CONSISTENT UNMASKING OF DOPAMINE-INDUCED DILATION OF THE CANINE FEMORAL VASCULAR BED

  • 1 January 1980
    • journal article
    • research article
    • Vol. 215  (3) , 662-667
Abstract
Dopamine (DA) produced dose-related vasodilation in the canine femoral vascular bed after the administration of 2 .alpha. adrenergic blocking agents, WR 149,024 (1,18-diamino-6,13-diaza-9,10-dithiaoctadecane) or yohimbine. DA-induced vasodilation unmasked by yohimbine was not antagonized by propranolol, pyrilamine and metiamide, hexamethonium or atropine, but was attenuated selectively by the DA antagonist sulpiride. The R-enantiomer of sulpiride was more effective than the S-enantiomer in attenuating DA-induced dilation. Phenoxybenzamine produced moderate (apparently nonspecific) attenuation of vasodilator responses to DA. The weaker vascular DA agonist, N,N-di-n-propyl dopamine, was .apprx. 1/25 as potent as DA in eliciting femoral vasodilation after yohimbine treatment. DA produces femoral vasodilation after WR 149,024 or yohimbine by activation of vascular DA receptors similar to those proposed to exist in the renal vascular bed.