AJP - Heart and Circulatory Physiology, Vol 250, Issue 2 304-H312, Copyright © 1986 by American Physiological Society
A venous outflow method for continuously monitoring cerebral blood flow in the rat
S. Morii, A. C. Ngai, K. R. Ko and H. R. Winn
We analyzed the retroglenoid venous outflow (VOF) technique in the rat to
document the validity of this method of measuring cerebral blood flow
(CBF). Stereotypic changes in CBF were obtained with VOF during hypercarbia
and hypotension. O2 content of retroglenoid venous blood did not differ
significantly from O2 content of blood obtained from the sagittal sinus,
suggesting minimal extracerebral contamination of the retroglenoid venous
blood. This lack of extracerebral contamination was further analyzed using
a double tracer technique (125I-labeled serum albumin, 22Na) that
quantitated minimal extracerebral contamination in the retroglenoid vein.
CBF measurements were made simultaneously using microsphere and VOF
methods, and excellent correlation was found between the two techniques
over a wide range of CBF during normoxia, hypoxia, and normoxic hypocarbia
and hypercarbia. However, a decrease in the ratio of VOF to microsphere CBF
was observed during severe normoxic hypotension (mean arterial pressure =
41 +/- 4 mmHg). VOF represented 18% of total CBF as measured by microsphere
method. This study indicates that the retroglenoid outflow technique in
rats is a valid method of measuring CBF.
