title: Strain dependence of adolescent Cannabis influence on heroin reward and mesolimbic dopamine transmission in adult Lewis and Fischer 344 rats.
abstract: Adolescent Cannabis 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 Lewis and Fischer 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 Lewis but not in Fischer 344 rats. Adolescent THC exposure potentiated DA stimulant effects of heroin in the shell and core of Lewis and only in the core of Fischer 344 rats. Control Lewis rats developed stronger CPP to heroin and resistance to extinction compared with Fischer 344 strain. In Lewis rats, THC exposure did not affect heroin CPP but potentiated the effect of heroin priming. In Fischer 344 rats, THC exposure increased heroin CPP and made it resistant to extinction. Lewis rats showed seeking reactions during extinction and hedonic reactions in response to heroin priming. Moreover, adolescent THC exposure affected emotional function only in Lewis rats. These observations suggest that long-term effects of Cannabis exposure on heroin addictive liability and emotionality are dependent on individual genetic background.
authors: Institute of Neuroscience, National Research Council of Italy, Italy; National Institute of Neuroscience, University of Cagliari, Italy; Centre of Excellence 'Neurobiology of Dependence', University of Cagliari, Italy.
authors: Cristina
authors: C
authors: Cadoni
authors: Nicola
authors: N
authors: Simola
authors: Elena
authors: E
authors: Espa
authors: Sandro
authors: S
authors: Fenu
authors: Gaetano
authors: G
authors: Di Chiara
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D063386:Cannabinoid Receptor Agonists / Q000494:pharmacology*; D004298:Dopamine / Q000378:metabolism*; D013759:Dronabinol / Q000494:pharmacology*; D003932:Heroin / Q000494:pharmacology*; D006556:Heroin Dependence / Q000235:genetics*; D008297:Male; D017551:Microdialysis; D009294:Narcotics / Q000494:pharmacology*; D009714:Nucleus Accumbens / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D011916:Rats, Inbred F344; D011917:Rats, Inbred Lew; D012201:Reward; D009435:Synaptic Transmission / Q000187:drug effects / Q000235:genetics
chemical_list: D063386:Cannabinoid Receptor Agonists; D009294:Narcotics; D003932:Heroin; D013759:Dronabinol; D004298:Dopamine
keywords: elevated plus maze; heroin; microdialysis; nucleus accumbens core; nucleus accumbens shell; Δ9-tetrahydrocannabinol