title: Dopamine receptor blockade does not affect the natriuresis accompanying sodium chloride infusion in dogs.
abstract: Intravenous (IV) saline infusions cause parallel increments in urinary excretion of dopamine (DA) and sodium. Exogenous administration of DA exerts a natriuretic effect by action on DA receptors. The possibility that DA mediates the natriuretic response to saline infusion was studied by infusing 0.9% saline solution IV (60 ml/kg) in conscious dogs with and without selective blockade of DA1 and DA2 receptors. With no antagonist, the total increase in sodium excretion during the 120-minute saline infusion and the 60 minutes after the saline infusion was 99.5 +/- 7.6 mmol. The increase in total sodium excretion was not affected by IV infusion of the selective DA1 antagonist SCH 23390 in doses of 0.5 micrograms/kg/min and 5 micrograms/kg/min. The total increment in sodium excretion produced by saline was also unaltered by large doses (1 micrograms/kg/min and 10 micrograms/kg/min) of the selective DA2 antagonist domperidone. Our results do not support a role of DA as a mediator of saline-induced natriuresis in the dog.
mesh_terms: D000818:Animals; D001552:Benzazepines / Q000494:pharmacology; D004285:Dogs; D004294:Domperidone / Q000494:pharmacology; D004298:Dopamine / Q000494:pharmacology*; D005260:Female; D009318:Natriuresis / Q000187:drug effects*; D011954:Receptors, Dopamine / Q000187:drug effects / Q000502:physiology*; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; D012965:Sodium Chloride / Q000494:pharmacology*
chemical_list: D001552:Benzazepines; D011954:Receptors, Dopamine; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; D012965:Sodium Chloride; D004294:Domperidone; D004298:Dopamine