DOPAMINE ANTAGONIST EFFECT OF VERAPAMIL ON ISOLATED PERFUSED RABBIT EAR ARTERY

  • 1 January 1983
    • journal article
    • research article
    • Vol. 226  (3) , 802-805
Abstract
Rabbit ear arteries were isolated and perfused with Krebs-bicarbonate solution. Brief periods of supramaximal nerve stimulation caused reproducible constriction of the arteries, which was inhibited by dopamine at concentrations ranging from 3.3 .times. 10-9 to 3.3 .times. 10-7 M. The inhibitory effect of dopamine was antagonized by sulpiride and by verapamil. The dose-response curve to dopamine was shifted to the right by both sulpiride and verapamil, indicative of competitive inhibition. The dopamine antagonist activity of verapamil does not appear to be a consequence of its Ca channel inhibitory activity because other Ca2+ antagonists (e.g., nitrendipine and diltiazem) had no similar action.