ATP regulates sodium channel kinetics in pancreatic islet beta cells

J Membr Biol. 2013 Feb;246(2):101-7. doi: 10.1007/s00232-012-9506-7. Epub 2013 Jan 8.

Abstract

Pancreatic beta cells act as glucose sensors, in which intracellular ATP ([ATP](i)) are altered with glucose concentration change. The characterization of voltage-gated sodium channels under different [ATP](i) remains unclear. Here, we demonstrated that increasing [ATP](i) within a certain range of concentrations (2-8 mM) significantly enhanced the voltage-gated sodium channel currents, compared with 2 mM cytosolic ATP. This enhancement was attenuated by even high intracellular ATP (12 mM). Furthermore, elevated ATP modulated the sodium channel kinetics in a dose-dependent manner. Increased [ATP](i) shifted both the current-voltage curve and the voltage-dependent inactivation curve of sodium channel to the right. Finally, the sodium channel recovery from inactivation was significantly faster when the intracellular ATP level was increased, especially in 8 mM [ATP](i), which is an attainable concentration by the high glucose stimulation. In summary, our data suggested that elevated cytosolic ATP enhanced the activity of Na(+) channels, which may play essential roles in modulating β cell excitability and insulin release when blood glucose concentration increases.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphate / metabolism*
  • Animals
  • Blood Glucose / metabolism
  • Electrophysiology
  • Humans
  • In Vitro Techniques
  • Insulin-Secreting Cells / metabolism*
  • Kinetics
  • Male
  • Mice
  • Pancreas / metabolism

Substances

  • Blood Glucose
  • Adenosine Triphosphate