title: Dependence induced increases in intragastric alcohol consumption in mice.
abstract: Three experiments used the intragastric alcohol consumption (IGAC) procedure to examine the effects of variations in passive ethanol exposure on withdrawal and voluntary ethanol intake in two inbred mouse strains, C57BL/6J (B6) and DBA/2J (D2). Experimental treatments were selected to induce quantitative differences in ethanol dependence and withdrawal severity by: (1) varying the periodicity of passive ethanol exposure (three, six or nine infusions/day); (2) varying the dose per infusion (low, medium or high); and (3) varying the duration of passive exposure (3, 5 or 10 days). All experiments included control groups passively exposed to water. B6 mice generally self-infused more ethanol than D2 mice, but passive ethanol exposure increased IGAC in both strains, with D2 mice showing larger relative increases during the first few days of ethanol access. Bout data supported the characterization of B6 mice as sippers and D2 mice as gulpers. Three larger infusions per day produced a stronger effect on IGAC than six or nine smaller infusions, especially in D2 mice. Increased IGAC was strongly predicted by cumulative ethanol dose and intoxication during passive exposure in both strains. Withdrawal during the passive exposure phase was also a strong predictor of increased IGAC in D2 mice. However, B6 mice showed little withdrawal, precluding analysis of its potential role. Overall, these data support the hypothesis that dependence-induced increases in IGAC are jointly determined by two processes that might vary across genotypes: (1) tolerance to aversive postabsorptive ethanol effects and (2) negative reinforcement (i.e. alleviation of withdrawal by self-administered ethanol).
authors.affiliation: Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, 97201-3098, USA.
authors.forename: Tara L
authors.initials: TL
authors.lastname: Fidler
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Powers
authors.forename: Jason J
authors.initials: JJ
authors.lastname: Ramirez
authors.forename: Andrew
authors.initials: A
authors.lastname: Crane
authors.forename: Jennifer
authors.initials: J
authors.lastname: Mulgrew
authors.forename: Phoebe
authors.initials: P
authors.lastname: Smitasin
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Cunningham
mesh_terms: D000437:Alcoholism / Q000503:physiopathology*; D000818:Animals; D002492:Central Nervous System Depressants / Q000008:administration & dosage*; D004305:Dose-Response Relationship, Drug; D004333:Drug Administration Routes; D004361:Drug Tolerance; D000431:Ethanol / Q000008:administration & dosage*; D007441:Intubation, Gastrointestinal; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D023421:Models, Animal; D012054:Reinforcement, Psychology; D012646:Self Administration / Q000706:statistics & numerical data; D012720:Severity of Illness Index; D013375:Substance Withdrawal Syndrome / Q000503:physiopathology*; D013997:Time Factors; D014867:Water / Q000008:administration & dosage
chemical_list: D002492:Central Nervous System Depressants; D014867:Water; D000431:Ethanol