The Measurement of Cerebral Blood Flow in the Rat

Abstract

Cerebral blood flow (CBF) was determined in the rat under 70% nitrous oxide anesthesia and pentobarbital anesthesia. The application of the Fick principle technique of Kety et al. was modified utilizing ¹²³Xe infused intravenously steadily for 30 seconds, at which time the animal was decapitated and the head frozen in liquid nitrogen. A prior femoral artery to femoral vein shunt was led through a polyethylene catheter of 0.13 ml volume. This catheter passed as a coil in a Nal crystal well-counter with the arterial ¹³³Xe concentration curve recorded by a ratemeter-recordcr system. The results of the hemispheric blood flow (HBF) were: under 70% nitrous oxide anesthesia in normocapnia (Paco, 38 mm Hg), 86 ± 15 ml/100 gm per minute; with hypocapnia (Paco, 20 mm Hg), 40 ± 5 ml/100 gm per minute; with hypercapnia (Paco, 63 mm Hg), 187 ± 10 ml/100 gm per minute; and with pentobarbital anesthesia (Paco, 38 mm Hg), 41 ± 8 ml/100 gm per minute.