Behavioral effects in the mouse during and following withdrawal from ethanol ingestion and/or nicotine administration

The mechanism(s) by which ethanol or nicotine produces dependency and withdrawal symptoms during abstinence is poorly understood. In addition, it has been observed that a high correlation exists between ethanol intake and smoking. Therefore, studies were undertaken to evaluate aversion to the open arms of the elevated plus-maze and the modification of spontaneous locomotor activity during and following repeated ethanol and/or nicotine administration in mice. The ethanol plus nicotine treated animals increased time spent in the open arms of the maze during treatment relative to controls. Withdrawal from this combination treatment led to a rapid onset of intense aversion to the open arms of the maze and a concomitant reduction in locomotor activity which was greater than that produced by withdrawal from ethanol or nicotine treatment alone. The present results suggest that the combined effects of ethanol and nicotine reduced aversion to the open arms of the elevated plus-maze test system and may indicate an anti-aversive action. However, mice demonstrate an increased aversiveness to the open arms following sudden withdrawal of the combination treatment.