Ming Chang, Hiroshi Saito and Kazuho Abe (*)
Department of Chemical Pharmacology, Faculty of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113, Japan
(*) To whom correspondence should be addressed.
Abstract: We investigated the effect of cimetidine, a clinically used H2-receptor antagonist, on the induction of long-term potentiation (LTP) in the dentate gyrus of anesthetized rats. Intracerebroventricular injection of cimetidine (50 - 100 nmol) inhibited the induction of LTP in a dose-dependent manner. The inhibitory effect of cimetidine was not mimicked by other H2-receptor antagonists (ranitidine, famotidine) or the H1-receptor antagonist diphenhydramine or the H3-receptor antagonist thioperamide. These results suggest that cimetidine inhibits hippocampal synaptic plasticity by a novel brain mechanism unrelated to H1, H2 or H3 receptors.
Keywords: Cimetidine, Long-term potentiation, Hippocampus