An inhalation procedure to produce tolerance to the behavioral effects of ethanol

In male Sprague-Dawley rats the acute effect of ethanol administration (1.0, 2.0, or 3.0 g/kg, IP) on motor coordination was measured by the aerial righting reflex. Ethanol in doses of 2.0 and 3.0 g/kg produced significant impairment of motor coordination with corresponding elevated blood ethanol levels. The rate of ethanol dissappearance from the blood was 0.32 +/- 0.03 mg/ml/hr. Functional tolerance to the effect of ethanol on motor coordination and hypnosis (sleep time) was produced in rats by a 24 hr period of exposure to ethanol vapor (28 mg/liter of air) in a chamber. Animals tested 48 hr after the ethanol inhalation period showed less motor impairment from acute ethanol (3.0 g/kg, IP) and other animals exhibited a reduced sleep time from ethanol (4.0 g/kg, IP) when they were compared with controls. The rate of ethanol elimination from the blood was unchanged in ethanol vapor treated animals (0.30 +/- 0.01 mg/ml/hr) and air-treated animals (0.33 +/- 0.02 mg/ml/hr).