Advertisement

Heterogeneity of β-Cell Ca2+ Responses to Glucose

  • P. Smith
  • P. J. Millard
  • C. M. S. Fewtrell
  • F. M. Ashcroft
Chapter
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 426)

Abstract

Insulin secretion is initiated by an increase in the cytoplasmic calcium concentration. Glucose metabolism stimulates this rise in [Ca2+]i by closing ATP-sensitive K-channels in the plasma membrane, thereby producing membrane depolarisation, activation of voltage-gated Ca2+ channels and influx of extracellular Ca2+ (Ashcroft & Rorsman, 1989). Electrical activity, and thus Ca2+ influx, occurs in bursts and gives rise to synchronous oscillations in [Ca2+]i (Santos et al., 1991; Valdeolmillos et al., 1989). Considerable heterogeneity in the [Ca2+]i oscillatory behaviour of single β-cells has been reported (Pralong et al., 1991; Hell-man et al., 1992). However, within an islet (which contains > 1000 β-cells) the cells appear to oscillate in synchrony (Valdeolmillos et al., 1993), a feature which no doubt results from the well-established electrical coupling between β-cells (Eddiestone et al., 1984). Most previous studies have focused on the response of the β-cell or islet to a single glucose concentration. In this paper, therefore, we have examin ed the relationship between glucose and intracellular Ca2+ over a wide range of glucose concentrations, using imaging techniques to record simultaneous responses from a population of β-cells.

Keywords

Insulin Secretion Pyridine Nucleotide Increase Glucose Concentration Synchronous Oscillation Tumor Mast Cell 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Ashcroft F. M. and Rorsman P. (1989) Electrophysiology of the pancreatic β-cell. Prog. Biophys. Molec. Biol. 54: 87–143.CrossRefGoogle Scholar
  2. Cleveland P. L., Millard P. J., Showell H. J. and Fewtrell C. M. S. (1993) Tenidap: a novel inhibitor of calcium influx in a mast cell line. Cell Calcium 14: 1–16.PubMedCrossRefGoogle Scholar
  3. Eddlestone G. T., Gonçalves A., Bangham J. A. and Rojas E. (1984) Electrical coupling between cells in islets of Langerhans from mouse. J. Memb. Biol. 77: 1–14.CrossRefGoogle Scholar
  4. Hellman B., Gylfe E., Grappengeisser E., Lund P. E. and Marcström A. (1992) Cytoplasmic calcium and insulin secretion. In Nutrient Regulation of Insulin Secretion. Ed. P. Flatt. pp. 213-246.Google Scholar
  5. Hiriart M. and Matteson D. R. (1988) Na channels and two types of Ca channels in rat pancreatic β-cells identified with the reverse haemolytic plaque assay. J. Gen. Physiol. 91: 617–639.PubMedCrossRefGoogle Scholar
  6. Millard P. J., Ryan T. A., Webb W. W. and Fewtrell C. (1989) Immunoglobulin E cross-linking induces oscillations in intracellular free ionized calcium in individual tumor mast cells. J. Biol. Chem. 264: 19730–19739.PubMedGoogle Scholar
  7. Pralong W. F., Bartley C. and Wollheim C. B. (1990) Single islet beta-cell stimulation by nutrients: relationship between pyridine nucleotides, cytosolic Ca2+ and secretion. EMBO J. 9: 53–60.PubMedGoogle Scholar
  8. Salomon D. and Meda P. (1986) Heterogeneity and contact-dependent regulation of hormone secretion by individual B-cells. Exp. Cell. Res. 162: 507–520.PubMedCrossRefGoogle Scholar
  9. Santos R. M., Rosario L. M., Nadal A., Garcia-Sancho J., Soria B. and Valdeolmillos M. (1991) Widespread synchronous [Ca2+]i oscillations due to bursting elecrical activity in single pancreatic islets. Pflügers Arch 418: 417–244.PubMedCrossRefGoogle Scholar
  10. Smith P. A., Ashcroft F. M. and Fewtrell C. M. S. (1993). Permeation and gating properties of the L-type calcium channel in mouse pancreatic β-cells. J. Gen. Physiol. 101: 767–797.PubMedCrossRefGoogle Scholar
  11. Valdeolmillos, M., Santos R. M., Contreras D., Soria B. and Rosario LM (1989) Glucose-induced oscillations of intracellular Ca2+ concentration matching bursting electrical activity in single mouse islets of Langerhans. FEBS Lett. 259: 19–23.PubMedCrossRefGoogle Scholar
  12. Valdeolmillos M., Nadal A., Soria B., Garcia-Sancho J. (1993) Fluorescence digital image analysis of glucose-induced [Ca2+]i oscillations in mouse pancreatic islets of Langerhans. Diabetes 42: 1210–1214.PubMedCrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 1997

Authors and Affiliations

  • P. Smith
    • 1
  • P. J. Millard
    • 2
  • C. M. S. Fewtrell
    • 2
  • F. M. Ashcroft
    • 1
  1. 1.University Laboratory of PhysiologyOxfordUK
  2. 2.Department of PharmacologyCornell UniversityIthacaUSA

Personalised recommendations