Document Detail

Reinforcer-dependent enhancement of operant responding in opioid-withdrawn rats.
MedLine Citation:
PMID:  20686752     Owner:  NLM     Status:  MEDLINE    
RATIONALE AND OBJECTIVE: Opioid withdrawal increases the reinforcing effectiveness of the μ-opioid agonist remifentanil in rodents. The current study explored the selectivity of this effect by assessing operant behavior maintained by drug and non-drug reinforcers, remifentanil, cocaine, a palatable liquid food, and standard food pellets, as a function of opioid dependence and withdrawal.
MATERIALS AND METHODS: Operant responding exhibited by nondependent, morphine-naïve groups was compared with responding exhibited by morphine-dependent and withdrawn groups. Dependence was established using a noncontingent morphine dosing procedure that has been previously verified to maintain dependence while allowing for daily behavioral observation during a withdrawn state. Behavior maintained by remifentanil (0.10-10.0 μg/kg/infusion), cocaine (0.032-1.0 mg/kg/infusion), a palatable liquid food reinforcer (3.2-100.0% Vanilla Ensure® and water), or food pellets was assessed in dependent and nondependent groups.
RESULTS: Morphine withdrawal enhanced remifentanil self-administration, resulting in an upward and rightward shift of the descending limb of the dose-response curve, and increased operant responding for both food reinforcers. However, opioid withdrawal did not affect cocaine self-administration, nor did it affect responding for water.
CONCLUSIONS: Enhanced operant responding observed under opioid-dependent and withdrawn conditions, while selective, is generalized to some nonopioid reinforcers.
Ziva D Cooper; Yong-Gong Shi; James H Woods
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2010-08-05
Journal Detail:
Title:  Psychopharmacology     Volume:  212     ISSN:  1432-2072     ISO Abbreviation:  Psychopharmacology (Berl.)     Publication Date:  2010 Oct 
Date Detail:
Created Date:  2010-10-12     Completed Date:  2011-01-19     Revised Date:  2013-05-29    
Medline Journal Info:
Nlm Unique ID:  7608025     Medline TA:  Psychopharmacology (Berl)     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  369-78     Citation Subset:  IM    
Department of Psychiatry, College of Physicians and Surgeons, Columbia University, New York State Psychiatric Institute, Substance Use Research Center, 1051 Riverside Dr, New York, NY 10032, USA.
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MeSH Terms
Analgesics, Opioid / administration & dosage
Behavior, Animal / drug effects
Cocaine / administration & dosage*
Conditioning, Operant / drug effects*
Dose-Response Relationship, Drug
Morphine / administration & dosage*
Piperidines / administration & dosage
Rats, Sprague-Dawley
Receptors, Opioid, mu / agonists
Reinforcement Schedule
Self Administration
Substance Withdrawal Syndrome / psychology*
Grant Support
DA00254/DA/NIDA NIH HHS; K01 DA027755-02/DA/NIDA NIH HHS; P01 DA000254-35/DA/NIDA NIH HHS
Reg. No./Substance:
0/Analgesics, Opioid; 0/Piperidines; 0/Receptors, Opioid, mu; 50-36-2/Cocaine; 57-27-2/Morphine; P10582JYYK/remifentanil

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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