Cerebral blood flow and oxygen consumption in rat, measured with microspheres or xenon

The cerebral blood flow and, in some rats, the cerebral rate of oxygen consumption were measured in three groups of male rats. Fractionation of radioisotope-labeled microspheres was used to measure regional cerebral blood flow in four parts of the rat brain. The arterial and cerebral venous concentrations of radioactive xenon during desaturation were used to measure the blood flow and oxygen consumption of cortex when venous blood was collected from the superior sagittal sinus, or of whole brain when the transverse sinus was sampled. The regional cerebral flow measured with microspheres had a large standard error reflecting the technical difficulty of this method. The cerebral blood flow measured with xenon was higher when venous blood was sampled from the superior sagittal sinus than when sampled from the transverse sinus, but cerebral oxygen consumption rates were similar. The difference reflects the greater trauma involved in the superior sagittal approach and possible extracerebral contamination present in the transverse sinus approach.