Renal function in rats with innervated and denervated kidneys before and during sodium pentobarbital anesthesia

We have used a model for measuring renal clearances in the undisturbed rat to assess the role of the renal nerves in the depression of renal function during sodium pentobarbital anesthesia. One group of rats was studied with renal nerves intact and a second group was studied 7-9 days after bilateral renal denervation. Rats were prepared by placement of cannulae an average of 5 days prior to the clearance experiments. Renal function was measured before and after the injection of saline as the control vehicle and 2-3 days later, before, and after the injection of sodium pentobarbital (50 mg/kg) in the same rat. Sodium pentobarbital produced comparable decreases in glomerular filtration rate, para-aminohippuric acid clearance, urine flow rate, and sodium excretion in rats with denervated or innervated kidneys. Injection of saline resulted in no differences in measured variables between the rats with intact or sectioned renal nerves. Sodium pentobarbital caused a drop in arterial pressure in the denervated group but not in the innervated group. In a second series of experiments rats with denervated kidneys were implanted with an inflatable occluder around the aorta. This occluder was inflated to limit the drop in arterial pressure during anesthesia. When the blood pressure to the kidneys was maintained, renal function did not decrease during sodium pentobarbital anesthesia. These experiments suggest that the renal nerves are involved in the decrease in renal function during sodium pentobarbital anesthesia.