Putative roles of astrocytes in general anesthesia.

General anesthetics are a mainstay of modern medicine, and although much progress has been made towards identifying molecular targets of anesthetics and neural networks contributing to endpoints of general anesthesia, our understanding of how anesthetics work remains unclear. Reducing this knowledge gap is of fundamental importance to prevent unwanted and life-threatening side-effects associated with general anesthesia. General anesthetics are chemically diverse, yet they all have similar behavioral endpoints, and so for decades research has sought to identify a single underlying mechanism to explain how anesthetics work. However, this effort has given way to the 'multiple target hypothesis' as it has become clear that anesthetics target many cellular proteins including GABAA receptors, glutamate receptors, voltage-independent K+ channels and voltage-dependent K+, Ca2+ and Na+ channels, to name a few. Yet, despite evidence that astrocytes are capable of modulating multiple aspects of neural function and express many anesthetic target proteins, they have been largely ignored as potential targets of anesthesia. The purpose of this brief review is to highlight effects of anesthetic on astrocyte processes and identify potential roles of astrocytes in behavioral endpoints of anesthesia (hypnosis, amnesia, analgesia and immobilization).