AJP - Regulatory, Integrative and Comparative Physiology, Vol 251, Issue 5 996-R999, Copyright © 1986 by American Physiological Society
Closed ventriculocisternal perfusion to determine CSF production rate and pressure
A. A. Artru and T. F. Hornbein
When the rate of cerebrospinal fluid (CSF) production (Vf) is determined
using the classical open ventriculocisternal perfusion technique, it is not
possible to observe natural fluctuations in CSF pressure, or the effects of
experimental treatments on CSF pressure, or to make inferences about CSF
volume or resistance to reabsorption of CSF, because CSF pressure is fixed
according to the level of the distal end of the cisternal outflow cannula.
In addition, the convention of placing the distal end of the cisternal
outflow cannula at the interaural line fixes CSF pressure at a value that
may not be usual for the animal, thereby introducing potential causes for
error in the determination of Vf. The present study describes and evaluates
a method of closed ventriculocisternal perfusion that allows the
simultaneous determination of Vf and CSF pressure. With this method the
time to tracer equilibration was less, and the volume of distribution of
the tracer was smaller than with the classical open perfusion system. CSF
pressure tracings were of high fidelity showing both respiratory and
cardiovascular variation. During both sedation with nitrous oxide or
halothane anesthesia, Vf values using closed perfusion were similar to
values previously reported using open perfusion. Vf decreased during
halothane anesthesia compared with nitrous oxide sedation. No time-related
change in Vf from the first measurable time period (approximately 2 h) to
the end of the study (approximately 5 h) was observed.
