Differential biphasic effects of ethanol have been demonstrated for ethanol-induced motor activity. Ethanol-induced locomotor activity has been shown to be increased among adolescent male and female alcohol-preferring P rats (Rodd et al., 2004). Specifically, in response to an acute dose of 0.50 or 0.75 g/kg ethanol, adolescent P female rats demonstrated increased activity counts relative to animals administered saline or 0.25 g/kg ethanol. Additionally, adolescent P males exhibited elevated activity counts when administered 0.25, 0.50, or 0.75 g/kg ethanol relative to saline controls. In animals of both sexes activity counts were significantly decreased at 1.50 g/kg ethanol. Because of the heightened sensitivity to ethanol among adolescent P females, the present study used out-bred female rats to assess the effects of chronic ethanol administration (PND 34–46) during adolescence to assess the dose-dependent effects of ethanol on locomotor activity to 0.75 and 1.50 g/kg/ip/b.i.d. ethanol (Maldonado and Kirstein, unpublished data). Rats underwent abstinence from PND 47 to PND 59. Rats were then challenged with ethanol (0.75 or 1.50 g/kg/ip) or saline on PND 60.
