Studies on the Formation and Absorption of Cerebrospinal Fluid in Experimental Cerebral Edema and the Effect of Hypertonic Urea on the Cerebrospinal Fluid Circulation

The rate of bulk formation and bulk absorption of cerebrospinal fluid (CSF) was measured by means of ventriculo-cisternal per fusion with artificial CSF associated with inulin dilution technique in rabbits. The formation rate was calculated from outflow-inflow volume difference and inulin clearance, while the absorption rate was estimated by the latter. Experiments were carried out in normal animals and those with cerebral edema. The effect of intravenous hypertonic urea was examined in each experimental group. Cerebral edema was produced by extradural balloon method and intracarotid injection of sesame oil. The rate of formation and absorption of CSF in the normal rabbits were estimated as 18.0 ± 2.8 and 13.2 ± 2.7 μl/min. respectively. Formation rate of CSF was decreased to 82 % of control in the extradural balloon group while no significant change in the oil injection group. On the contrally, considerable decrease in the absorption rate was observed on cerebral edema of both groups