Does social interaction reward have an anti-stress effect?

Switching the preference of the substance dependent individual toward non-drug related activities remains one of the great challenges that confront drug dependence therapy. Beneficial social interaction can positively affect personal relationships and may serve as an alternate natural reward to drug use. However, the mechanisms underlying these positive effects of social interaction reward are not known. Our data have recently shown that social interaction reward decreased p38 (stress activated protein kinase) activation in the nucleus accumbens. Here, we suggest that positive social reward has an anti-stress role that reduces drug abuse if offered in an alternative context. To test this hypothesis, we will first analyze the expression of corticotropine releasing factor (CRF) and its receptors in key areas involved in stress response / and corticosterone plasma levels after the expression of cocaine conditioned place preference (CPP) and social interaction conditioned place preference. We will investigate then the effects of intra cerebro ventricular injections (icv) of CRF or CRF receptor antagonist on cocaine/social reward. We will also study the impact of CRF receptor antagonist on p38 activation in order to search for an eventual relation between these two stress systems. Further, we will assess the effects of icv injections of p38 inhibitor on cocaine /social reward. Finally, using p38 beta KO mice, we will identify which isoform of p38 (alpha or beta) may be implicated in cocaine/social reward and stress/anxiety related behaviors. This proposal will help us to investigate the role anti stress of social interaction reward and to highlight for the first time direct correlations and relations between the CRF system and p38 MAPK regulation in the brain. It will also show up the role of p38 in stress behaviors beyond the cellular level and help to further identify its implication in drug addiction and stress behaviors through the characterization of the behavioral profile of beta p38 KO mice. This knowledge may be instrumental for the identification of new targets for the development of new medication against drug abuse.

Can spending time with a friend have anti-stress effects? We already knew that switching the preference of the substance dependent individual toward non-drug related activities remains one of the great challenges that confront drug dependence therapy. Beneficial social interaction can positively affect personal relationships and may serve as an alternative to drug abuse. However, the mechanisms underlying these positive effects of social interaction reward are not known. Our data have recently shown that social interaction reward decreased p38 (stress activated protein kinase) activation in a region of the brain called nucleus accumbens that plays a role in reward. In this project, we suggested that positive social reward has an anti-stress role that reduces drug abuse if offered in an alternative context. We could show that social interaction reduced stress markers in the brain as well as stress hormone. When we increased stress by injecting the stress corticorsterone releasing factor in the brain, social interaction could resist the effects of stress. Furthermore, when social interaction is made available as an alternative to drug such as cocaine and stress, it reversed the preference to the cocaine and reduced stress markers to the level of unstressed conspecific. These results show that spending time with a friend in a non-drug related context can reduce the preference to drug-related context through reducing stress effects. The beneficial anti-stress effect of social interaction on the prevention of drug abuse and the reorientation of substance-dependent individuals behavior toward non-drug related activities is interesting for neuroscientists, cognitive psychologists, and psychotherapists. This knowledge may be also instrumental for the identification of new targets for the development of new medication against drug abuse.