Ethanol enhancement of the motor-stimulating effect of nicotine in the rat.

Although ethanol stimulates locomotion in mice, it has been difficult to demonstrate such an action in rats. In contrast, nicotine has been shown to enhance locomotion, including ipsiversive rotation in nigral-lesioned rats. We found no significant effect of ethanol alone on rat rotation at doses of 0.125, 0.50, 1.0, and 2.0 g/kg, IP, during a 30-min observation period. However, there was a dose-dependent effect of ethanol enhancing the rotation induced by nicotine (0.4 mg/kg, SC) given 30 min after the ethanol. The interaction of ethanol and nicotine on locomotion most likely involves the release of dopamine and may be related to the motor abnormalities sometimes seen clinically.