Ethanol self-administration by alcohol-nonpreferring (NP) rats in a continuous access situation

Male rats, from the alcohol nonpreferring (NP) line, were studied in operant chambers in which food pellets, water, and 10% ethanol (v/v) were available continuously for 23 h/d. The NP rats consumed less ethanol per day following 7 weeks under these conditions than did either alcohol-preferring (P) rats or Long-Evans (LE) studied previously under the same conditions for 4 weeks. The NP rats consumed 0.2 g/kg per day during the first week of the experiment, 0.72 g/kg per day during the fourth week, and 1.03 g/kg per day during the seventh week compared to 2.2 g/kg per day for LE rats and 4.8 g/kg per day for P rats following 4 weeks. These data indicate that NP rats will slowly initiate ethanol self-administration under continuous access conditions, but to a lesser extent and at a slower rate than other lines of rats studied previously.