In the current study varenicline (VAR) lowered alcohol intake during alcohol reaccess following each of 3 alcohol deprivation periods. VAR in doses of 1.0 mg/kg and 2.0 mg/kg reduced alcohol intake during all 3 alcohol reaccess periods and a dose of 0.5 mg/kg reduced alcohol intake during the first 2 alcohol reaccess periods. The mechanism underlying VARs ability to reduce alcohol intake is not clear. It is well known that alcohol increases the release of dopamine (DA) in the nucleus accumbens (NAc) during the first hour following peripheral or central alcohol administration (Di Chiara and Imperato, 1988; Ericson et al., 2009) or following alcohol consumption (Weiss et al., 1993). This increased DA release is thought to mediate the reinforcing (euphoric) effects of alcohol that contribute to alcohol drinking (Di Chiara and Imperato, 1988; Koob, 1992; Samson et al., 1992; Weiss et al., 1993). VAR also releases DA in the NAc during the first hour following central administration, though to a lesser degree than does alcohol, and continues to stimulate DA release for several hours following administration (Ericson et al., 2009).
