Role of the ventral tegmental area in general anesthesia.

The ventral tegmental area (VTA), located in the midbrain, plays a pivotal role in the regulation of many important behaviors, such as reward, addiction, aversion, memory, learning, and sleep-wakefulness cycles. The majority of VTA neurons are dopaminergic neurons, although there is a significant proportion of GABAergic neurons and few glutamatergic neurons. These neuronal types project to different brain regions, thus mediating various biological functions. Therefore, the diverse roles of the VTA might depend on its heterogeneous neuronal types and projecting circuits. General anesthesia and sleep-wakefulness cycles share the feature of reversible loss of consciousness, and several common neural mechanisms underlie these two conditions. In addition to the well-known regulatory role of VTA in sleep-wakefulness, emerging evidence has demonstrated that VTA activity is also associated with promoting emergence from general anesthesia. Herein, we reviewed the literature and summarized the evidence regarding the modulation of the VTA by general anesthesia in rodents, which will improve the understanding of the modulatory mechanism of the VTA in general anesthesia.