title: A method for single-session cocaine self-administration in the mouse.
abstract: BACKGROUND
  Drug self-administration is a powerful method to measure the reinforcing effects of a drug, as well as to investigate behavioral, biochemical, and physiological effects of a drug specific to contingent delivery. With the spectrum of genetically modified mice available, there is a need for well-designed drug self-administration studies tailored for rapid completion of studies in mice.
  
  
  OBJECTIVE
  We set out to develop a methodology in mice for obtaining high levels of cocaine self-administration during the first exposure to the drug.
  
  
  METHODS
  C57Bl/6J mice were trained to lever press for liquid reinforcer on a fixed ratio 1, then a progressive ratio (PR) schedule of reinforcement before intravenous self-administration of cocaine on a PR schedule.
  
  
  RESULTS
  Within a single 16-h session, each mouse self-administered either saline or 0.1, 0.3, 0.6, or 1.2 mg kg(-1) infusion(-1) of cocaine during four distinct 4-h subsessions. Mice showed a strong preference for cocaine vs saline, as demonstrated by higher breakpoints and greater preference for the active lever. Likewise, there was a dose-dependent increase in breakpoints obtained and in drug intake. Finally, animals receiving noncontingent cocaine pressed significantly less than mice self-administering the same dose of cocaine, indicating that a significant amount of active lever pressing is driven by drug-seeking and not the psychomotor-activating effects of cocaine alone.
  
  
  CONCLUSIONS
  Mice will reach high breakpoints and cocaine intake during an initial exposure to cocaine. This method is well-suited to rapidly obtain progressive ratio cocaine self-administration in mice.
authors.affiliation: Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN 37232-0615, USA. chris.olsen@vanderbilt.edu
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Olsen
authors.forename: Danny G
authors.initials: DG
authors.lastname: Winder
mesh_terms: D000818:Animals; D003042:Cocaine / Q000008:administration & dosage*; D003216:Conditioning, Operant / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005106:Exploratory Behavior / Q000187:drug effects; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009043:Motor Activity / Q000187:drug effects; D012055:Reinforcement Schedule; D012646:Self Administration
chemical_list: D003042:Cocaine