Ethanol stimulation after chronic exposure in C57 mice.

The effects of chronic exposure to ethanol via an ethanol containing diet on locomotor activity and on the response to depressive and stimulatory doses of ethanol were examined in C57BL/6cr (C57) mice. Mice maintained for approximately 3 weeks on a liquid diet in which 25% of the calories derived from ethanol had blood levels ranging from undetectable to 60 mg% when sampled at 2200 hr. They were less active than nutritionally equivalent controls, were less depressed by a high dose of ethanol (3 g/kg), and were more stimulated by a low dose of ethanol (2 g/kg). The results establish that chronic EtOH exposure via liquid diets attenuate its depressive effect and exacerbate its stimulatory effect on locomotor activity of C57 mice as previously shown for other strains or for rats. The increased activity elevation in chronically exposed mice may reflect an unmasking of excitation upon developing tolerance to EtOH depression.