[Interaction of renin-angiotensin system inhibitors with dopamine in rat kidney]

Dopamine (1 mg/kg, s.c.) causes 2.2-fold increase in diuresis (p < 0.05) in anesthetized rats, which is accompanied by an increase in the urinary excretion of sodium and potassium by a factor of 2.2 and 2.8, respectively (p < 0.05). Preliminary administration of the ACE inhibitor enalapril (1 mg/kg, p.o., for 7 days) enhances the renal dopamine response with 3.5-fold increase in its diuretic effect and increases natriuresis 3.2 times and urine potassium excretion 5 times (p < 0.05). After preliminary introduction of the AT1-angiotensin receptor antagonist losartan (1 mg/kg, p.o., for 7 days) dopamine causes 3.3-fold increase in diuresis, 3.1-fold increase in natriuresis, and 3-fold increase in kaliuresis (p < 0.05). Preliminary administration of the direct renin inhibitor aliskiren (4 mg/kg, p.o., for 7 days) is accompanied by 6-fold increase in the diuretic effect of dopamine and increases natriuresis 7.2 times and urine potassium excretion 7 times (p < 0.05). It is concluded that renin-angiotensin system (RAS) of renal tissues is involved in the mechanism of dopamine action in the kidney, acting as a modulator that prevents excessive loss of water and electrolytes with urine.