Heroin-Induced Reinstatement is Specific to Compulsive Heroin Use and Dissociable from Heroin Reward and Sensitization

1. Neuropsychopharmacology. 2007 Mar;32(3):616-24. doi: 10.1038/sj.npp.1301083.
Epub 2006 Apr 26.

Heroin-induced reinstatement is specific to compulsive heroin use and
dissociable from heroin reward and sensitization.

Lenoir M(1), Ahmed SH.

Author information:
(1)Laboratoire de Neuropsychobiologie des Désadaptations, University
Victor-Segalen Bordeaux2, CNRS-UMR 5541, Bordeaux, France.

Increased drug availability can precipitate a rapid transition to compulsive
drug use in both vulnerable humans and laboratory animals. Recent studies have
shown that despite equivalent levels of psychomotor sensitization, only rats
with prolonged, but not limited, access to cocaine self-administration respond
to the priming effects of cocaine on drug seeking, as measured in a
within-session reinstatement model of drug craving. In this model, drug seeking
is first extinguished and then reinstated by non-contingent presentations of the
drug alone in the absence of response-contingent stimuli. Here, we assessed the
generality of this observation in rats with daily short (1 h, ShA) vs long
access (6 h, LgA) to i.v. heroin self-administration. As expected, heroin intake
by LgA rats (n=24) increased over time to become excessive compared to heroin
intake by ShA rats (n=24). After escalation, LgA rats tended to be less
sensitive to heroin-induced locomotion (7.5-30 microg, i.v.) than ShA rats. In
contrast, only LgA rats, not ShA rats, responded to the priming effects of
heroin, as measured by the ability of heroin alone (7.5-30 microg, i.v.) to
reinstate extinguished drug-seeking behavior. Finally, during the course of
heroin intake escalation, a large proportion of LgA rats developed self-injury
(mostly targeting the nails and digit tips of the forepaws), a negative
consequence not seen in ShA rats. This study reproduces and extends previous
research on compulsive cocaine use by showing that heroin-induced reinstatement
is also specific to compulsive drug use and dissociable from heroin-induced
reward and psychomotor sensitization.

DOI: 10.1038/sj.npp.1301083
PMID: 16641938 [Indexed for MEDLINE]

Auteurs Bordeaux Neurocampus