Astrocytes modulate a specific paraventricular thalamus-prefrontal cortex projection to enhance consciousness recovery from anesthesia

Current anesthetic theory is mostly based on neurons and/or neuronal circuits. A role for astrocytes also has been shown in promoting recovery from volatile anesthesia, while the exact modulatory mechanism and/or the molecular target in astrocytes is still unknown. In this study, by animal models in male mice and electrophysiological recordings in vivo and in vitro, we found that activating astrocytes of paraventricular thalamus (PVT) and/or knocking down PVT astrocytic Kir4.1 promoted the consciousness recovery from sevoflurane anesthesia. Single-cell RNA sequencing of PVT reveals two distinct cellular subtypes of glutamatergic neurons: PVT GRM and PVT ChAT neurons. Patch-clamp recording results proved astrocytic Kir4.1-mediated modulation of sevoflurane on PVT mainly worked on PVT ChAT neurons, which projected mainly to the mPFC. In summary, our findings support the novel conception that there is a specific PVT-prefrontal cortex projection involved in consciousness recovery from sevoflurane anesthesia, which mediated by the inhibition of sevoflurane on PVT astrocytic Kir4.1 conductance. Significance Statement How volatile anesthetics work is not fully understood. Here, we demonstrate that the commonly used volatile anesthetic sevoflurane can inhibit astrocytic Kir4.1 conductance in PVT, which enhances neuronal firing of PVT neurons. Additionally, by single-cell sequencing, cholinergic neurons in the PVT (PVT ChAT ) are the neuronal substrates for astrocytic modulation in volatile anesthesia, which directly project to prefrontal cortex. Behaviorally, the modulation of astrocytes on PVT ChAT promotes electroencephalogram (EEG) transition of prefrontal cortex; and then accelerates emergence from sevoflurane anesthesia. In summary, this study is the first to identify that astrocytic Kir4.1 in wakeful nuclei is involved in consciousness recovery from volatile anesthetics, as well as the subcellular mechanism.