Dorsomedial hypothalamus cold-sensitive neurons drive shivering thermogenesis

Shivering thermogenesis is the bodys response to cold, where the hypothalamus signals muscle contractions to generate heat. While cold-responsive neurons in the preoptic area and ventromedial hypothalamus are known to regulate thermogenesis, the specific neurons driving shivering thermogenesis remain unclear. Here, we identify a subset of VGLUT2-positive excitatory neurons in the dorsomedial hypothalamic nucleus (DMHVglut2), enriched with Calbindin D28k (CALB1) expression (DMHCalb1/Vglut2), that selectively initiate cold-evoked shivering thermogenesis. When core body temperature (Tcore) dropped to 33{degrees}C, c-Fos expression peaked in the DMH. RNA sequencing of retrogradely labeled DMH neurons, traced through cervical muscles, revealed CALB1 and VGLUT2 expression in these neurons. Activation or inhibition of DMHCalb1/Vglut2 neurons specifically affected shivering thermogenesis, while modulation of DMHVglut2 neurons influenced Tcore through both shivering and non-shivering thermogenesis. Activation of CALB1-negative, VGLUT2-positive DMH neurons impacted non-shivering thermogenesis, confirming that DMHCalb1/Vglut2 neurons drive shivering. DMHCalb1/Vglut2 neurons exhibited cold temperature-dependent firing, with 23% peaking at 35{degrees}C, 27% at 34{degrees}C, and 50% at 33{degrees}C, explaining the hierarchical increase in shivering intensity during cold exposure. Their activation relies on the cold receptor TRPM8. Knockdown of TRPM8 expression in DMHCalb1/Vglut2 neurons in vivo reduced cold-evoked shivering. Pharmacological activation or inhibition of TRPM8 in DMHCalb1/Vglut2 neurons in vitro, respectively, reduced or enhanced cold temperature-dependent firing. These effects were eliminated when TRPM8 was knocked down in DMHCalb1/Vglut2 neurons. Inhibition of DMHCalb1/Vglut2 neurons prevented counteractive shivering, enabled rapid hypothermia, and protected the ischemic brain. This work revealed the central control of shivering and provided a potential strategy for controlled therapeutic hypothermia.