Inactivation Process of Gamma-Aminobutyric Acid Action on the Isolated Ileum

1) The action and inactivation process of GABA were analyzed in the excised ileum of rabbits and guinea pigs. 2) GABA usually produced an increase in the spontaneous activity of the ileum of rabbits, while in guinea pigs the action was in general depressive. 3) GABA action on nicotine-induced responses was gradually inactivated immediately after the application with a half-decay time of approximately 60 to 120 sec. And became completely ineffective within 2 to 7 min. 4) The inactivation process was independent upon the pH of GABA solution and the dose of GABA administered. The author wishes thank prof. H. Yamaguchi, Department of Pharmacology, for his technical guidance.