MEASUREMENT OF CEREBROSPINAL-FLUID PRESSURE IN CONSCIOUS RATS

We describe a method of using a micro-tip transducer to measure cerebr ospinal fluid pressure (CSFp) through a lateral ventricular cannula in unanesthetized, restrained, non-stressed rats. The mean value of CSFp under the anesthesia was 4.2+/-0.9 (mean+/-SEM, n=6), ranging from 1. 3 to 7.5 mmHg. Measurements were made daily in conscious state for 7 c onsecutive days after the operation. Mean value of CSFp was 9.1+/-0.5 mmHg (n = 42), ranging between 8.0+/-1.4 and 10.4+/-1.3 mmHg (n = 6) f rom day to day (P > 0.05). The permanent intraventricular cannula did not cause any detectable changes in behavior, arterial pressure, arter ial blood gas, arterial blood acid-base chemistry, and water content o f the punctured hemisphere. The results indicated that the method is a reliable alternative for CSFp measurement in a conscious, restrained, non-stressed rat which can be used under a variety of experimental co nditions.