Calcium channels - Basic aspects of their structure, function and gene encoding; anesthetic action on the channels - A review

Abstract

Purpose: To review recent findings concerning Ca2+ channel subtype/structure/function from electrophysiological and molecular biological studies and to explain Ca2+ channel diseases and the actions of anesthetics on Ca2+ channels. Source: The information was obtained from articles published recently and from our published work. Principal findings: Voltage-dependent Ca2+ channels serve as one of the important mechanisms for Ca2+ influx into the cells, enabling the regulation of intracellular concentration of free Ca2+. Recent advances both in electrophysiology and in molecular biology have made it possible to observe channel activity directly and to investigate channel functions at molecular levels. The Ca2+ channel can be divided into subtypes according to electrophysiological characteristics, and each subtype has its own gene. The L-type Ca2+ channel is the target of a large number of clinically important drugs, especially dihydropyridines, and binding sites of Ca2+ antagonists have been clarified. The effects of various kinds of anesthetics in a variety of cell types have been demonstrated, and some clinical effects of anesthetics can be explained by the effects on Ca2+ channels. It has recently become apparent that some hereditary diseases such as hypokalemic periodic paralysis result from calcium channelopathies. Conclusion: Recent advances both in electrophysiology and in molecular biology have made it possible to clarify the Ca2+ channel structures, functions, genes, and the anesthetic actions on the channels in detail. The effects of anesthetics on the Ca2+ channels either of patients with hereditary channelopathies or using gene mutation techniques are left to be discovered.