title: Antagonism by droperidol of dopamine-induced relaxation in isolated dog arteries.
abstract: Dopamine caused a dose-related relaxation in helically cut strips of dog coronary and renal arteries treated with phenoxybenzamine andcontracted with prostaglandin F2 alpha. The dose-response curve to dopamine was shifted to the right by droperidol in concentrations above 3 X 10(-5) M. Adenosine-induced relaxations were not attenuated by droperidol. The dose--relaxation curve to isoproterenol was also shifted to the right by droperidol. Propranolol (10(-6) M) failed to significantly alter the dose response curve to dopamine, and in propranolol-treated preparations the antagonism by droperidol of dopamine actions was practically identical with that in control preparations. Droperidol appears to act as a reversible, surmountable antagonist to dopamine actions on dog arterial smooth muscles, and such evidence supports the hypothesis of specific dopamine receptors in dog arteries.
mesh_terms: D000818:Animals; D003331:Coronary Vessels / Q000187:drug effects; D004285:Dogs; D004298:Dopamine / Q000494:pharmacology; D018492:Dopamine Antagonists; D004329:Droperidol / Q000494:pharmacology*; D004347:Drug Interactions; D005260:Female; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D009126:Muscle Relaxation / Q000187:drug effects*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D011433:Propranolol / Q000494:pharmacology
chemical_list: D018492:Dopamine Antagonists; D011433:Propranolol; D007545:Isoproterenol; D004329:Droperidol; D004298:Dopamine