Blocking Effects of Nipradilol on Vasoconstrictor Responses to Periarterial Nerve Stimulation and α-Adrenoceptor Agonists in Isolated and Perfused Canine Mesenteric Arteries

Abstract

The stainless steel cannula inserting method was used to observe effects of nipradilol and prazosin on responses to periarterial electrical nerve stimulation and intraluminal administration of noradrenaline or phenylephrine in isolated and perfused canine mesenteric arteries. With small doses, nipradilol slightly potentiated vasoconstrictor responses to noradrenaline, but not periarterial stimulation. With a relatively large dose, nipradilol almost uniformly suppressed both periarterial stimulation-induced and noradrenaline- or phenylephrine-induced vasoconstriction. On the other hand, prazosin inhibited noradrenaline-induced vasoconstriction at small doses but not periarterial nerve stimulation-induced vasoconstrictions. At any doses, prazosin strongly inhibited noradrenaline-induced constrictions more markedly than periarterial stimulation-induced constrictions. It is concluded that nipradilol has a dominant inhibitory property on periarterial nerve stimulation-induced constriction in isolated canine mesenteric arteries.

Effects of Nipradilol on Alpha-Adrenoceptor Function in Ocular Arteries

“…· 1 -Adrenoceptor-blocking potencies of nipradilol did not differ between dog ocular arteries used in the present study. · 1 -and ß-adrenoceptor-blocking activities of nipradilol have also been reported in isolated peripheral arteries [20,21] and in the systemic circulation of anesthetized animals [22].…”