Discriminative Stimulus- vs. Conditioned Reinforcer-Induced Reinstatement of Drug-Seeking Behavior and arc mRNA Expression in Dorsolateral Striatum
Drug seeking in the context of stimuli associated with drug use contributes to recidivism in drug-addicted people. Although numerous brain areas have been implicated in mediating the effects of drug-conditioned cues on drug-seeking behavior, the role of the dorsolateral striatum in such cue-induced reinstatement is less clear. Particularly, the neuronal populations in which plasticity occurs and in which subsequent activity produces the effects of these cues on drug-seeking behavior are not known. Cellular compartment analysis of temporal activity by fluorescence in situ hybridization (catFISH) identifies whether the same neurons are activated by temporally discrete events. We applied this approach to brains from animals trained to both initiate cocaine self-administration in response to a discriminative stimulus and to reinstate/maintain responding to gain access to a conditioned reinforcer to examine whether the same neuronal ensembles are activated in the dorsolateral striatum by these two types of cues. CatFISH experiments did not reveal significant increases in the number of cells with arc mRNA expression in animals reinstating drug seeking relative to control animals exposed to the same stimuli. However, there was a significant correlation between arc mRNA expression and cue-induced operant responding on the test day, suggesting that the dorsolateral striatum in general, and arc expression in particular, may play a role in cue-induced reinstatement of drug-seeking behavior.
KeywordsDiscriminative Stimulus Lever Press Dorsal Striatum Conditioned Reinforcer Reinstatement Test
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