Abstract: Glomerular filtration rate (creatinine clearance) and renal blood flow (PAH clearance) were determined in dogs anesthetized with chloralose or Na-pentobarbital. In the control group (10 dogs), the renal hemodynamic effects did not show any significant changes in 2 hours. In the medicated group (10 dogs), after an intravenous injection of the alkaloid 0.25 mg/kg, there appeared a prompt hypotension, oliguria, a reduction of GFR and RBF, but no change in the glomerular filtration fraction. The renal vascular resistance increased. Since these renal, hemodynamic alterations were found to be closely parallel to the modifications of blood pressure, they might also be a temporary depression secondary to the acute hypotension.