Measurement of the dynamics of the cerebrospinal fluid system in the rat.

A technique for intracranial pressure (ICP) monitoring in the rat that enables the measurement of the cerebrospinal outflow resistance (RCSF) and the intracranial pressure-volume index (PVI) is described. A permanent catheter placed into the cisterna magna through the occipital bone was used. ICP, RCF and PVI were measured in ten LEW rats. The baseline ICP was 8 +/- 1.7 mm Hg (Mean +/- S.D.). The PVI was 0.0518 +/- 0.018 ml. The RCSF was 464 +/- 196 mm Hg ml-1 min-1 which is less than reported previously. The cannulation technique easy and gives reliable pressure tracings. It enables ICP monitoring and estimation of the dynamics of the cerebrospinal fluid (CSF) system during experimental surgical procedures in the rat.