title: Consistent unmasking of dopamine-induced dilation of the canine femoral vascular bed.
abstract: Dopamine (DA) produced dose-related vasodilation in the canine femoral vascular bed after the administration of two 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 approximately 1/25 as potent as DA in eliciting femoral vasodilation after yohimbine treatment. These findings suggest that 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.
mesh_terms: D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D004285:Dogs; D004298:Dopamine / Q000494:pharmacology*; D018492:Dopamine Antagonists; D004305:Dose-Response Relationship, Drug; D005260:Female; D005263:Femoral Artery / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects; D008297:Male; D010643:Phenoxybenzamine / Q000494:pharmacology; D011954:Receptors, Dopamine / Q000187:drug effects; D014664:Vasodilation / Q000187:drug effects*; D015016:Yohimbine / Q000494:pharmacology
chemical_list: D000317:Adrenergic alpha-Antagonists; D018492:Dopamine Antagonists; D011954:Receptors, Dopamine; D010643:Phenoxybenzamine; D015016:Yohimbine; D004298:Dopamine