Contribution of Isotope Flux Studies to Understanding the Mechanism of the β-Cell Membrane
The membrane potential of the animal cell membrane is determined principally by the diffusion of ions. Such a diffusion potential is determined by the concentrations of the diffusing (electrogenic) ions on either side of the membrane and by the permeability of the membrane to these ions. In the resting membrane, the permeability of the K+ ion is usually the dominant factor and depolarization of the membrane is caused by a reduction in K+ permeability and/or an increase in the permeability of other ions such as Na+ and/or Ca2+. These changes in membrane potential play a key role in the function of various cell types, including the pancreatic β-cell, where they seem to initiate processes leading ultimately to insulin release.
KeywordsMembrane Potential Insulin Release Permeability Coefficient Efflux Rate Mouse Islet
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- 3.L. Beauge & V.L. Lew, Passive fluxes of sodium and potassium across red cell membranes, in: “Membrane Transport in Red Cells”, J.C. Ellory and V.L. Lew, eds., Academic Press, London, pp 39 (1977).Google Scholar
- 7.C.M. Dawson, I. Atwater and E. Rojas, The response of the pancreatic β-cell membrane potential to potassium-induced calcium influx in the presence of glucose, Quarterly J. Exp. Physiol.69:819 (1984).Google Scholar
- 8.C.M. Dawson, P.C. Croghan, I. Atwater and E. Rojas, Estimation of potassium permeability in mouse islets of Langerhans, Biomed. Res.4:389 (1983).Google Scholar
- 9.C.M. Dawson, P.C. Croghan, A.M. Scott and J.A. Bangham, Direct comparison of K+ and Rb+ efflux in normal mouse islets, Diabetologia 27:267A (1984).Google Scholar
- 10.C.M. Dawson, P.C. Croghan, A.M. Scott and J.A. Bangham, Potassium and rubidium permeability and potassium conductance of the β-cell membrane in mouse islets of Langerhans, Quarterly J. Exp. Physiol. 71:205 (1986).Google Scholar
- 16.R. Ferrer, I. Atwater, E.M. Omer, A.A. Goncalves, P.C. Croghan and E. Rojas, Electrophysiological evidence for the inhibition of potassium permeability in pancreatic β-cells by glibenclamide, Quarterly J. Exp. Physiol.69:831 (1984).Google Scholar
- 20.J.C. Henquin, The potassium permeability of pancreatic islet cells: mechanisms of control and influence on insulin release, Hormone and Metabolic Res. Supp. Series 10:66 (1980).Google Scholar
- 24.T.J.C. Jacob, J.A. Bangham and G. Duncan, Characterization of a cation channel on the apical surface of the frog lens epithelium, Quarterly J. Exp. Physiol. 70:403 (1985).Google Scholar
- 32.H.H. Ussing, Active transport of inorganic ions, Symposia Soc. Exp. Biol.8:407 (1954).Google Scholar