Original investigation

Psychopharmacology

, Volume 183, Issue 3, pp 341-349

Effects of unconditioned and conditioned social defeat on alcohol self-administration and reinstatement of alcohol seeking in rats

  • D. FunkAffiliated withDepartment of Neurosciences, Center for Addiction and Mental Health (CAMH) Email author 
  • , S. HardingAffiliated withDepartment of Neurosciences, Center for Addiction and Mental Health (CAMH)
  • , W. JuzytschAffiliated withDepartment of Neurosciences, Center for Addiction and Mental Health (CAMH)
  • , A. D. LêAffiliated withDepartment of Neurosciences, Center for Addiction and Mental Health (CAMH)Department of Pharmacology and Psychiatry, University of Toronto

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Abstract

Rationale and objectives

We and others have shown that a stressor commonly used in laboratory studies, intermittent footshock, reinstates alcohol seeking in a rat relapse model. The effects of more ethologically relevant stressors on reinstatement have not been examined. Here, we characterized the effects of social defeat (a naturalistic stressor) or a cue associated with the defeat experience on reinstatement of alcohol seeking. We also examined the effect of unconditioned and conditioned social defeat on alcohol self-administration.

Methods

Rats were trained to self-administer alcohol (12% w/v, 1 h day−1), and after stable responding, one group of animals received five exposures to social defeat paired with peppermint odor prior to daily self-administration sessions. After three more self-administration sessions, these rats were tested for the effects of the peppermint odor cue on self-administration. In another group of rats, the effects of three daily exposures to social defeat paired with peppermint odor on extinction of responding were examined. After further extinction sessions, the effect of the odor cue on reinstatement was tested in these animals. The acute effect of social defeat on reinstatement was examined in another group of animals.

Results

Acute exposure to social defeat decreased alcohol self-administration, reduced rates of responding during extinction, and did not reinstate alcohol seeking. Exposure to a discrete odor cue previously paired with social defeat decreased alcohol self-administration but induced modest reinstatement of alcohol seeking.

Conclusions

Results provide the first demonstration of reinstatement of alcohol seeking by a cue paired with social defeat and are also in agreement with previous findings on the suppressive effect of social defeat stress on alcohol self-administration.

Keywords

Social defeat Conditioning Alcohol self-administration Craving Reinstatement Relapse Stress