Document Detail

Dissociation of psychomotor sensitization from compulsive cocaine consumption.
MedLine Citation:
PMID:  16034440     Owner:  NLM     Status:  MEDLINE    
The transition from drug use to drug addiction is associated with a process of escalation, whereby drug use becomes excessive and difficult to control. Several mechanisms have been advanced to explain escalating patterns of drug use as opposed to nonescalating patterns. Although current evidence favors hedonic tolerance, there remains some dispute about the contribution of behavioral sensitization to cocaine intake escalation. Here, we concurrently assessed the ability of cocaine to induce psychomotor sensitization and drug-seeking behavior in animals with 1-h (short access or ShA) vs 6-h (long access or LgA) access to intravenous (i.v.) cocaine self-administration. As expected, cocaine intake by LgA rats escalated over time and became excessive compared to cocaine intake by ShA rats, which remained low and stable. Despite escalated levels of cocaine consumption, however, LgA rats were not more sensitized to cocaine than ShA rats. The dose-effect function for cocaine-induced locomotion (0.125-1 mg, i.v.) was shifted to the left in LgA rats by the same amount as in ShA rats after cocaine self-administration. In contrast, LgA rats were much more responsive than ShA rats to the motivational effects of cocaine, as measured by the ability of i.v. cocaine to reinstate extinguished drug-seeking behavior. This study demonstrates a dissociation of psychomotor sensitization from the change in motivation underlying the transition to compulsive cocaine consumption, and therefore suggests that responsiveness to the motivational effects of the drug, not psychomotor sensitization, would represent a specific behavioral marker of the transition to and maintenance of compulsive cocaine use.
Serge H Ahmed; Martine Cador
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology     Volume:  31     ISSN:  0893-133X     ISO Abbreviation:  Neuropsychopharmacology     Publication Date:  2006 Mar 
Date Detail:
Created Date:  2006-02-17     Completed Date:  2006-05-12     Revised Date:  2011-05-18    
Medline Journal Info:
Nlm Unique ID:  8904907     Medline TA:  Neuropsychopharmacology     Country:  United States    
Other Details:
Languages:  eng     Pagination:  563-71     Citation Subset:  IM    
Laboratoire de Neuropsychobiologie des Désadaptations, University Victor-Segalen Bordeaux2, Bordeaux, France.
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MeSH Terms
Central Nervous System Stimulants / pharmacology*
Cocaine / pharmacology*
Cocaine-Related Disorders / psychology*
Conditioning, Operant / drug effects
Dose-Response Relationship, Drug
Motor Activity / drug effects*
Rats, Wistar
Self Administration
Reg. No./Substance:
0/Central Nervous System Stimulants; 50-36-2/Cocaine

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

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