Potassium Channels in Skeletal Muscle

Abstract

Several different potassium-selective channels have been described1,2 since 1902, when Julius Bernstein postulated the existence of a selective potassium permeability in excitable cell membranes.3 This diversity results from the expression of different or related genes, from the alternative splicing of a primary transcript, or from posttranslational modifications. In addition, the assembling of different channel proteins into heteromultimeric species and tissue-specific expression of different channel types have been proposed.4,5 Potassium channels can be found in almost all eukaryotic cells. Various types of potassium channels may be present in the same cell, while different cells may contain similar types. The functional role of all types of potassium channels is to lower the excitability of the cell1 and, although different channels play different roles in stabilizing the cell membrane, the individual contribution of a specific channel type to the total ionic current is often difficult to determine.