The influence of GABOB and metrazol convulsion upon Na and K content in cerebral cortex of rabbits was studied, and then the influence of GABOB upon metrazol convulsion was investigated. Results were as follows: 1) The intravenous injection of 100 mg GABOB causes decrease of Na content in cerebral cortex of rabbits. The intravenous injection of 10 mg GABOB effects stronger than that of 100 mg in spite of its small dosis. 2) Na content in cerebral cortex of rabbits is increased by metrazol convulsion markedly in its first stadium and decreases from the medium of convulsion. But it does not recover completely even after 30 minutes from the end of the convulsion. 3) If 100 mg GABOB is given intravenously before metrazol convulsion, GABOB restraines the Na content, which had increased temporary by convulsion but which decreases with lapse of time. This level still continues 30 minutes after the end of convulsion. 4) The intravenous injection of 100 mg GABOB decreases markedly the K content in cerebral cortex of rabbits. In case of 10 mg intravenous injection the decrease is also found but it is weaker than that in the case of 100 mg. 5) K content in cerbral cortex of rabbits decreases markedly by metrazol convulsion and it does not recover completely still after 30 minutes from the end of convulsion. 6) The influnence of intravenous injection of 100 mg GABOB upon K content in cerebral cortex of rabbits during metrazol convulsion is seen neither in the first stadium nor the maximum stadium of convulsion but it accelerates the recover after the end of convulsion and let it recover to the normal level 30 minutes after the end of convulsion.