The impact of social conflict on cardiac activity

Environmental challenges of various nature, either predominantly physical or psychological, can affect cardiovascular function in a significant manner. In mammalian species where individuals live in highly organized groups (for instance primates and rodents), social competition represents a relevant, recurring stressor, especially among males. Therefore, the study of animal models of social conflict can provide valuable clues in understanding the link between stress factors and cardiovascular pathophysiology in humans1,2. In rats, robust autonomic, neuroendocrine and behavioral changes are observed when a male rat is exposed to a social defeat episode. Social defeat is classically obtained by exposing the experimental animal to the aggression of a territorial male conspecific. Short-term effects include heart rate, blood pressure and body temperature raises, together with plasma catecholamine and corticosterone elevations. In this chapter we summarize the results of a few experiments performed in male wild type rats, in which we investigated the acute effects of social challenges on the autonomic regulation of cardiac rhythm and the susceptibility to cardiac anfiythmias.