Determination of cerebrospinal fluid production rate using a push-pull perfusion procedure in the conscious rat

The inulin dilution technique was used to determine the cerebrospinal fluid (CSF) production rate by means of a push-pull cannula implanted into a lateral ventricle. Artificial CSF containing trace amount of 3H-inulin was perfused for 2 h in conscious rats. 3H-inulin in the effluent reached a plateau level depending on the CSF production rate. The control lateroventricular CSF production was 0.98 microliters/min. Production was reduced to 0.34 microliters/min during a perfusion with acetazolamide (1 mM), a carbonic anhydrase inhibitor.