CENTRAL BEHAVIORAL INTERACTIONS BETWEEN ETHANOL, (-)-NICOTINE, AND (-)-COTININE IN MICE

A high correlation between alcohol use and smoking has long been sugge sted by epidemiological data. We examined the potential behavioral int eractions between ethanol and nicotine using ethanol-induced motor inc oordination as the test response in mice. Effect of pretreatment of va rious doses of (-)-nicotine, (-)-cotinine, a major metabolite of nicot ine, and (+)-nicotine administered ICV on ethanol (IP)-induced motor i ncoordination was investigated. (-)-Nicotine (0. 19, 0.38, 0.77 and, 1 .54 nmoles ICV) produced significant attenuation of motor incoordinati on due to ethanol (2 g/kg IP) in a nearly dose-related manner which wa s blocked by ICV hexamethonium and trimethaphan, both purported nicoti nic antagonists. (-)-Cotinine (0.35, 0.70, 1.41 nmole ICV) produced si milar attenuation but was less potent than (-)-nicotine. Attenuation b y (+)-nicotine(0.19,0.38, and 0.77 nmoles ICV) was also significant bu t only at 0.77 nmole dose level. (+)-Nicotine-induced attenuation of m otor incoordination by ethanol was antagonized by nicotinic antagonist s. Data obtained suggest a central behavioral interaction between etha nol and nicotine at least through the participation of cholinergic nic otinic receptors.