Variations in protein permeability in different regions of the cerebrospinal fluid

Abstract

The total protein concentration was measured in three regions of cerebrospinal fluid (CSF) in the cat. Values obtained were: cortical subarachnoid fluid 53.2 mg/100 ml; cisterna magna fluid 18.0 mg/100 ml; and lumbar subarachnoid fluid 36.3 mg/100 ml. The influx of protein into these regions of CSF was measured during steady-state perfusions of artificial CSF. Corrected protein influx was highest in cortical-subarachnoid perfusions (29.4 μg/min); intermediate in ventricular perfusions (7.6 μg/min), and lowest in spinal subarachnoid perfusions (4.8 μg/min). Protein permeability in the spinal subarachnoid space was approximately four times lower than in the intracranial compartments, indicating that the high concentration of protein in the lumbar fluid results from a slower rate of removal of protein from this region. In contrast, the high concentration of protein in the cortical subarachnoid fluid resulted from a high rate of influx of protein, presumably from the adjacent brain extracellular space.