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Strain dependence of adolescent C annabis influence on heroin reward and mesolimbic dopamine transmission in adult L ewis and F ischer 344 rats
Author(s) -
Cadoni Cristina,
Simola Nicola,
Espa Elena,
Fenu Sandro,
Di Chiara Gaetano
Publication year - 2015
Publication title -
addiction biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.445
H-Index - 78
eISSN - 1369-1600
pISSN - 1355-6215
DOI - 10.1111/adb.12085
Subject(s) - heroin , conditioned place preference , psychology , dopamine , extinction (optical mineralogy) , nucleus accumbens , cannabinoid , pharmacology , cannabis , neuroscience , chemistry , medicine , psychiatry , drug , mineralogy , receptor
Adolescent C annabis exposure has been hypothesized to act as a gateway to opiate abuse. In order to investigate the role of genetic background in cannabinoid–opiate interactions, we studied the effect of Δ 9 ‐tetrahydrocannabinol ( THC ) exposure of adolescent L ewis and F ischer 344 rats on the responsiveness of accumbens shell and core dopamine ( DA ), as monitored by microdialysis, to THC and heroin at adulthood. Heroin reward and reinstatement by heroin priming were studied by conditioned place preference ( CPP ) and cognitive and emotional functions by object recognition, Y maze and elevated plus maze paradigms. THC stimulated shell DA in L ewis but not in F ischer 344 rats. Adolescent THC exposure potentiated DA stimulant effects of heroin in the shell and core of L ewis and only in the core of F ischer 344 rats. Control L ewis rats developed stronger CPP to heroin and resistance to extinction compared with F ischer 344 strain. In L ewis rats, THC exposure did not affect heroin CPP but potentiated the effect of heroin priming. In F ischer 344 rats, THC exposure increased heroin CPP and made it resistant to extinction. L ewis rats showed seeking reactions during extinction and hedonic reactions in response to heroin priming. Moreover, adolescent THC exposure affected emotional function only in L ewis rats. These observations suggest that long‐term effects of C annabis exposure on heroin addictive liability and emotionality are dependent on individual genetic background.