Susceptibility and resilience to the effects of chronic psychosocial stress in adolescence: participation of the neuronal nitric oxide synthase (nNOS)

Abstract

Exposure to traumatic events during the first stages of life can lead to behavioral changes. Teenagers are especially vulnerable to social stressors, significantly influencing brain development. In this period of life, bullying is one of the most frequent social stressors and can lead to the development of psychiatric disorders such as depression and anxiety. The social defeat model in mice is a good animal model to study the effects of psychosocial stress, because it reflects the etiology, the phenotypic expression, and the therapeutic response to these disorders. In addition, as observed in humans, not all animals exposed to prolonged social stress are susceptible to the development of anhedonia and social phobia. There is a resistant population to these damaging effects, and these animals are referred to as "resilient". The neurobiology of resilience and susceptibility to chronic stress can elucidate mechanisms involved in depression and anxiety and thus identify new molecules and potential therapeutic targets. The aim of this study is to identify and study adolescent male mice susceptible and resilient to the emotional (anhedonic) effects of social defeat. We chose the neuronal nitric oxide synthase (nNOS) as the molecular target to be investigated in these populations. Preliminary results of our lab have suggested changes in nNOS gene expression in the hippocampus of male adolescent mice after psychosocial stress. (AU)