In vivo imaging reveals a synchronized correlation among neurotransmitter dynamics in propofol or sevoflurane anesthesia

General anesthesia is widely applied in clinical practice. However, the precise mechanism of loss of consciousness induced by general anesthetics remains unknown. Here, we measured the dynamics of five neurotransmitters, including γ-aminobutyric acid, glutamate, norepinephrine, acetylcholine, and dopamine in the medial prefrontal cortex and the primary visual cortex of C57BL/6 mice through in vivo fiber photometry and genetically encoded neurotransmitter sensors under anesthesia to reveal the mechanism of general anesthesia from the perspective of neurotransmitters. We discovered that the concentrations of γ-aminobutyric acid, glutamate, norepinephrine, and acetylcholine in the cortex increased during propofol-induced loss of consciousness. The dopamine concentration did not change following the hypnotic dose of propofol; however, the concentration increased significantly following surgical doses of propofol anesthesia. Notably, the concentrations of the five neurotransmitters generally decreased during sevoflurane-induced loss of consciousness. Moreover, in the non-anesthesia groups, the neurotransmitter dynamic networks were not synchronized; however, in the anesthetic groups, the neurotransmitter dynamic networks were highly synchronized. These data revealed that neurotransmitter dynamics network synchronization may cause anesthetic-induced loss of consciousness.