The Kety Schmidt washout technique has been modified to measure whole brain blood flow and metabolism in the rat. During nitrous oxide anesthesia, 14 rats exhaled 133Xe, and continuous and simultaneous arterial and cerebral venous samples were drawn from a femoral artery and the transverse sinus of the brain. Extracerebral contamination of the venous sample was minimal, and equilibration of 133Xe in brain tissue and blood was obtained after 10-24 min of inhalation. Cerebral blood flow was calculated from the total activity of the mechanically integrated arterial and venous samples according to the principle of Scheinberg and Stead. At a mean PaCO2 of 40 mmHg, CBF averaged 98 ± 6 (SEM) ml/100 gxmin and CMRO2 averaged 5.4 ± 0.7 (SEM) ml/100 gxmin. CBF changed 2.4% with each millimeter Hg change of PaCO2 while CMRO2 changed only insignificantly. The values obtained for CBF are higher than reported for man and large laboratory animals but reflect the proportionately greater amount of gray matter in the rat brain.
ASJC Scopus subject areas
- Physiology (medical)