title: Microstructural analysis of rat ethanol and water drinking patterns using a modified operant self-administration model.
abstract: BACKGROUND
  Ethanol drinking pattern has emerged as an important factor in the development, maintenance, and health consequences of alcohol use disorders in humans. The goal of these studies was to further our understanding of this important factor through refinement of an operant rodent model of ethanol consumption capable of drinking pattern microstructural analysis. We evaluated measures of total consumption, appetitive behavior, and drinking microstructure for ethanol and water at baseline and assessed alterations induced by two treatments previously shown to significantly alter gross ethanol appetitive and consummatory behaviors in opposing directions.
  
  
  METHODS
  Male Long-Evans rats were trained on an FR1 operant paradigm which allowed for continuous liquid access until an 8 second pause in consumption resulted in termination of liquid access. Total appetitive and consummatory behaviors were assessed in addition to microstructural drinking pattern for both ethanol and water during a five day baseline drinking period, after chronic intermittent ethanol vapor exposure, and following administration of a cannabinoid receptor antagonist SR141716a.
  
  
  RESULTS
  As in previous operant studies, ethanol vapor exposure resulted in increases in ethanol-directed responding, total consumption, and rate of intake. Further, striking differential alterations to ethanol and water bout size, duration, and lick pattern occurred consistent with alterations in hedonic evaluation. Vapor additionally specifically reduced the number of ethanol-directed lever presses which did not result in subsequent consumption. SR141716a administration reversed many of these effects.
  
  
  CONCLUSIONS
  The addition of microstructural analysis to operant self-administration by rodents provides a powerful and translational tool for the detection of specific alterations in ethanol drinking pattern which may enable insights into neural mechanisms underlying specific components of drug consumption.
authors.affiliation: Department of Physiology & Pharmacology, Wake Forest School Medicine, Winston-Salem, NC, United States; Neuroscience and Alcohol Research Training Programs, Wake Forest School Medicine, Winston-Salem, NC, United States.
authors.forename: Stacey L
authors.initials: SL
authors.lastname: Robinson
authors.affiliation: Department of Physiology & Pharmacology, Wake Forest School Medicine, Winston-Salem, NC, United States. Electronic address: bmccool@wakehealth.edu.
authors.forename: Brian A
authors.initials: BA
authors.lastname: McCool
mesh_terms: D000428:Alcohol Drinking; D000704:Analysis of Variance; D000818:Animals; D063387:Cannabinoid Receptor Antagonists / Q000494:pharmacology; D003216:Conditioning, Operant / Q000502:physiology*; D004327:Drinking Behavior / Q000502:physiology*; D000431:Ethanol / Q000008:administration & dosage*; D008297:Male; D010880:Piperidines / Q000494:pharmacology; D011720:Pyrazoles / Q000494:pharmacology; D051381:Rats; D020318:Rats, Long-Evans; D012055:Reinforcement Schedule; D000077285:Rimonabant; D012646:Self Administration; D013997:Time Factors; D014867:Water / Q000008:administration & dosage*
chemical_list: D063387:Cannabinoid Receptor Antagonists; D010880:Piperidines; D011720:Pyrazoles; D014867:Water; D000431:Ethanol; D000077285:Rimonabant
keywords: Drinking pattern; Ethanol; Ethanol vapor; Microstructure; Operant self-administration