RELEASE OF γ‐AMINOBUTYRIC ACID INTO THE FOURTH VENTRICLE INDUCED BY STIMULATION OF THE CAT'S CEREBELLUM

The fourth ventricle of the cat was perfused and the release of γ‐aminobutyric acid (GABA) into the perfusate was measured. GABA was released at a rate of 6·69 × 10−10 moles/min and increased about three times during cerebellar cortical stimulation at 200/sec. It is suggested that GABA is released from axon terminals of Purkinje cells in cerebellar subcortical nuclei.