An Attempt to Measure the Two‐Way Permeability in the Blood‐Brain‐CSF System

Abstract

EDSTROY, R. An attempt to measure the two-way permeabiliu in the blood-brain-CSFsystem. Acta physiol. scand 1964.61.2 12-2 18. -Perfision ofvarious CSF (cerebrospinal fluid) spaces with an artificial fluid opens the way to a quantitative analysis of transport rates and permeability in the blood-CSF interphase. Several approaches have been reported recently; two of the most successful ones are the reports of Heisey et al. (1962) and Pollay and Davson (1963). In these studies the CSF-blood transfer has been calculated from measured losses of indicator material from the perfision fluid. The present paper will report on an attempt to amplify this approach by a determination also of the appearance rate of the indicator material in the blood, and by a simultaneous measurement of the transport rate in the opposite direction: blood-CSF.Various equations for use in this system are given, and practical experiments with sodium and iodide transfer are reported. They do not permit a conclusion of any preferential direction of sodium transport, but iodide seems to be transported about 10 times faster out of the cerebral ventricles than in the opposite direction.