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Pflügers Archiv

, Volume 431, Issue 1, pp 52–65 | Cite as

Maxi K+ channels in the basolateral membrane of the exocrine frog skin gland regulated by intracellular calcium and pH

  • Henning K. Andersen
  • Valerie Urbach
  • Emmy Van Kerkhove
  • Ena Prosser
  • Brian J. Harvey
Original Article Transport Processes, Metabolism and Endocrinology; Kidney, Gastrointestinal Tract and Exorcrine Glands

Abstract

With the single-channel patch-clamp technique we have identified Ca2+-sensitive, high-conductance (maxi) K+ channels in the basolateral membrane (BLM) of exocrine gland cells in frog skin. Under resting conditions, maxi K+ channels were normally quiescent, but they were activated by muscarinic agonists or by high serosal K+. In excised inside-out patches and with symmetrical 140 mmol/l K+, single-channel conductance was 200 pS and the channel exhibited a high selectivity for K+ over Na+. Depolarization of the BLM increased maxi K+ channel activity. Increasing cytosolic free Ca2+ (by addition of 100 nmol/l thapsigargin to the bathing solution of cell-attached patches also increased channel activity, whereas thapsigargin had no effect when added to excised inside-out patches. An increase in cytosolic free Ca2+ directly activated channel activity in a voltage-dependent manner. Maxi K+ channel activity was sensitive to changes in intracellular pH, with maximal activity at pH 7.4 and decreasing activities following acidification and alkalinization. Maxi K+ channel outward current was reversibly blocked by micromolar concentrations of Ba2+ from the cytosolic and extracellular site, and was irreversibly blocked by micromolar concentrations of charybdotoxin and kaliotoxin from the extracellular site in outside-out patches.

Key words

Calcium Frog skin glands Maxi K+ channel Patch clamp pH Thapsigargin 

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References

  1. 1.
    Brown PD, Loo DDF, Wright EM (1988) Ca2+ activated K+ channels in the apical membrane of necturus choroid plexus. J Membr Biol 105:207–219Google Scholar
  2. 2.
    Burgen ASV (1956) The secretion of potassium in saliva. J Physiol (Lond) 132:20–39Google Scholar
  3. 3.
    Chang D, Hsieh PS, Dawson DC (1988) Calcium: a program in BASIC for calculating the composition of solutions with specified free concentrations of calcium, magnesium and other divalent cations. Comp Biol Med 18:351–366Google Scholar
  4. 4.
    Christensen O, Zeuthen T (1987) Maxi K+ channels in leaky epithelia are regulated by intracellular Ca2+, pH and membrane potential. Pflügers Arch 408:249–259Google Scholar
  5. 5.
    Coppello J, Segal Y, Reuss L (1991) Cytosolic pH regulates maxi K+ channels in Necturus gall bladder epithelial cells. J Physiol (Lond) 434:577–590Google Scholar
  6. 6.
    Cornejo M, Guggino SE, Guggino WB (1990) Ca2+-activated K+ channels from cultured renal meddulla thick ascending limb cells: Effects of pH. J Membr Biol 110:49–55Google Scholar
  7. 7.
    Crest M, Jacquet G, Gola M, Zerrouk H, Benslimane A, Rochat H, Mansuelle P, Eauclaire MFM (1992) Kaliotoxin, a novel peptidyl inhibitor of neuronal BK-type Ca2+-activated channels characterized from Androctonus mauretanicus mauretanicus venom. J Biol Chem 267:1640–1647Google Scholar
  8. 8.
    Findlay I, Petersen OH (1985) Acetylcholine stimulates a Ca2+ dependent Cl conductance in mouse lacrimal acinar cells. Pflügers Arch 403:328–330Google Scholar
  9. 9.
    Gimenez-Callego G, Navia MA, Reuben JP, Katz GM, Kaczorowski GJ, Garcia ML (1988) Purification, sequence, and model structure of charybdotoxin, a potent selective inhibitor of calcium-activated potassium channels. Proc Natl Acad Sci USA 85:3329–3333Google Scholar
  10. 10.
    Gray MA, Greenwell JR, Garton AJ, Argent BE (1990) Regulation of maxi-K+ channels on pancreatic duct cells by cyclic AMP-dependent phosphorylation. J Membr Biol 115: 203–215Google Scholar
  11. 11.
    Groschner K, Silberberg SD, Gelband GH, van Breemen C (1991) Ca2+-activated K+ channels in airway smooth muscle are inhibited by cytoplasmic adenosine triphosphate. Pflügers Arch 417:517–522Google Scholar
  12. 12.
    Hamill OP, Marty A, Neher E, Sakmann B, Sigworth FJ (1981) Improved patch clamp techniques for high resolution current recording from cells and cell free membrane patches. Pflügers Arch 391:85–100Google Scholar
  13. 13.
    Hazama A, Okada Y (1990) Biphasic rises in cytosolic free Ca2+ in association with activation of K+ and Cl conductance during the regulatory decrease in cultured human epithelial cells. Pflügers Arch 416:710–714Google Scholar
  14. 14.
    Henderson RM, Cuthbert AW (1991) An outward rectifying potassium channel in primary cultures of sweat glands from cystic fibrosis subjects. Biochim Biophys Acta 1097:219–223Google Scholar
  15. 15.
    Henderson RM, Cuthbert AW (1991) A high conductance Ca2+ activated K+ channel in cultured human eccrine sweat gland cells. Pflügers Arch 418:271–275Google Scholar
  16. 16.
    Hille B (1984) Ionic channels of excitable membranes, pp 274–275 Sinauer, Sunderland, Mass., pp. 274–275Google Scholar
  17. 17.
    Hirsch J, Leipziger U, Fröbe U, Schlatter E (1993) Regulation and possible role of the Ca2+ dependent K+ channel of the cortical collecting ducts of the rat. Pflügers Arch 422: 492–498Google Scholar
  18. 18.
    Hunter M, Kawahara K, Giebisch G (1988) Calcium-activated epithelial potassium channels. Miner Electrolyte Metab 14: 48–57Google Scholar
  19. 19.
    Klærke DA, Wiener H, Zeuthen T, Jørgensen PL (1993) Ca2+ activation and pH dependence of a maxi K+ channel from rabbit distal colon epithelium. J Membr Biol 136:9–21Google Scholar
  20. 20.
    Kume H, Tagagi K, Satake T, Tokuno H, Tomita T (1990) Effects of intracellular pH on calcium activated potassium channels in rabbit tracheal smooth muscle. J Physiol (Lond) 424: 445–457Google Scholar
  21. 21.
    Latorre R, Miller C (1983) Conduction and selectivity in potassium channels. J Membr Biol 71:11–35Google Scholar
  22. 22.
    Loo DDF, Kaunitz JD (1989) Ca2+ and cAMP activate K+-channels in the basolateral membrane of crypt cells isolated from rabbit distal colon. J Membr Biol 110:19–28Google Scholar
  23. 23.
    Mancilla E, Rojas E (1990) Quinine blocks the high conductance, calcium-activated potassium channel in rat pancreatic beta-cells. FEBS Lett 260:105–108Google Scholar
  24. 24.
    Martinez JR, Cassity N (1986) 36Cl fluxes in dispersed rat submandibular acini: effects of Ca2+ omission and the ionophore A23187. Pflügers Arch 290:124–133Google Scholar
  25. 25.
    Merritt JE, Rink TJ (1987) Rapid increases in cytosolic free calcium in response to muscarinic stimulation of rat parotid acinar cells. J Biol Chem 262:4958–4960Google Scholar
  26. 26.
    Nauntofte B (1992) Regulation of electrolyte and fluid secretion in salivary acinar cells. Am J Physiol 263:G823-G837Google Scholar
  27. 27.
    Nauntofte B, Poulsen JH (1986) Effects of Ca2+ and furosemide on Cl transport and O2 uptake in rat parotid acini. Am J Physiol 251:C175-C185Google Scholar
  28. 28.
    Nielsen R (1990) Isotonic secretion via frog skin glands in vitro. Water secretion is coupled to the secretion of sodium ions. Acta Physiol Scand 139:211–221Google Scholar
  29. 29.
    Petersen OH (1992) Stimulus-secretion coupling: cytoplasmic calcium signals and the control of ion channels in exocrine acinar cells. J Physiol (Lond) 448:1–51Google Scholar
  30. 30.
    Rusko J, Tanzi F, van Breemen C, Adams DJ (1992) Calciumactivated potassium channels in native endothelial cells from rabbit aorta: conductance, Ca2+ sensitivity and block. J Physiol (Lond) 455:601–621Google Scholar
  31. 31.
    Suva P, Stoff J, Field M, Fine L, Forrest JN, Epstein FH (1977) Mechanism of active chloride secretion by shark rectal gland: role of Na-K ATPase in chloride transport. Am J Physiol 233:F298-F306Google Scholar
  32. 32.
    Soltoff SP, McMillian MK, Cantley LC, Cragoe JR, Talamo B (1989) Effects of muscarinic, alpha adrenergic, and substance P agonists and ionomycin on ion transport mechanisms in rat parotid acinar cells. The dependence of ion transport on intracellular calcium. J Gen Physiol 93:285–319Google Scholar
  33. 33.
    Thastrup O, Dawson AP, Scharff O, Foder B, Cullen PJ, Drøbak BK, Bjerrum PJ, Christensen SB, Hanley MR (1989) Thapsigargin, a novel molecular probe for studying intracellular calcium release and storage. Agents Actions 27:17–23Google Scholar
  34. 34.
    Ussing HH, Eskesen K (1989) Mechanism of isotonic water transport in glands. Acta Physiol Scand 136:443–454Google Scholar
  35. 35.
    Whittemore ER, Korotzer AR, Etebari A, Cotman CW (1993) Carbachol increases intracellular free calcium in cultured rat microglia. Brain Res 621:59–64Google Scholar

Copyright information

© Springer-Verlag 1995

Authors and Affiliations

  • Henning K. Andersen
    • 1
  • Valerie Urbach
    • 2
  • Emmy Van Kerkhove
    • 3
  • Ena Prosser
    • 2
  • Brian J. Harvey
    • 2
  1. 1.Zoophysiological LaboratoryAugust Krogh InstituteCopenhagen ØDenmark
  2. 2.Cellular Physiology Research Unit, CPRU, Department of PhysiologyUniversity College CorkCorkIreland
  3. 3.LUC, Dept. MBW-FysiologieLimburgs Universitair CentrumDiepenbechBelgium

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