It is reported that GABA (γ-amino butyric acid) & GABOB (γ-amino β-hydroxy butyric acid) have an inhibitory action to the central nervous system. Recently, S-GABA (γ-amino β-sulfonyl butyric acid) & P-GABA (γ-amino β-phenyl butyric acid) have been composed from GABOB, and reported that they also have an inhibitory action to the convulsive seizure. In the experiments in dogs, P-GABA, S-GABA & GABOB solutions were applied on the cerebral at rest and after discharge caused by electrical stimulation of motor cortex were recorded to examine the anti-convulsive action of these solutions. In the experiments in cats, cortical evoked potentials caused by electrical stimulation of thalamus were recorded to examine the action of GABOB by mearns of computer technique. Furthermore, the application of GABOB & S-GABA solution on the epileptogenic cortical focus of human epileptic was performed and the corticogram was recorded with reference to spikes and after-discharges to examine the anti-convulsive actions of these solutions. The results are following: 1) Application of S-GABA solution on the cerebral cortex caused low voltage activity and spiking activity in corticogram. 2) P-GABA caused spiking activity, developing to the generalized convulsive seizure pattern. 3) These spiking activity caused by S-GABA and P-GABA was, inhibited by GABOB
solution. 4) S-GABA did not inhibit the after discharge or spiking activity on the epileptogenic cortical focus of human epileptic. GABOB, however, showed a strong inhibitry action to after discharge & spiking activity. 5) Application of GABOB on the cerebral cortex reversed the cortical evoked potentials caused by electrical stimulation of thalamus. From these findings, it is concluded that GABOB has an inhibitory action on the cerebral cortex, but S-GABA & P-GABA have no inhibitory action.