The effect of low-dose dopamine infusion on renal functions in hypotansive rats

Low-dose dopamine is commonly used to protect or improve renal function without causing systemic effects in patients with high risk of renal failure. In this study, our aim was to investigate the role of "renal" dose dopamine in protecting the renal functions in a rat model of hypotension. During the experiment rats were divided into four groups, each containing 10 rats: Control, hypotension, dopamine and hypotension plus dopamine groups. Dopamine was infused at a rate of 0.5 mcg/kg/min and hypotention was achieved by sodium-nitroprusside infusion of 40 mcg/kg/min. Blood and urinary samples were drawn for biochemical analysis during the two-hour study period. All rats were catheterised by femoral and carotid route for invasive monitoring and blood sampling. We did not observe any hemodynamic effect of dopamine at this rate of infusion. Blood urea levels increased during the study period in hypotension+dopamine groups. When these two groups were compared, BUN levels were found significantly higher in hypotension group during the early phase but the difference disappeared at the end of the study. Dopamine infusion had no effect on blood creatinine levels. Differences in potassium clearance were insignificant between the groups. Despite the significance of improved sodium clearance in the hypotensive rats treated with dopamine when compared with the other groups, natriuresis did not occured in the dopamine-only group As a conclusion, renal dose dopamine infusion at a rate of 0.5 mcg/kg/min, showed a short lived prevention against the increase of BUN during the early phase hypotension and it possessed a significant natriuretic action at this infusion rate. It is hard to mention about the protective effect of renal dose dopamine under the light of our study.