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World J Crit Care Med. Jun 4, 2012; 1(3): 80-93
Published online Jun 4, 2012. doi: 10.5492/wjccm.v1.i3.80
General anesthesia mediated by effects on ion channels
Cheng Zhou, Jin Liu, Xiang-Dong Chen
Cheng Zhou, Jin Liu, Xiang-Dong Chen, Department of Anesthesiology, Laboratory of Anesthesia and Critical Care Medicine, Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu 610041, Sichuan Province, China
Author contributions: Originally written by Zhou C and revised by Liu J and Chen XD.
Correspondence to: Xiang-Dong Chen, MD, PhD, Professor of Department of Anesthesiology, Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu 610041, Sichuan Province, China. xiangdong_chen@yahoo.com
Telephone: +86-28-85164040 Fax: +86-28-85164038
Received: August 20, 2011
Revised: October 24, 2011
Accepted: May 25, 2012
Published online: June 4, 2012
Abstract

Although it has been more than 165 years since the first introduction of modern anesthesia to the clinic, there is surprisingly little understanding about the exact mechanisms by which general anesthetics induce unconsciousness. As a result, we do not know how general anesthetics produce anesthesia at different levels. The main handicap to understanding the mechanisms of general anesthesia is the diversity of chemically unrelated compounds including diethyl ether and halogenated hydrocarbons, gases nitrous oxide, ketamine, propofol, benzodiazepines and etomidate, as well as alcohols and barbiturates. Does this imply that general anesthesia is caused by many different mechanisms Until now, many receptors, molecular targets and neuronal transmission pathways have been shown to contribute to mechanisms of general anesthesia. Among these molecular targets, ion channels are the most likely candidates for general anesthesia, in particular γ-aminobutyric acid type A, potassium and sodium channels, as well as ion channels mediated by various neuronal transmitters like acetylcholine, amino acids amino-3-hydroxy-5-methyl-4-isoxazolpropionic acid or N-methyl-D-aspartate. In addition, recent studies have demonstrated the involvement in general anesthesia of other ion channels with distinct gating properties such as hyperpolarization-activated, cyclic- nucleotide-gated channels. The main aim of the present review is to summarize some aspects of current knowledge of the effects of general anesthetics on various ion channels.

Keywords: General anesthesia; Ion channels; γ-amino-butyric acid type A receptors; Hyperpolarization activated cyclic nucleotide; Potassium channels; Glutamatergic ion channels; Sodium channels