Social reinstatement: a rat model of peer-induced relapse
An important factor that can lead to drug relapse is to re-associate with drug-using social peers, but there is little literature on the effect of social peers on relapse in animal models.
The current study used a dual-compartment operant conditioning apparatus that allowed adult male rats to respond for cocaine in the presence of a conspecific. In experiment 1, rats were trained to self-administer cocaine in the presence of a social peer that was separated by a wire screen partition and then that peer was used as a reinstatement cue following a period of extinction. In the next experiments, rats were trained on alternating sessions to self-administer cocaine in the presence of one peer and to self-administer saline in the presence of a different peer using either a single-active lever procedure (experiment 2) or a double-active lever procedure (experiment 3). Following extinction of responding in the absence of the peers, the effect of re-exposure to the cocaine- and saline-associated peers on reinstatement of drug seeking was determined. This was tested using both single- and double-active lever procedures.
In experiment 1, a peer that was present throughout cocaine self-administration was able to reinstate cocaine seeking following a period of extinction. In experiments 2 and 3, drug seeking was reinstated by the cocaine-associated peer (S+), but not the saline-associated peer (S−). This discrimination occurred when using either the single-active lever procedure or double-active lever procedure.
These results indicate that a social peer can be used as a discriminative stimulus to signal cocaine availability and that re-introduction of a peer previously paired with cocaine can reinstate cocaine seeking, confirming clinical reports that peer affiliation among abstinent cocaine users is an important determinant of relapse.
KeywordsCocaine Self-administration Social Reinstatement
The authors would like to thank Dr. Yavin Shaham for consultation in designing experiment 3.
This work was funded by NIH grants R21 DA041755, P50 DA05312, and T32 DA016176.
Compliance with ethical standards
All procedures were in accordance with the “Guide for the Care and Use of Laboratory Animals” (National Research Council 2010) and were approved by the Institutional Animal Care and Use Committee at the University of Kentucky.
Conflict of interest
The authors declare that they have no conflicts of interest.
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