Development of central nervous system sensitivity to ethanol and pentobarbital in short- and long-sleep mice

Dose-response curves to ethanol from day 9 to adulthood have been carried out in short-sleep and long-sleep mice. At very young ages, up to about 35 days of age, the mice differ in sleep time response to ethanol, but this difference is due to the development of acute tolerance. At older ages the differences in sleep times are due to a combination of acute tolerance and differences in initial sensitivity. In contrast to adult mice, that show no difference in brain sensitivity to pentobarbital, short-sleep mouse pups ranging in age from days 9 to 12 are more sensitive to pentobarbital than are long-sleep mice. The difference in sensitivity at young ages is again due to differences in development of acute tolerance and not to initial sensitivity differences. It is postulated that the development of acute tolerance to ethanol is rapid, within minutes, following injection of ethanol and that the system responsible might be the gamma-amino-butyric acid-mediated chloride flux which has also been shown to develop tolerance within 5 min after ethanol injection.