title: Measuring the incentive value of escalating doses of heroin in heroin-dependent Fischer rats during acute spontaneous withdrawal.
abstract: OBJECTIVE
  Although continued heroin use and relapse are thought to be motivated, in part, by the positive incentive-motivational value attributed to heroin, little is understood about heroin's incentive value during the relapse-prone state of withdrawal. This study uses place preference to measure the incentive value attributed to escalating-dose heroin in the context of heroin dependence.
  
  
  METHODS
  Male Fischer rats were exposed chronically to escalating doses of heroin in the homecage and during place preference conditioning sessions. Conditioned preference for the context paired with escalating-dose heroin was tested after homecage exposure was discontinued and rats entered acute spontaneous withdrawal. Individuals' behavioral and locomotor responses to heroin and somatic withdrawal signs were recorded.
  
  
  RESULTS
  Conditioned preference for the heroin-paired context was strong in rats that received chronic homecage exposure to escalating-dose heroin and were tested in acute withdrawal. Behavioral responses to heroin (e.g., stereotypy) varied widely across individuals, with rats that expressed stronger heroin preference also expressing stronger behavioral activation in response to heroin. Individual differences in preference were also related to locomotor responses to heroin but not to overt somatic withdrawal signs.
  
  
  CONCLUSIONS
  Escalating doses of heroin evoked place preference in rats, suggesting that positive incentive-motivational value is attributed to this clinically relevant pattern of drug exposure. This study offers an improved preclinical model for studying dependence and withdrawal and provides insight into individual vulnerabilities to addiction-like behavior.
authors: Laboratory of the Biology of Addictive Diseases, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA. kseip@rockefeller.edu
authors: Katharine M
authors: KM
authors: Seip
authors: Brian
authors: B
authors: Reed
authors: Ann
authors: A
authors: Ho
authors: Mary Jeanne
authors: MJ
authors: Kreek
mesh_terms: D000818:Animals; D016739:Behavior, Addictive / Q000235:genetics / Q000523:psychology; D003213:Conditioning, Psychological / Q000187:drug effects / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D003932:Heroin / Q000008:administration & dosage*; D006556:Heroin Dependence / Q000235:genetics* / Q000523:psychology; D008297:Male; D009042:Motivation / Q000187:drug effects / Q000235:genetics*; D051381:Rats; D011916:Rats, Inbred F344; D013375:Substance Withdrawal Syndrome / Q000235:genetics* / Q000523:psychology
chemical_list: D003932:Heroin