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

Michael Eberhardson, Steven Patterson, Eva Grapengiesser*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

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.
Original languageEnglish
Pages (from-to)781-786
Number of pages6
JournalCellular signalling
Volume12
Issue number11-12
DOIs
Publication statusPublished - Dec 2000

Keywords

  • Ca2+ oscillations
  • Cytoplasmic chloride
  • Furosemide
  • Glucose
  • H2DIDS
  • MQAE
  • Pancreatic β-cell

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