title: Concurrent access to nicotine and sucrose in rats.
abstract: BACKGROUND
  Animal models that allow concurrent access to drug and nondrug reinforcers provide unique insight into the etiology, maintenance, and treatment of drug use.
  
  
  OBJECTIVE
  We sought to develop and utilize a concurrent access procedure with nicotine and sucrose in rats.
  
  
  METHODS
  Pressing one lever delivered intravenous nicotine, and pressing another lever delivered sucrose pellets, with both reinforcers freely available throughout daily sessions.
  
  
  RESULTS
  Rats that had been pretrained with nicotine on some days and sucrose on other days responded on both levers when subsequently given concurrent access, but almost all responded at substantially higher rates on the sucrose lever. In contrast, rats pretrained exclusively with nicotine before being given concurrent access showed individual differences, with about half responding more on the nicotine lever. Treatment with the nicotinic receptor partial agonist varenicline selectively decreased nicotine self-administration. Food restriction and removal of the sucrose lever both increased nicotine self-administration.
  
  
  CONCLUSIONS
  The finding that rats continue to take nicotine when sucrose is concurrently available-and in many cases take it more frequently than sucrose-demonstrates that nicotine self-administration does not only occur in the absence of alternative reinforcement options. As a model of human nicotine use, concurrent access is more naturalistic and has higher face validity than procedures in which only one reinforcer is available or choosing one reinforcer precludes access to other reinforcers. As such, this procedure could be useful for evaluating therapeutic agents and improving our understanding of environmental conditions that promote or discourage nicotine use.
authors.affiliation: Preclinical Pharmacology Section, Behavioral Neuroscience Branch, Intramural Research Program, National Institute on Drug Abuse, Baltimore, MD, 21224, USA, lpanlili@mail.nih.gov.
authors.forename: Leigh V
authors.initials: LV
authors.lastname: Panlilio
authors.forename: Lee
authors.initials: L
authors.lastname: Hogarth
authors.forename: Mohammed
authors.initials: M
authors.lastname: Shoaib
mesh_terms: D000818:Animals; D016739:Behavior, Addictive / Q000139:chemically induced / Q000523:psychology*; D001552:Benzazepines / Q000008:administration & dosage; D003216:Conditioning, Operant / Q000187:drug effects / Q000502:physiology; D008297:Male; D009538:Nicotine / Q000008:administration & dosage*; D011810:Quinoxalines / Q000008:administration & dosage; D051381:Rats; D017207:Rats, Sprague-Dawley; D012054:Reinforcement, Psychology; D012646:Self Administration; D013395:Sucrose / Q000008:administration & dosage*; D000068580:Varenicline
chemical_list: D001552:Benzazepines; D011810:Quinoxalines; D013395:Sucrose; D009538:Nicotine; D000068580:Varenicline