GABAergic neurons in the dorsomedial hypothalamus regulate states of consciousness in sevoflurane anesthesia

The neural inhibitory gamma-aminobutyric acid (GABA) system in the regulation of anesthetic consciousness is heterogeneous, and the medial hypothalamus (MH), consisting of ventromedial hypothalamus (VMH) and dorsomedial hypothalamus (DMH), plays an important role in sleep and circadian rhythm. However, the role of MH GABAergic neurons (MH(GABA)) in anesthesia remains unclear. In this study, we used righting reflex, electroencephalogram (EEG), and arousal behavioral score to evaluate the sevoflurane anesthesia. Activation of MH(GABA) or DMH(GABA) neurons prolonged the anesthesia induction time, shortened the anesthesia emergence time, and induced EEG arousal and body movement during anesthesia; meanwhile, VMH(GABA) neurons activated only induced EEG changes during 1.5% sevoflurane anesthesia. Furthermore, inhibition of DMH(GABA) neurons significantly deepened sevoflurane anesthesia. Therefore, DMH(GABA) neurons exert a strong emergence-promoting effect on induction, maintenance, and arousal during sevoflurane general anesthesia, which helps to reveal the mechanism of anesthesia.