title: Selective DA2 versus DA1 antagonist activity of domperidone in the periphery.
abstract: Relative activity of domperidone as an antagonist of the two peripheral dopamine (DA) receptors, DA1 and DA2, was studied in pentobarbital-anesthetized dogs. Renal vasodilation produced by intra-arterial injection of DA into the phenoxybenzamine-pretreated renal vascular bed was the DA1-mediated response, while femoral vasodilation induced by dipropyl dopamine injected into the femoral artery with intact nerve supply was the DA2-mediated response. Domperidone, 0.5-5 micrograms/kg intravenously, inhibited the DA2 response by 15-75%. In contrast, doses up to 5 mg/kg had no effect on DA1-mediated or bradykinin-induced renal vasodilation. Domperidone has thus proved to be more selective than other DA2 antagonists, differentiating between the two peripheral DA receptors by a margin of greater than 10(4). Furthermore, domperidone was found to be selective as a DA2 versus alpha 2-adrenergic antagonist as studied on the dog cardioaccelerator nerve, thus, enhancing its value as a selective DA2 antagonist.
mesh_terms: D000818:Animals; D001920:Bradykinin / Q000494:pharmacology; D004285:Dogs; D004294:Domperidone / Q000494:pharmacology*; D004298:Dopamine / Q000031:analogs & derivatives / Q000494:pharmacology; D004558:Electric Stimulation; D010643:Phenoxybenzamine / Q000494:pharmacology; D011954:Receptors, Dopamine / Q000187:drug effects*; D012039:Regional Blood Flow / Q000187:drug effects; D012079:Renal Circulation / Q000187:drug effects
chemical_list: D011954:Receptors, Dopamine; D010643:Phenoxybenzamine; D004294:Domperidone; C020895:N,N-di-n-propyldopamine; D001920:Bradykinin; D004298:Dopamine