| Abstract No.: | A-G1194 |
| Country: | Canada |
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| Title: | ENHANCING EFFECT OF HEROIN ON SOCIAL MEMORY: MODULATION BY PREVIOUS HEROIN EXPOSURE
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| Authors/Affiliations: | 1 AnneMarie Levy*; 1 Elena Choleris; 1 Francesco Leri;
1 University of Guelph, ON, Canada.
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| Content: | Objectives: In rodent models of relapse based on reconditioning of self-administration (SA) and conditioned place preference (CPP), reacquisition of heroin conditioned responses is usually quite rapid. This may be because heroin exposure enhances heroin reinforcing properties and therefore makes it more effective in promoting reacquisition of heroin-conditioned responses. This study was designed to assess whether heroin pre-exposure via SA and CPP could alter its reinforcing efficacy as indexed by its ability to promote non-drug related learning. Materials and Methods: Thus, using a social recognition learning task which assesses changes in rates of investigation of con-specific animals during habituation (4 sessions) and dishabituation (1 session), male Sprague-Dawley rats received 0,0.3 or 1 mg/kg heroin immediately following each habituation session. An additional group was injected with 1 mg/kg heroin 2 hours following habituation sessions to verify whether the effect of heroin was time-dependent. Two other groups received post-habituation 1 mg/kg heroin as above, but these animals were previously (7 days withdrawal) exposed to heroin during CPP (1 mg/kg SC, 1 injection/day x 4 days) or SA (0.05 mg/kg/infusion IV, 3 h/day x 9 days) conditioning.
Results: It was found that heroin enhanced rate of habituation and magnitude of dishabituation in a dose- and time-dependent manner, indicating an improvement of social recognition learning. However, previous exposure to heroin via CPP or SA had no effect. Conclusion: Taken together, these results suggest that rapid reacquisition of heroin conditioned responses by heroin reconditioning may not be fully accounted for by an effect of heroin pre-exposure on its ability to promote learning in general.
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