Chronic psychosocial stress causes delayed extinction and exacerbates reinstatement of ethanol-induced conditioned place preference in mice

Abstract

Rationale We have shown previously, using an animal model of voluntary ethanol intake and ethanol-conditioned place preference (EtOH-CPP), that exposure to chronic psychosocial stress induces increased ethanol intake and EtOH-CPP acquisition in mice. Objective Here, we examined the impact of chronic subordinate colony (CSC) exposure on EtOH-CPP extinction, as well as ethanol-induced reinstatement of CPP. Methods Mice were conditioned with saline or 1.5 g/kg ethanol and were tested in the EtOH-CPP model. In the first experiment, the mice were subjected to 19 days of chronic stress, and EtOH-CPP extinction was assessed during seven daily trials without ethanol injection. In the second experiment and after the EtOH-CPP test, the mice were subjected to 7 days of extinction trials before the 19 days of chronic stress. Druginduced EtOH-CPP reinstatement was induced by a priming injection of 0.5 g/kg ethanol. Results Compared to the single-housed colony mice, CSC mice exhibited increased anxiety-like behavior in the elevated plus maze (EPM) and the open field tests. Interestingly, the CSC mice showed delayed EtOH-CPP extinction. More importantly, CSC mice showed increased alcohol-induced reinstatement of the EtOH-CPP behavior. Conclusion Taken together, this study indicates that chronic psychosocial stress can have long-term effects on EtOH-CPP extinction as well as drug-induced reinstatement behavior and may provide a suitable model to study the latent effects of chronic psychosocial stress on extinction and relapse to drug abuse.

M5 Muscarinic Receptor Gene Deletion Accelerates Extinction, But Inhibits Reinstatement of Morphine-Conditioned Reward in Mice

“…No significant difference was found between the wild-type and M5 KO mice. These results indicate amphetamine-specific induction of anxiety-like behavior in the priming test in both genotypes of mice [42,43].…”

Nucleus accumbens lentiviral-mediated gain of function of the oxytocin receptor regulates anxiety- and ethanol-related behaviors in adult mice

“…As classical parameters related to anxiety behavior, the following parameters were hand-scored by the experimenter: i) the number of entries into the OA, ii) the time spent in the OA, and iii) the number of entries into the CA (overall activity). The maze was cleaned with 70% ethanol solution between tests [34,[40][41][42].…”

Environmental enrichment blocks reinstatement of ethanol-induced conditioned place preference in mice

“…After extinction, 0.8 g/kg of ethanol would reinstate the CPP induced by 1.6 g/kg. Reinstatement of CPP has also been demonstrated in C57Bl/6J mice [3], and they found that 0.5 g/kg of ethanol would markedly reinstate the CPP induced by 1.5 g/kg. But they used a unbiased CPP procedure with two chambers device and the training and testing time were different from us.…”

“…The place conditioning procedure was similar to that used previously to successfully produce CPP with ethanol [2,3,31] and processed in the following phases ( Fig. 1):…”