Parallel oscillations of intracellular calcium activity and mitochondrial membrane potential in mouse pancreatic B-cells

Biochem Biophys Res Commun. 2000 Jan 7;267(1):179-83. doi: 10.1006/bbrc.1999.1921.


Insulin secretion in normal B-cells is pulsatile, a consequence of oscillations in the cell membrane potential (MP) and cytosolic calcium activity ([Ca(2+)](c)). We simultaneously monitored glucose-induced changes in [Ca(2+)](c) and in the mitochondrial membrane potential DeltaPsi, as a measure for ATP generation. Increasing the glucose concentration from 0.5 to 15 mM led to the well-known hyperpolarization of DeltaPsi and ATP-dependent lowering of [Ca(2+)](c). However, as soon as [Ca(2+)](c) rose due to the opening of voltage-dependent Ca(2+) channels, DeltaPsi depolarized and thereafter oscillations in [Ca(2+)](c) were parallel to oscillations in DeltaPsi. A depolarization or oscillations of DeltaPsi cannot be evoked by a substimulatory glucose concentration, but Ca(2+) influx provoked by 30 mM KCl was followed by a depolarization of DeltaPsi. The following feedback loop is suggested: Glucose metabolism via mitochondrial ATP production and closure of K(+)(ATP) channels induces an increase in [Ca(2+)](c). The rise in [Ca(2+)](c) in turn decreases ATP synthesis by depolarizing DeltaPsi, thus transiently terminating Ca(2+) influx.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Calcium / metabolism*
  • Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone / pharmacology
  • Cells, Cultured
  • Female
  • Glucose / pharmacology
  • Intracellular Membranes / drug effects
  • Intracellular Membranes / physiology*
  • Islets of Langerhans / physiology*
  • Kinetics
  • Membrane Potentials / drug effects
  • Membrane Potentials / physiology
  • Mice
  • Mice, Inbred Strains
  • Mitochondria / drug effects
  • Mitochondria / physiology*
  • Oscillometry
  • Sodium Azide / pharmacology


  • Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone
  • Sodium Azide
  • Glucose
  • Calcium