No abstract

Physical activity can combat detrimental effects of stress. The current study examined the potential protective effects of exercise against a combination of social isolation and chronic mild stress (CMS) in a prairie vole model. Female voles were isolated for 4 weeks, with the addition of CMS during the final 2 weeks. Half of the voles were allowed access to a running wheel during this final 2 weeks, while the other half remained sedentary. Animals underwent behavioral tests to assess depressive- and anxiety-behaviors. In a subset of animals, plasma was collected 10 minutes after behavioral testing for corticosterone analysis. In a separate subset, brains were collected 2 hours after behavioral testing for cFos analysis in the paraventricular nucleus (PVN). Voles in the exercise group displayed significantly lower depressive- and anxiety-behaviors, and displayed significantly lower corticosterone levels, compared to animals in the sedentary group. There was no difference in PVN cFos activity between groups. Interestingly, animals that moderately exercised displayed lower levels of depressive-behavior and attenuated corticosterone reactivity compared to animals in the low and high activity subgroups. These findings suggest that physical activity can protect against a combination of social and environmental stressors.

EE and re-pairing reversed the negative behavioral and cardiovascular consequences associated with social isolation.

No abstract

Negative social experiences influence both depression and cardiovascular dysfunction. Many individuals who experience negative mood states or cardiovascular conditions have limited social support. Therefore, investigation of drug treatments that may protect against the consequences of social stress will aid in designing effective treatment strategies. The current study used an animal model to evaluate the protective effect of sertraline administration on behavioral and cardiovascular consequences of social stress. Specifically, male prairie voles (Microtus ochrogaster), which are socially monogamous rodents that share several behavioral and physiological characteristics with humans, were isolated from a socially-bonded female partner, and treated with sertraline (16 mg/kg/day, ip) or vehicle during isolation. Unexpectedly, sertraline did not protect against depression-relevant behaviors, and it was associated with increased shortand long-term heart rate responses. However, sertraline administration improved heart rate variability recovery following a behavioral stressor, including increased parasympathetic regulation, and altered long-term neuronal activity in brain regions that modulate autonomic control and stress reactivity. These results indicate that sertraline may partially protect against the consequences of social stressors, and suggest a mechanism through which sertraline may beneficially influence neurobiological control of cardiac function.