Effect of Quinidine upon the Vascular Response to Norepinephrine in the Dog Forelimb

Abstract

Summary

Quinidine was shown not to affect the vascular response to KCl, MgCl₂, CaCl₂, or acetylcholine in the dog forelimb. Quinidine did greatly inhibit at therapeutic and nonvasodilating levels, the slow phase of the norepinephrine vasoconstrictor response. It is therefore concluded that the adrenergic inhibition of quinidine, reported here and by others, is mainly the result of an effect at the sarcolemma of the vascular smooth muscle cell which inhibits calcium influx and hence vasoconstriction.