[Electrophysiological approach to mechanisms for actions of general anesthetics]

Although general anesthetics were first used more than 160 years ago, their mechanisms have remained mysterious. During the past decade, significant progress in our understanding of general anesthetic action at the cellular and network system levels has been made. Our recent work demonstrates (a) that intravenous anesthetics, but not volatile agents, enhance the discharge of GABA from presynaptic terminals, (b) that intravenous anesthetics produce frequency-dependent modification (FDM) of anesthesia, and (c) that FDM is responsible for the unsuccessful immobilization or hypnosis during intravenous anesthesia. In addition, we review the development of hypothesis for anesthetic action, non-specific versus specific action, cutoff phenomenon in n-alcohols, and anesthesiological approach to consciousness.