A method of constant-rate perfusion for studying the renal vascular resistance of rats

The renal vascular resistances of rats were measured on the constant-rate perfusion preparations. By catherizing the abdominal aorta above and below the origin of the renal artery, the extracorporeal circulation of kidneys was driven by a constant-speed pump. The blood pressure distal to the pump was taken as a measure of local vascular resistance. After ligation of superior mesenteric artery, the results represented solely the vascular resistance of the renal arteries. Drug could also be administered intra-arterially by injecting them into the perfusing system in order to expose any direct action.
The validity of the method was examined by clonidine, N-methyltyramine and dopamine. The hemodynamic changes in rats matched to those in dogs.