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Expression of a rapid, low-voltage threshold K current in insulin-secreting cells is dependent on intracellular calcium buffering

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Summary

Depolarization-activated outward currents ranging in amplitude from 100–1000 pA were studied in cultured, insulinsecreting HIT cells and mouse B-cells using the whole-cell patch clamp. Outward current was identified as a K current since it was blocked by K channel blockers and its tail current reversed nearE K. The K currents of HIT cells dialyzed with internal solutions containing 0.1–10mm EGTA with no added calcium (Ca), or 10mm EGTA with 2mm added Ca, activated rapidly with depolarization. However, the stronger Ca buffer BAPTA (5mm; no added Ca) blocked the rapidly activating current to reveal an underlying more slowly activating K current. With intracellular EGTA, application of the Ca channel blocker cadmium mimicked the effect of intracellular BAPTA. These data suggest that the rapid K current was mediated by low-voltage threshold, Ca-activated K channels while the slower K current was mediated by high threshold delayed rectifier K channels. Mouse B-cells also had both K current components. Dialyzing these cells with either BAPTA (5mm, no added Ca) or high EGTA (10mm with 2mm Ca) blocked the rapid Ca-activated K current observed when cells were filled with 0.1 to 1mm EGTA. It is concluded that the extent of Ca-activated K current activation in either HIT or adult mouse B-cells depends on the degree of intracellular Ca buffering.

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References

  • Adams, P.R., Brown, D.A., Constanti, A. 1982a,. M-currents and other potassium currents in bullfrog sympathetic neurones.J. Physiol. (London) 330:537–572

    Google Scholar 

  • Adams, P.R., Brown, D.A., Constanti, A., Clark, R.B., Satin, L. 1985. Calcium-activated potassium channels in bullfrog sympathetic ganglion cells.In: Calcium In Biological Systems. R. Rubin, G. Weiss, and J. Putney, Jr., editors. pp. 181–191. Plenum, New York

    Google Scholar 

  • Adams, P.R., Constanti, A., Brown, D.A.., Clark, R.B. 1982b. Intracellular Ca2+ activates a fast voltage-sensitive K+ current in vertebrate sympathetic neuronesNature (London) 296:746–749

    Google Scholar 

  • Ashcroft, F.M., Harrison, D.E., Ashcroft, S.J.H. 1984. Glucose induces closure of single potassium channels in isolated rat pancreatic β-cells.Nature (London) 312:446–448

    Google Scholar 

  • Atwater, I., Ribalet, B., Rojas, E. 1979. Mouse pancreatic β-cells: Tetraethylammonium blockage of the potassium permeability increased induced by depolarization.J. Physiol. (London) 288:561–574

    Google Scholar 

  • Bangham, J.A., Smith, P.A., Croghan, P.C. 1986. Modelling the β-cell, electrical activity.In: Biophysics of the Pancreatic B-cell. I. Atwater, E. Rojas, and B. Soria, editors. pp. 265–278. Plenum, New York.

    Google Scholar 

  • Bozem, M., Henquin, J.C. 1989. Glucose modulation of spike activity independently from changes in slow waves of membrane potential in mouse β-cells.Pfluegers Arch. 413:147–159

    Google Scholar 

  • Brehm, P., Dunlap, K., Eckert, R. 1978. Calcium-dependent repolarization in Paramecium.J. Physiol. (London) 274:639–654

    Google Scholar 

  • Carbone, E., Lux, H.D. 1987. Kinetics and selectivity of a lowthreshold voltage-activated calcium current in rat sensory neurones.J. Physiol. (London) 366:547–570

    Google Scholar 

  • Cook, D.L.., Hales C.N. 1984. Intracellular ATP directly blocks K channels in pancreatic B-cells.Nature (London) 311:271–273

    Google Scholar 

  • Cook, D.L., Ikeuchi, M. 1989. Tolbutamide mimics the effect of glucose on B-cell electrical activity: ATP-sensitive K channels may be a common pathway for both stimuli.Diabetes 38:416–421

    Google Scholar 

  • Cook, D.L., Ikeuchi, M., Fujimoto, W.Y. 1984. Lowering of pH i inhibits Ca-activated K channels in pancreatic B-cells.Nature (London) 311:269–271.

    Google Scholar 

  • Eckert, R. Chad, R. 1984. Inactivation of Ca channels.Prog. Biophys. Mol. Biol. 44:215–267

    Google Scholar 

  • Einot, T., Gabriel, K.R. 1975. A study of the powers of several methods of multiple comparisons.J. Am. Statist. Assoc. 70:574–583

    Google Scholar 

  • Fabiato, A., Fabiato, F. 1979. Calculator programs for computing the composition of the solutions containing multiple metals and ligands used for experiments in skinned muscle cells.J. Physiol. (Paris) 75:463–505

    Google Scholar 

  • Findlay, I.., Dunne, M.J. 1986. Voltage-activated Ca and K currents in an insulin-secreting cell line (RINm5F).In: Biophysics of the Pancreatic B-cell. I. Atwater, E. Rojas, and B. Soria, editors. pp. 177–187. Plenum, New York

    Google Scholar 

  • Findlay, I., Dunne, M.J., Petersen, O.H.. 1985a. ATP-sensitive inward rectifier and voltage-and calcium-activated K channels in cultured pancreatic islet cells.J. Membrane Biol. 88:165–172

    Google Scholar 

  • Findlay, I., Dunne, M.J., Petersen, O.H. 1985b. High-conductance K channels in pancreatic islet cells can be activated and inactivated by internal calcium.J. Membrane Biol. 83:169–175

    Google Scholar 

  • Findlay, I., Dunne, M.J., Ullrich S., Wollheim, C.B., Petersen, O.H. 1985c. Quinine inhibits Ca-independent K channels whereas tetraethylammonium inhibits Ca-activated K channels in insulin-secreting cells.FEBS Lett. 185:4–8

    Google Scholar 

  • Hagiwara, S., Nakajima, S. 1966. Effects of the intracellular Ca ion concentration upon the excitability of the muscle fiber membrane of a barnacle.J. Gen. Physiol. 49:807–818

    Google Scholar 

  • Hamill, O.P., Marty, A., Neher, E., Sakmann, B., Sigworth, F.J. 1981. Improved patch clamp techniques for high-resolution current recording from cells and cell-free membrane patches.Pfluegers Arch. 391:85–100

    Google Scholar 

  • Hille, B. 1984. Ionic Channels of Excitable Cells. Sinauer and Associates, Sunderland, MA

    Google Scholar 

  • Hiriart, M., Matteson, D.R. 1988. Na channels and two types of Ca channels in rat pancreatic B cells identified with the reverse hemolytic plaque assay.J. Gen. Physiol. 91:617–639

    Google Scholar 

  • Hopkins, W.F., Satin, L.S., Cook, D.L. 1989. Calcium and depolarization-dependent Ca current inactivation in cultured mouse B-cells.Diabetes 38:96A

    Google Scholar 

  • Lancaster, B., Nicoll, R.A. 1987. Properties of two calcium-activated hyperpolarizations in rat hippocampal neurons.J. Physiol. (London) 389:187–203

    Google Scholar 

  • Marty, A., Neher, E. 1985. Potassium channels in cultured bovine adrenal chromaffin cells.J. Physiol. (London) 367:117–141

    Google Scholar 

  • Misler, S., Falke, L., Gillis, K., Hammond, A., Tabcharani, J. 1988. Voltage-gated single K and Ca channel currents in pancreatic islet B-cells.J. Gen. Physiol. 92:7a

    Google Scholar 

  • Misler, S., Falke, L.C.., Gillis, K., McDaniel, M.L. 1986. A metabolite-regulated potassium channel in rat pancreatic B cells.Proc. Natl. Acad Sci. USA 83:7119–7123

    Google Scholar 

  • Mitra, R., Morad, M. 1985. Ca and Ca-activated K currents in mammalian gastric smooth muscle cells.Science 229:269–272

    Google Scholar 

  • Plant, T.D. 1988 Properties and calcium-dependent inactivation of calcium current in cultured mouse pancreatic β-cells.J. Physiol. (London) 404:731–747

    Google Scholar 

  • Ribalet, B., Beigelman, P.M. 1980. Calcium action potentials and potassium permeability activation in pancreatic β-cells.Am. J. Physiol. 239:C124-C133

    Google Scholar 

  • Rorsman, P., Trube, G. 1985. Glucose dependent K-channels in pancreatic β-cells are regulated by intracellular ATP.Pfluegers Arch. 405:305–309

    Google Scholar 

  • Rorsman, P., Trube, G. 1986. Calcium and delayed potassium currents in mouse pancreatic β-cells under voltage-clamp conditions.J. Physiol. (London) 374:531–550

    Google Scholar 

  • Rorsman, P., Trube, G., Ohno-Shosaku, T.. 1986. Opposite effects of tolbutamide and diazoxide on the ATP-dependent K channel in mouse pancreatic B-cells.Pfluegers Arch. 407:493–499

    Google Scholar 

  • Santerre, R.F., Cook, R.A., Crisel, R.M.S.D., Sharp, J.D., Schmidt, R.J., Williams, D.C., Wilson, C.P. 1981. Insulin synthesis in a clonal cell line of simian virus 40-transformed hamster pancreatic beta cells.Proc. Natl. Acad. Sci. USA 78:4339–4343

    Google Scholar 

  • Satin, L.S. 1989. Experession of a rapid, low-threshold Ca-activated K current depends on the extent of intracellular Ca buffering in HIT cells.Diabetes 38:96A

    Google Scholar 

  • Satin, L.S., Cook, D.L. 1988. Evidence for two Ca currents in insulin-secreting cells.Pfluegers Arch. 411:401–409

    Google Scholar 

  • Satin, L.S., Cook, D.L. 1989. Calcium current inactivation in insulin-secreting cells is mediated by calcium influx and membrane depolarization.Pfluegers Arch. 414:1–10

    Google Scholar 

  • Thomas, M.V. 1982 Techniques in Calcium Research. Academic, New York

    Google Scholar 

  • Trube, G., Rorsman, P. 1986. Calcium and potassium currents recorded from pancreatic β-cells under voltage-clamp control.In: Biophysics of the Pancreatic B-cell. I. Atwater, E. Rojas, and B. Soria, editors. pp. 167–175. Plenum, New York

    Google Scholar 

  • Tsien, R.Y. 1980 New calcium indicators with high selectivity against magnesium and protons: Design, synthesis and properties of prototype structures.Biochemistry 19:2396–2404

    Google Scholar 

  • Zunkler, B.J., Trube, G.., Ohno-Shosaku, T. 1988. Forskolin-induced block of delayed rectifying K channels in pancreatic β-cells is not mediated by cAMP.Pfluegers Arch. 411:613–619

    Google Scholar 

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Authors and Affiliations

  1. Departments of Physiology and Biophysics, University of Washington School of Medicine, 98108, Seattle, Washington

    Leslie S. Satin, William F. Hopkins, Sahba Fatherazi & Daniel L. Cook

  2. Department of Medicine, University of Washington School of Medicine, 98108, Seattle, Washington

    Leslie S. Satin, William F. Hopkins, Sahba Fatherazi & Daniel L. Cook

  3. Seattle Veterans Administration Medical Center, 98108, Seattle, Washington

    Leslie S. Satin, William F. Hopkins, Sahba Fatherazi & Daniel L. Cook

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  1. Leslie S. Satin
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  2. William F. Hopkins
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  3. Sahba Fatherazi
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  4. Daniel L. Cook
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Satin, L.S., Hopkins, W.F., Fatherazi, S. et al. Expression of a rapid, low-voltage threshold K current in insulin-secreting cells is dependent on intracellular calcium buffering. J. Membrain Biol. 112, 213–222 (1989). https://doi.org/10.1007/BF01870952

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  • DOI: https://doi.org/10.1007/BF01870952

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