Abstract
To evaluate the effect of selective brain cooling on cortical cerebral blood flow, we reduced brain temperature in nitrous oxide anesthetized adult rats using a high speed fan while keeping rectal temperature at 37-38 degrees C. During selective brain cooling, cortical cerebral blood flow, as measured by laser-Doppler flowmetry, increased to 215 +/- 26% (mean +/- SE) of baseline at a cortical brain temperature of 30.9 +/- 0.5 degrees C and a rectal temperature of 37.5 +/- 0.1 degrees C. During rewarming, as brain temperature increased, cortical cerebral blood flow decreased. The cerebral vasodilatory response to hypothermia may explain its protective effects during and after cerebral ischemia.
