title: Effects of long-term episodic access to ethanol on the expression of an alcohol deprivation effect in low alcohol-consuming rats.
abstract: BACKGROUND
  The alcohol-preferring (P) and -nonpreferring (NP) and high alcohol-drinking (HAD) and low alcohol-drinking (LAD) rats have been selectively bred for divergent preference for ethanol over water. In addition, both P and HAD rats display an alcohol deprivation effect (ADE). This study was undertaken to test whether the NP, LAD-1, and LAD-2 lines of rats could display an ADE as well.
  
  
  METHODS
  Adult female NP, LAD-1, and LAD-2 rats were given concurrent access to multiple concentrations of ethanol [5, 10, 15% (v/v)] and water in an ADE paradigm involving an initial 6 weeks of 24-hr access to ethanol, followed by four cycles of 2 weeks of deprivation from and 2 weeks of re-exposure to ethanol (5, 10, and 15%). A control group had continuous access to the ethanol concentrations (5, 10, and 15%) and water through the end of the fourth re-exposure period.
  
  
  RESULTS
  For NP rats, a preference for the highest ethanol concentration (15%) was evident by the end of the fifth week of access (approximately 60% of total ethanol fluid intake). Contrarily, LAD rats did not display a marked preference for any one concentration of ethanol. All three lines displayed an ADE after repeated cycles of re-exposure to ethanol, with the general ranking of intake being LAD-1 > NP > LAD-2 (e.g., for the first day of reinstatement of the third re-exposure cycle, intakes were 6.5, 2.9, and 2.4 g/kg/day compared with baseline values of 3.1, 2.0, and 1.3 g/kg/day for each line, respectively). By the 13th week, rats from all three lines, with a ranking of LAD-1 > NP > LAD-2, were drinking more ethanol (3.3, 2.2, and 2.0 g/kg/day, respectively) compared with their consumption during the first week of access (approximately 1.1 g/kg/day for all three lines).
  
  
  CONCLUSIONS
  These data indicate that access to multiple concentrations of ethanol and exposure to multiple deprivation cycles can partially overcome a genetic predisposition of NP, LAD-1, and LAD-2 rats for low alcohol consumption. In addition, the findings suggest that genetic control of low alcohol consumption in rats is not associated with the inability to display an ADE.
authors.affiliation: Indiana University School of Medicine, Department of Psychiatry, Institute of Psychiatric Research, 791 Union Drive, Indianapolis, IN 46202-4887, USA. ribell@iupui.edu
authors.forename: Richard L
authors.initials: RL
authors.lastname: Bell
authors.forename: Zachary A
authors.initials: ZA
authors.lastname: Rodd
authors.forename: Caron L
authors.initials: CL
authors.lastname: Boutwell
authors.forename: Cathleen C
authors.initials: CC
authors.lastname: Hsu
authors.forename: Lawrence
authors.initials: L
authors.lastname: Lumeng
authors.forename: James M
authors.initials: JM
authors.lastname: Murphy
authors.forename: Ting-Kai
authors.initials: TK
authors.lastname: Li
authors.forename: William J
authors.initials: WJ
authors.lastname: McBride
mesh_terms: D000428:Alcohol Drinking / Q000235:genetics*; D000818:Animals; D004305:Dose-Response Relationship, Drug; D000431:Ethanol / Q000008:administration & dosage*; D005260:Female; D051381:Rats; D013045:Species Specificity; D013995:Time; D013997:Time Factors
chemical_list: D000431:Ethanol