Social interaction reward in rats has anti‐stress effects
Addiction Biology. 2020-01-26; :
DOI: 10.1111/adb.12878
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Social interaction in an alternative context can be beneficial against drugs of
abuse. Stress is known to be a risk factor that can exacerbate the effects of
addictive drugs. In this study, we investigated whether the positive effects of
social interaction are mediated through a decrease in stress levels. For that
purpose, rats were trained to express cocaine or social interaction conditioned
place preference (CPP). Behavioural, hormonal, and molecular stress markers were
evaluated. We found that social CPP decreased the percentage of incorrect
transitions of grooming and corticosterone to the level of naïve untreated rats.
In addition, corticotropin-releasing factor (CRF) was increased in the bed
nucleus of stria terminalis after cocaine CPP. In order to study the modulation
of social CPP by the CRF system, rats received intracerebroventricular CRF or
alpha-helical CRF, a nonselective antagonist of CRF receptors. The subsequent
effects on CPP to cocaine or social interaction were observed. CRF injections
increased cocaine CPP, whereas alpha-helical CRF injections decreased cocaine
CPP. However, alpha-helical CRF injections potentiated social CPP. When social
interaction was made available in an alternative context, CRF-induced increase of
cocaine preference was reversed completely to the level of rats receiving cocaine
paired with alpha-helical CRF. This reversal of cocaine preference was also
paralleled by a reversal in CRF-induced increase of p38 MAPK expression in the
nucleus accumbens shell. These findings suggest that social interaction could
contribute as a valuable component in treatment of substance use disorders by
reducing stress levels.