ATP-Sensitive K+ Channel: Properties, Occurrence, Role in Regulation of Insulin Secretion

A K+ channel inhibited by cytosolic ATP (KATP channel) was first demonstrated in cardiac cells by Noma (1983). This channel is also inhibited by sulfonylureas, is highly K+ selective, and has a single channel conductance of 80 pS when measured in symmetrical high K+ solutions (Trube and Hescheler 1984; Kakei and Noma 1984; Belles et al. 1987). Noma’s discovery prompted the identification of a K+ channel with similar properties in pancreatic β-cells (Cook and Hales 1984; Ashcroft et al. 1984; Sturgess et al. 1985), skeletal muscle (Spruce et al. 1985, 1987; Woll et al. 1989), smooth muscle (Nelson et al. 1990; Kajioka et al. 1991) and nerve cells (Jonas et al. 1991; Politi and Rogawski 1991; Ohno-Shosaku and Yamamoto 1992). This chapter confines itself to this K+ channel, and we use the term KATP channel with this restriction. Other types of ATP-sensitive K+ channels have been found in various cells (Ashcroft and Ashcroft 1990). Several reviews concerning the KATP channel have been published during the recent years (Ashcroft 1988; Ashcroft and Rorsman 1991; Ashford 1990; Ashcroft and Ashcroft 1990; Rorsman and Trube 1990; Dunne and Petersen 1991; Nichols and Lederer 1991; Davies et al. 1991; Noma and Takano 1991; Panten et al. 1992; Ashcroft and Ashcroft 1992). Where appropriate, these reviews are cited to limit the primary references.