ALTERNATE PATHWAY FOR CEREBROSPINAL FLUID ABSORPTION IN ANIMALS WITH EXPERIMENTAL OBSTRUCTIVE HYDROCEPHALUS

Transventricular absorption of cerebrospinal fluid (CSF) as an alternate pathway was examined in cats with experimental obstructive hydrocephalus. The isolated ventricular system was perfused under high (>13 cm H2O) or low (≤0 cm H2O) pressure with an artificial spinal fluid containing 131I-CSA (cat serum albumin). The uptake of radioactivity was measured in serial sections of brain tissue from the ventricular to the pial surface. The uptake of 131I-CSA in the brain of the hydrocephalic cats perfused for 4 hours was not related to perfusion pressure. However, the concentration attained after 1 hour of perfusion was higher in the animals perfused under high pressure. In the latter group the uptake after 1 hour was identifical to that found after 4 hours. This suggests that the perfusion pressure is important to increase the rate of flow of 131I-CSA (and fluid) through the extracellular spaces. The distance beyond the ventricular surface to which the perfusate penetrated before it was removed by the blood was 2.5-3 mm. © 1969.