Microfluorometric analysis of Cl- permeability and its relation to oscillatory Ca2+ signalling in glucose-stimulated pancreatic beta-cells

Cell Signal. 2000 Dec;12(11-12):781-6. doi: 10.1016/s0898-6568(00)00122-4.

Abstract

The cytoplasmic concentrations of Cl-([Cl-]i) and Ca2+ ([Ca2+]i) were measured with the fluorescent indicators N-(ethoxycarbonylmethyl)-6-methoxyquinilinum bromide (MQAE) and fura-2 in pancreatic beta-cells isolated from ob/ob mice. Steady-state [Cl-]i in unstimulated beta-cells was 34 mM, which is higher than expected from a passive distribution. Increase of the glucose concentration from 3 to 20 mM resulted in an accelerated entry of Cl- into beta-cells depleted of this ion. The exposure to 20 mM glucose did not affect steady-state [Cl-]i either in the absence or presence of furosemide inhibition of Na+, K+, 2 Cl- co-transport. Glucose-induced oscillations of [Ca2+]i were transformed into sustained elevation in the presence of 4,4' diisothiocyanato-dihydrostilbene-2,2'-disulfonic acid (H2DIDS). A similar effect was noted when replacing 25% of extracellular Cl- with the more easily permeating anions SCN-, I-, NO3- or Br-. It is concluded that glucose stimulation of the beta-cells is coupled to an increase in their Cl- permeability and that the oscillatory Ca2+ signalling is critically dependent on transmembrane Cl- fluxes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid / analogs & derivatives*
  • 4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid / pharmacology
  • Animals
  • Anions / pharmacology
  • Calcium / metabolism*
  • Calcium Channel Blockers / pharmacology
  • Calcium Signaling / drug effects*
  • Cell Membrane Permeability / drug effects
  • Cells, Cultured
  • Chlorides / metabolism*
  • Chlorides / pharmacology
  • Electric Conductivity
  • Fluorescence
  • Fluorometry / methods
  • Fura-2
  • Furosemide / pharmacology
  • Gallopamil / pharmacology
  • Glucose / pharmacology*
  • Islets of Langerhans / cytology
  • Islets of Langerhans / drug effects*
  • Islets of Langerhans / metabolism*
  • Mice
  • Mice, Mutant Strains
  • Obesity / genetics
  • Quinolinium Compounds

Substances

  • Anions
  • Calcium Channel Blockers
  • Chlorides
  • Quinolinium Compounds
  • N-(ethoxycarbonylmethyl)-6-methoxyquinolinium
  • Gallopamil
  • dihydro-DIDS
  • Furosemide
  • Glucose
  • 4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid
  • Calcium
  • Fura-2