The alcohol-preferring (P) and –non-preferring (NP) rats were selectively bred for high and low alcohol-drinking behavior, respectively (Lumeng et al., 1977). There are innate neurobiological differences within the nucleus accumbens (ACB) between P and NP rats (reviewed in Bell et al., 2005; McBride and Li, 1998; Murphy et al., 2002). In addition, the P and NP rats differ in a number of behavioral measures (reviewed in McBride and Li, 1998; Murphy et al., 2002). With regard to responses to ethanol, NP rats are more sensitive than P rats to the motor impairing effects of moderate to high dose ethanol (Lumeng et al., 1982; Rodd et al. 2004). In contrast, P rats are sensitive to the low-dose stimulating effects of ethanol, whereas NP rats are not (Waller et al., 1986; Rodd et al., 2004). P rats develop tolerance to the high dose motor impairing effects of ethanol more readily than NP rats (Waller et al., 1983), and tolerance persists longer in the P than NP rat (Gatto et al., 1987). In another study, repeated intraperitoneal (i.p.) injections of 1 g/kg ethanol
