Dopaminergic Neurons in the Ventral Tegmental Area to the Parabrachial Nucleus Promote the Emergence of Rats from Propofol Anesthesia

Abstract

Abstract Since the clinical introduction of general anesthesia, its underlying mechanisms have not been fully elucidated. The ventral tegmental area (VTA) and parabrachial nucleus (PBN) play pivotal roles in the mechanisms underlying general anesthesia. However, whether dopaminergic (DA) projections from the VTA to the PBN play a role in mediating the effects of general anesthesia is unclear. We microinjected 6-hydroxydopamine into the PBN to damage DA neurons and found a prolonged recovery time from propofol anesthesia. We used calcium fiber photometry recording to explore the activity of PBN DA neurons. Then, we used chemogenetic or optogenetic approaches to activate the VTADA-PBN pathway, shorten the propofol anesthesia emergence time, and inhibit this pathway to prolong the emergence time. These data indicate the crucial involvement of PBN DA neurons in regulating propofol anesthesia, while the activation of the VTADA-PBN pathway facilitates the emergence from propofol anesthesia.