ABSTRACT
Alcoholics generally display cycles of excessive ethanol intake, abstinence and relapse behavior. Using an animal model of relapse-like drinking, the alcohol deprivation effect (ADE), our laboratory has shown that repeated 2-week cycles of ethanol deprivation and re-exposure, following an initial 6-week access period, result in a robust ADE by alcohol-preferring (P) and high alcohol-drinking (HAD-1 and HAD-2) rats. These rat lines have been selectively bred to prefer a 10% ethanol solution over water. The present study examined whether P and HAD rats would display an ADE using much shorter ethanol deprivation and re-exposure intervals. Rats were given either continuous or periodic concurrent access to multiple concentrations (10%, 20%, and 30% [vol/vol]) of ethanol. The periodic protocol involved access to ethanol for 12 days followed by four cycles of 4 days of deprivation and 4 days of re-exposure to ethanol access. High-alcohol-drinking rats displayed a robust 24-h ADE upon first re-exposure (HAD-1: approximately 5 vs. 8g/kg/day; HAD-2: approximately 6 vs. 9g/kg/day, baseline vs. re-exposure), whereas P rats ( approximately 7 vs. 8g/kg/day) displayed a modest, nonsignificant, increase in 24-h intake. In a separate group of rats, ethanol intake and blood alcohol concentrations after the first hour of the fourth re-exposure cycle were HAD-1: 2.0g/kg and 97 mg%, HAD-2: 2.3g/kg and 73 mg%, and P: 1.2g/kg and 71 mg%; with all three lines displaying a robust first hour ADE. These findings suggest that (a) an ADE may be observed with short ethanol deprivation and re-exposure intervals in HAD rats, and (b) the genetic make-up of the P and HAD rats influences the expression of this ADE.
Subject(s)
Alcohol Drinking/psychology , Alcoholism/psychology , Behavior, Addictive , Behavior, Animal/drug effects , Ethanol/administration & dosage , Alcohol Drinking/genetics , Alcoholism/genetics , Animals , Behavior, Addictive/genetics , Body Weight/drug effects , Drinking/drug effects , Drug Administration Schedule , Ethanol/blood , Female , Male , Rats , Rats, Inbred Strains , Recurrence , Self AdministrationABSTRACT
Alcohol abuse among adolescents continues to be a major health problem for our society. Our laboratory has used the peri-adolescent alcohol-preferring, P, rat as an animal model of adolescent alcohol abuse. Even though peri-adolescent P rats consume more alcohol (g/kg/day) than their adult counterparts, it is uncertain whether their drinking is sufficiently aggregated to result in measurable blood ethanol concentrations (BECs). The objectives of this study were to examine daily alcohol drinking patterns of adolescent and adult, male and female P rats, and to determine whether alcohol drinking episodes were sufficiently aggregated to result in meaningful BECs. Male and female P rats were given 30 days of 24 h free-choice access to alcohol (15%, v/v) and water, with ad lib access to food, starting at the beginning of adolescence (PND 30) or adulthood (PND 90). Water and alcohol drinking patterns were monitored 22 h/day with a "lickometer" set-up. The results indicated that (a) peri-adolescent P rats consumed more water and total fluids than adult P rats, (b) female P rats consumed more water and total fluids than male P rats, (c) there were differences in alcohol, and water, licking patterns between peri-adolescent and adult and female and male P rats, (d) individual licking patterns revealed that alcohol was consumed in bouts often exceeding the amount required to self-administer 1 g/kg of alcohol, and (e) BECs at the end of the dark cycle, on the 30th day of alcohol access, averaged 50 mg%, with alcohol intakes during the last 1 to 2 h averaging 1.2 g/kg. Overall, these findings indicate that alcohol drinking patterns differ across the age and sex of P rats. This suggests that the effectiveness of treatments for reducing excessive alcohol intake may vary depending upon the age and/or sex of the subjects being tested.
