activate an intracellualr calcium movement, rather than the influx from the extracellular space.