Sociopsychological stress activates hypothalamo‐medullary neurons that drive brown adipose tissue thermogenesis and hyperthermia (1130.6)

Abstract

Psychological stress induces hyperthermia in many mammalian species. We have shown that psychological stress induces heat production in brown adipose tissue (BAT) through activation of sympathetic premotor neurons in the rostral medullary raphe (rMR) (Lkhagvasuren et al., 2011). The present study investigated the central circuit mechanism that drives stress signaling to the BAT‐controlling premotor neurons. Rats exposed to social defeat stress, a sociopsychological stress model, exhibited increases in BAT and abdominal temperature. This stress response was eliminated by a nanoinjection of AP5 and CNQX, glutamate receptor antagonists, into the rMR. This stress activated neurons in the dorsomedial hypothalamus (DMH) that directly project to the rMR and inhibition of neurons in the DMH with muscimol injections eliminated the stress‐induced BAT thermogenesis and hyperthermia. Supporting functional contribution of the DMH‐rMR monosynaptic pathway in the stress‐driven BAT thermogenesis, in vivo optogenetic stimulation of DMH‐derived nerve endings in the rMR elicited BAT thermogenesis, which was blocked by antagonizing glutamate receptors in the rMR. These results indicate that the DMH‐rMR glutamatergic monosynaptic pathway likely mediates stress signaling to drive BAT thermogenesis, contributing to psychological stress‐induced hyperthermia.