EXPERIMENTS ON ACTION MECHANISM OF VASCULAR SPASMOLYTIC AGENTS .1. ACTION OF NITROPRUSSIDE SODIUM, NITROGLYCEROL, PRENYLAMINE, AND VERAPAMIL ON ARRESTED POTASSIUM CONTRACTURE OF ISOLATED CORONARY-ARTERIES

  • 1 January 1976
    • journal article
    • research article
    • Vol. 35  (10) , 1347-1358
Abstract
In the K contraction of isolated coronary arteries of cattle, the relaxation effected by Ca depletion can be blocked by La ions. The contraction persisting in Ca-free solution (arrested K contraction was used to differentiate the sites of attack of spasmolytics. Verapamil and prenylamine were ineffective in this contraction model. By contrast, nitroprusside sodium and nitroglycerol act spasmolytically. Both groups of drugs act through basically different sites. The findings, were consistent with the hypothesis that the spasmolytic action of verapamil and prenylamine is based on blockade of Ca influ. For nitroprusside sodium and nitroglycerol, the mechanism on arrested K contraction was ruled out.