Antagonism of the hypnotic effect of ethanol in mice by an alpha-1 adrenoceptor agonist.

A lipid soluble alpha 1-adrenoceptor agonist 2-(2-chloro-5-trifluoromethylphenylimino) imidazolidine (St 587) antagonized the hypnotic effect of ethanol in C57Bl/6 and CD-1 mice. In Swiss-Webster mice the effect of St 587 was weak and in BALB/c mice this drug potentiated ethanol hypnosis. St 587 did not enhance the elimination of ethanol. Cirazoline, an alpha 1-adrenoceptor agonist which is more potent than St 587, was relatively more effective in antagonizing the ethanol-induced hypnosis. Though it appears that St 587 exerted its ethanol antagonism by virtue of its alpha 1-adrenoceptor agonistic effect, other contributing factors may also have to be considered. St 587 may prove to be of value in understanding the mechanism of action of ethanol and in the treatment of acute ethanol intoxication.