Effect of ibopamine on diuresis and arterial blood pressure in anesthetized rats and its interactions with dopaminergic and alpha- and beta-adrenergic antagonists.

The present paper reports a study of the effect of ibopamine (SB-7505), the 3,4-diisobutyryl ester of N-methyldopamine (epinine), on diuresis and blood pressure in anesthetized rats. The results obtained demonstrate that ibopamine, administered orally at doses of 12.5 to 200 mg/kg, caused a dose-dependent diuresis. The increase in blood pressure was moderate and of short duration. The diuretic effect of ibopamine was antagonized by d-sulpiride, haloperidol, bulbocapnine and phenoxybenzamine, but not by l-sulpiride and l-propranolol. The increase in blood pressure was antagonized by phenoxybenzamine only. The diuretic effect of ibopamine in rats reflects agonist activity at dopamine receptors and, in part, alpha-adrenoceptors and is independent of beta-adrenoceptors.