Social stress blocks energy conservation in rats exposed to an oxytocin-injected cage mate.

We previously found stress-reduction in rats exposed to an oxytocin-injected cage-mate. Olfactory impairment and oxytocin antagonist treatment blocked the effect. Here, we investigated effects of social stress on the exposure-induced response and exposure on amygdaloid oxytocin concentrations. CT concentrations in exposed olfactorily impaired, CT antagonist-treated and saline-injected unexposed rats were reduced, compared to the significantly higher level in untreated and exposed saline-injected rats. Saline injections and group mixing enhanced heat dissipation. Exposure abolished the injection-induced, but not mixing-induced stress response, most likely via a social stress induced effect on the oxytocin-injected rat. The difference in exposure responsivity may relate to recognition, stress type and intensity affecting different stress-response systems. The mechanism could reinforce social attachment.