24-Hour rhythm in susceptibility of C mice to a toxic dose of ethanol

Abstract

Male C mice were injected (i.p.) with 0.8 cc of saline or with a 25% ethanol solution in two experiments. In each experiment, separate subgroups of comparable mice were injected at 4-hour intervals during a 24-hour period, under conditions standardized for periodicity analysis. Death rates from ethanol showed a 24-hour rhythm in susceptibility; over 50% of the mice injected in one phase of rhythm died from the injection of a dose of ethanol which barely killed 30% of comparable mice injected in another phase, 12 hours earlier or 12 hours later. In one experiment, ethanol-induced hypothermia was recorded and its degree also was found to be a function of 24-hour rhythm. Submitted on January 6, 1959