Dopaminergic Neurons in the Ventral Tegmental-Prelimbic Pathway Promote the Emergence of Rats from Sevoflurane Anesthesia.

Dopaminergic neurons in the ventral tegmental area (VTA) play an important role in cognition, emergence from anesthesia, reward, and aversion, and their projection to the cortex is a crucial part of the "bottom-up" ascending activating system. The prelimbic cortex (PrL) is one of the important projection regions of the VTA. However, the roles of dopaminergic neurons in the VTA and the VTA-PrL pathway under sevoflurane anesthesia in rats remain unclear. In this study, we found that intraperitoneal injection and local microinjection of a dopamine D1 receptor agonist (Chloro-APB) into the PrL had an emergence-promoting effect on sevoflurane anesthesia in rats, while injection of a dopamine D1 receptor antagonist (SCH23390) deepened anesthesia. The results of chemogenetics combined with microinjection and optogenetics showed that activating the VTA-PrL pathway prolonged the induction time and shortened the emergence time of anesthesia. These results demonstrate that the dopaminergic system in the VTA has an emergence-promoting effect and that the bottom-up VTA-PrL pathway facilitates emergence from sevoflurane anesthesia.