Advertisement

Pflügers Archiv

, Volume 417, Issue 6, pp 616–621 | Cite as

Bicarbonate permeability of epithelial chloride channels

  • K. Kunzelmann
  • L. Gerlach
  • U. Fröbe
  • R. Greger
Transport Processes Metabolism and Endocrinology; Kidney, Gastrointestinal Tract, and Exocrine Glands

Abstract

Bicarbonate permeability of epithelial chloride channels has been studied using the patch-clamp technique. The experiments were performed in excised insideout oriented membrane patches from three different cultured cell types: (a) HT29 colon carcinoma cell line, (b) T84 colon carcinoma cell line, and (c) respiratory epithelial cells (REC) in primary culture. In all three preparations we observed outwardly rectifying chloride channels with similar conductances with 145 mmol/l NaCl solution in the pipette and in the bath (Clpipette/ Clbath). When Cl was replaced by HCO 3 in the bath (Cl/HCO 3 ) the conductance of the channel at negative clamp voltages was reduced significantly by 40% for HT29 (n=6), 39% for T84 (n=7), and 38% for REC (n=6). Similarly, the zero-current potential (VI=0) was shifted from 0 mV (Cl/Cl) to negative values (Cl/ HCO 3 ) revealing permeability ratios \({{P_{{\text{Cl}}} } \mathord{\left/ {\vphantom {{P_{{\text{Cl}}} } {P_{{\text{H}}_{{\text{CO}}_{\text{3}} } } }}} \right. \kern-\nulldelimiterspace} {P_{{\text{H}}_{{\text{CO}}_{\text{3}} } } }}\) of 2.4±0.1 for HT29 (n=6), 2.0±0.1 for T84 (n=7), and 1.8±0.1 for REC (n=7). With NaHCO3 as the pipette solution and NaCl in the bath, the VI=0 was positive and a \({{P_{{\text{Cl}}} } \mathord{\left/ {\vphantom {{P_{{\text{Cl}}} } {P_{{\text{H}}_{{\text{CO}}_{\text{3}} } } }}} \right. \kern-\nulldelimiterspace} {P_{{\text{H}}_{{\text{CO}}_{\text{3}} } } }}\), value of 2.3±0.1 was determined for HT29 (n=5). Replacement of Cl in the bath by HCO 3 reduced VI=0 to values close to 0 mV. In another series of experiments, the pipette was filled with 145 mmol/l NaCl and the bath contained 35 mmol/l NaCl to which 35 mmol/l NaHCO3 were added. We found that neither the conductance for the inward current nor VI=0 was changed significantly with the additon of NaHCO3 (HT29, n=6). We conclude that the HCO 3 permeability and HCO 3 conductance of these channels is about half of that for Cl.

Key words

Bicarbonate permeability Bicarbonate conductance Cl channels HT29 T84 Respiratory cells Bicarbonate channel 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    Bijman J, Scholte B, De Jonge HR, Hoogeveen AT, Kansen M, Sinaasappel M, van der Kamp AWM (1988) Chloride transport in cystic fibrosis: chloride channel regulation in cultured sweat duct and cultured nasal epithelium. In: Mastella G, Quinton PM (eds) Cellular and molecular basis of cystic fibrosis. San Francisco Press, San FranciscoGoogle Scholar
  2. 2.
    Boucher RC, Larsen EH (1988) Comparison of ion transport by cultured secretory and absorptive canine airway epithelia. Am J Physiol 254:C535-C547Google Scholar
  3. 3.
    Frizzell RA (1987) Cystic fibrosis: a disease of ion channels? Trends Neurosci 10:190–193Google Scholar
  4. 4.
    Frizzell RA, Rechkemmer GR, Shoemaker RL (1986) Altered regulation of airway epithelial cell chloride channels in cystic fibrosis. Science 233:558–560Google Scholar
  5. 5.
    Geck P, Heinz E (1989) Secondary active transport. Kidney Int 36:334–341Google Scholar
  6. 6.
    Gögelein H (1988) Chloride channels in epithelia. Biochim Biophys Acta 947:521–547Google Scholar
  7. 7.
    Gray MA, Greenwell JR, Argent BE (1988) Secretion-regulated chloride channel on the apical plasma membrane of pancreatic duct cells. J Membr Biol 1058:131–142Google Scholar
  8. 8.
    Gray MA, Harris A, Coleman L, Greenwell JR, Argent BE (1989) Two types of chloride channel on duct cells cultured from human fetal pancreas. Am J Physiol 257:C240-C251Google Scholar
  9. 9.
    Greger R, Kunzelmann K (1990) Epithelial chloride channels. In: Young JA, Wong PYD (s) Epithelial secretion of water and electrolytes. Springer, New York, pp 237–247Google Scholar
  10. 10.
    Greger R, Schlatter E (1984) Mechanism of NaCl secretion in rectal gland tubules of spiny dogfish (Squalus acanthias): I. Experiments in isolated in vitro perfused rectal gland tubules. Pflügers Arch 402:63–75Google Scholar
  11. 11.
    Greger R, Schlatter E, Gögelein H (1987) Chloride channels in the luminal membrane of the rectal gland of the dogfish (Squalus acanthias). Properties of the “larger” conductance channel. Pflügers Arch 409:114–121Google Scholar
  12. 12.
    Greger R, Gerlach L, Kunzelmann K (1990) Epithelial chloride channels. Properties and regulation. In: Keelig D, Benham C (eds) Ion transport. Academic Press, London, pp 237–247Google Scholar
  13. 13.
    Halm DR, Rechkemmer GR, Schoumacher RA, Frizzell RA (1988) Apical membrane chloride channels in a colonic cell line activated by secretory agonists. Am J Physiol 254:C505-C511Google Scholar
  14. 14.
    Hayslett JP, Gögelein H, Kunzelmann K, Greger R (1987) Characteristics of apical chloride channels in human colon cells (HT29). Pflügers Arch 410:487–494Google Scholar
  15. 15.
    Kunzelmann K, Unal O, Beck C, Emmrich P, Arndt JH, Greger R (1988) Regulation of ion channels in respiratory cells of cystic fibrosis patients and normal individuals (abstract). Pflügers Arch 412:R10Google Scholar
  16. 16.
    Kunzelmann K, Pavenstädt H, Greger R (1989) Properties and regulation of chloride channels in cystic fibrosis and normal airway cells. Pflügers Arch 415:172–182Google Scholar
  17. 17.
    Novak J, Greger R (1988) Properties of the luminal membrane of isolated perfused rat pancreatic ducts. Pflügers Arch 411:546–553Google Scholar
  18. 18.
    Rohlicek V, Fröbe U, Gögelein H, Greger R (1989) Versatile supplement device with remote control for the control of patch clamp experiments. Pflügers Arch 413:444–446Google Scholar
  19. 19.
    Stetson DL, Beauwens R, Palmisano J, Mitchell PP, Steinmetz PR (1985) A double-membrane model for urinary bicarbonate secretion. Am J Physiol 249:F546-F552Google Scholar
  20. 20.
    Tabcharani JA, Jensen TJ, Riordan JR, Hanrahan JW (1989) Bicarbonate permeability of the outwardly rectifying anion channel. J Membr Biol 112:109–122Google Scholar
  21. 21.
    Wangemann P, Di Stefano A, Wittner M, Englert HC, Lang HJ, Schlatter E, Greger R (1986) Cl-channel blockers in the thick ascending limb of the loop of Henle. Structure activity relationship. Pflügers Arch 407 [Suppl 2]:S128-S141Google Scholar
  22. 22.
    Welsh MJ (1986) An apical-membrane chloride channel in human tracheal epithelium. Science 232:1648–1649Google Scholar
  23. 23.
    Willumsen NJ, Boucher RC (1989) Activation of an apical Cl conductance by Ca2+ ionophores in cystic fibrosis airway epithelia. Am J Physiol 256:C226-C233Google Scholar

Copyright information

© Springer-Verlag 1991

Authors and Affiliations

  • K. Kunzelmann
    • 1
  • L. Gerlach
    • 1
  • U. Fröbe
    • 1
  • R. Greger
    • 1
  1. 1.Physiologisches Institut der Albert-Ludwigs-Universität FreiburgFreiburgFederal Republic of Germany

Personalised recommendations