Effects of prior ethanol exposure on ethanol self-administration in a continuous access situation using retractable drinking tubes

To examine whether exposure to ethanol influences subsequent ethanol consum ption using a continuous access procedure, two groups of rats were given di ffering initial exposure to ethanol. One group underwent a sucrose-substitu tion initiation procedure. The second group received abbreviated initiation consisting of one-session exposure to each ethanol/sucrose combination use d in standard initiation. The animals were then provided with 23 h/day acce ss to ethanol (10%, v/v) from a retractable drinking tube. Food pellets wer e available following a single-lever press, and water was available from a sipper tube. After 5 weeks, the data indicated that few significant differe nces existed between the groups on total ethanol (g/kg), food or water cons umed. The overall intake (g/kg/day), number of ethanol bents per day, and a mount consumed per bout (g/kg/bout) were substantially lower than observed in previous research using ethanol presented in a dipper. However, differen ces in g/kg per ethanol bout did differ significantly between the two group s with the group receiving standard initiation showing more ethanol consume d per bout. These data agree with our previous work indicating that initiat ion results in larger drinking bouts. (C) 2000 Elsevier Science Inc. All ri ghts reserved.