Demonstration of a threshold concentration for ethanol at the time of regaining the righting response in long-sleep and short-sleep mice.

The duration of loss of the righting response (sleep time) is often used to assess central nervous system sensitivity to ethanol. It has been assumed that there is a threshold concentration of ethanol at which an animal will regain the righting response, and that this level should not change with dose or route of administration of ethanol. Five hypnotic doses of ethanol were given to Long-sleep and Short-sleep mice by intraperitoneal injection. At the time of awakening, blood and brain ethanol levels were measured. It was found that within a line, the animals awoke at the same blood and brain ethanol concentration irrespective of the ethanol dose given. The threshold blood ethanol level was 265 mg% for Long-Sleep males and 484 mg% for Short-Sleep males. These results indicate that there is a threshold value for ethanol, and that this threshold is characteristic for a given mouse line.