Behavioral and metabolic aspects of cimetidine-ethanol interaction

The effect of cimetidine, an H2 histamine receptor blocker, on spontaneous locomotor activity and ethanol-produced narcosis was studied in the male mouse. The separate and combined effects of cimetidine, and histalog (betazol), an H2 histamine receptor agonist, on voluntary intake of diluted ethanol solution by the rat were also determined. The in vitro effect of cimetidine on rat liver alcohol and aldehyde dehydrogenase was assayed. Cimetidine treatment was associated with an initial moderate increase in locomotor activity which was increased significantly as a function of time. The central depressant action of ethanol, as measured by duration of ethanol-mediated narcosis, was decreased by pretreatment with a single dose of cimetidine. The drug did not alter voluntary drinking of ethanol by the rat but antagonized histalog-produced aversion to ethanol selection when administered prior to histalog. Cimetidine, 3 x 10(-3) M concentration, inhibited rat liver aldehyde dehydrogenase but not alcohol dehydrogenase in vitro. The results indicate cimetidine-ethanol interaction and suggest the implication of histamine in some of the ethanol-elicited responses studied.