Mg2+ and ATP-dependence of volume-sensitive Cl- channels in human epithelial cells.
During osmotic cell swelling whole-cell Cl- currents were recorded in cultured human small intestinal epithelial cells (Intestine 407). When intracellular ATP was depleted, swelling-induced Cl- currents were abolished. Increases in intracellular free ATP enhanced the Cl- current in a concentration-dependent manner. The presence of intracellular free Mg2+ ions suppressed the current. Non-hydrolyzable ATP analogs (AMP-PNP and ATP gamma S), ADP, and GTP could substitute for ATP. Thus, it is concluded that ATP plays an indispensable role in activation of the volume-sensitive Cl- channel without hydrolysis and that intracellular Mg2+ is an additional regulator for volume-sensitive Cl- channels in Intestine 407 cells.
Oiki
S
S
Department of Cellular and Molecular Physiology, National Institute for Physiological Sciences, Okazaki, Japan.
Kubo
M
M
Okada
Y
Y
D000244:Adenosine Diphosphate / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000494:pharmacology; D002478:Cells, Cultured; D018118:Chloride Channels / Q000502:physiology*; D004848:Epithelium / Q000502:physiology*; D006801:Humans; D007422:Intestines / Q000502:physiology; D008274:Magnesium / Q000494:pharmacology; D014882:Water-Electrolyte Balance
D018118:Chloride Channels; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D008274:Magnesium