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Noise analysis of cAMP-stimulated Na current in frog colon

  • Transport Processes, Metabolism and Endocrinology; Kidney, Gastrointestinal Tract, and Exocrine Glands
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Abstract

The effects of oxytocin and cAMP on the electrogenic Na+-transport in the short-circuited epithelium of the frog colon (Rana esculenta, Rana temporaria) were investigated. Oxytocin (100 mU · ml−1) elevated the shortcircuit current (I sc) transiently by 70% whereas cAMP (1 mmol · l−1) elicited a comparable sustained response. The mechanism of the natriferic action of cAMP was studied by analysing current fluctuations through apical Na+-channels induced by amiloride or CDPC (6-chloro-3,5-diaminopyrazine-2-carboxamid). The noise data were used to calculate Na+-channel density (M) and single apical Na+-current (i Na).i Na-Values obtained with amiloride and CDPC were 1.0±0.1 pA (n=5) and 1.1±0.2 pA (n=6) respectively and unaffected by cAMP. On the other hand, cAMP caused a significant increase in M from 0.23±0.08 μm−2 (n=5) to 0.49±0.17 μm−2 (n=5) in the amiloride experiments. In our studies with CDPC we obtained smaller values for M in control (0.12±0.04 μm−2;n=6) as well as during cAMP treatment (0.19±0.06 μm−2;n=6). However, the cAMP-induced increase in M was also significant. We conclude that cAMP stimulates Na+-transport across the frog colon by activating “silent” apical Na+-channels. Thus, the mechanism of regulation of colonic Na-transport in frogs differs considerably from that in other vertebrates as mammals and birds.

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References

  1. Bridges RJ, Rummel W, Wollenberg P (1984) Effects of vasopressin on electrolyte transport across isolated colon from normal and dexamethasone-treated rats. J Physiol 355:11–23

    Google Scholar 

  2. Christensen O, Bindslev N (1982) Fluctuation analysis of short-circuit current in a warm-blooded sodium-retaining epithelium: site current, density, and interaction with triamterene. J Membr Biol 65:19–30

    Google Scholar 

  3. Clauss W, Dürr JE, Skadhauge E, Hörnicke H (1985) Effects of aldosterone and dexamethasone on apical membrane properties and Na-transport of rabbit distal colon in vitro. Pflügers Arch 403:186–192

    Google Scholar 

  4. Clauss W, Dürr JE, Guth D, Skadhauge E (1987) Effects of adrenal steroids on Na-transport in the lower intestine (coprodeum) of the hen. J Membr Biol 96:141–152

    Google Scholar 

  5. Cofré G, Crabbé J (1967) Active sodium transport by the colon of Bufo marinus: Stimulation by aldosterone and antidiuretic hormone. J Physiol 188:177–190

    Google Scholar 

  6. Cuthbert AW (1987) Comparative aspects of electrogenic sodium and electrogenic chloride transport in epithelial tissues. In: Kirsch R, Lahlou B (eds) Comparative physiology of environmental adaptations. Karger, Basel, pp 37–45

    Google Scholar 

  7. De Wolf I, Van Driessche W (1986) Voltage dependent Ba2+ block of K+ channels in apical membrane of frog skin. Am J Physiol 251:C696-C706

    Google Scholar 

  8. Eisenthal R, Cornish-Bowden A (1974) The direct linear plot. A new graphical procedure for estimating enzyme kinetic parameters. Biochem J 139:715–720

    Google Scholar 

  9. Erlij D, Van Driessche W, De Wolf I (1986) Oxytocin stimulates the apical K+ conductance in frog skin. Pflügers Arch 407: 602–606

    Google Scholar 

  10. Frizzell RA, Heintze K (1979) Electrogenic chloride secretion by the mammalian colon. In: Binder H (ed) Mechanisms of intestinal secretion. Liss, New York, pp 101–110

    Google Scholar 

  11. Helman SI, Cox TC, Van Driessche W (1983) Hormonal control of apical membrane Na transport in epithelia. Studies with fluctuation analysis. J Gen Physiol 82:201–220

    Google Scholar 

  12. Krattenmacher R, Clauss W (1988) Electrophysiological analysis of sodium-transport in the colon of the frog (Rana esculenta). Modulation of apical membrane properties by antidiuretic hormone. Pflügers Arch 411:606–612

    Google Scholar 

  13. Lewis SA (1983) Control of Na+ and water absorption across vertebrate “tight” epithelia by ADH and aldosterone. J Exp Biol 106:9–24

    Google Scholar 

  14. Li JH-J, Lindemann B (1983) Competive blocking of epithelial sodium channels by organic cations: The relationship between macroscopic and microscopic inhibition constants. J Membr Biol 76:235–251

    Google Scholar 

  15. Li JH-J, Palmer LG, Edelman IS, Lindemann B (1982) The role of sodium-channel density in the natriferic response of the toad urinary bladder to an antidiuretic hormone. J Membr Biol 64:77–89

    Google Scholar 

  16. Lindemann B (1984) Fluctuation analysis of sodium channels in epithelia. Annu Rev Physiol 46:497–515

    Google Scholar 

  17. Lindemann B, Van Driessche W (1977) Sodium-specific membrane channels of frog skin are pores: Current fluctuations reveal high turnover. Science 195:292–294

    Google Scholar 

  18. Macchia DD, Helman SI (1979) Transepithelial current-voltage relationships of toad urinary bladder and colon. Estimates ofE Na A and shunt resistance. Biophys J 27:371–392

    Google Scholar 

  19. Orloff J, Handler J (1967) The role of adenosine 3′,5′-phosphate in the action of antidiuretic hormone. Am J Med 42:757–768

    Google Scholar 

  20. Palmer LG, Li JH-J, Lindemann B, Edelman IS (1982) Aldosterone control of the density of sodium channels in the toad urinary bladder. J Membr Biol 64:91–102

    Google Scholar 

  21. Reif MC, Troutman SL, Schafer JA (1986) Sodium transport by rat cortical collecting tubule. Effects of vasopressin and desoxycorticosterone. J Clin Invest 77:1291–1298

    Google Scholar 

  22. Stetson DL, Lewis SA, Alles W, Wade JB (1982) Evaluation by capacitance measurements of antidiuretic hormone induced membrane area changes in toad bladder. Biochim Biophys Acta 689:267–274

    Google Scholar 

  23. Thompson L, Baxendale M, Helman SI (1987) Fluctuation analysis of ion transport by frog colon. Fed Proc 4:1269 (Abstract)

    Google Scholar 

  24. Van Driessche W, Erlij D (1983) Noise analysis of inward and outward Na+ currents across the apical border of ouabaintreated frog skin. Pflügers Arch 398:179–188

    Google Scholar 

  25. Van Driessche W, Gullentops K (1982) Conductance fluctuation analysis in epithelia. In: Baker PF (ed) Techniques in the life sciences. Techniques in cellular physiology, P133, County Clave, New York, Elsevier/North-Holland Scientific Publishers Ltd, pp 1–13

    Google Scholar 

  26. Van Driessche W, Lindemann B (1978) Low-noise amplification of voltage and current fluctuations arising in epithelia. Rev Sci Instrum 49:52–57

    Google Scholar 

  27. Van Driessche W, Lindemann B (1979) Concentration-dependence of currents through single sodium-selective pores in frog skin. Nature 282:519–520

    Google Scholar 

  28. Will PC, Cortright RN, DeLisle RC, Douglas JG, Hopfer U (1985) Regulation of amiloride-sensitive electrogenic sodium transport in the rat colon by steroid hormones. Am J Physiol 248:G124-G132

    Google Scholar 

  29. Wills NK, Zweifach A (1987) Recent advances in the characterization of epithelial ionic channels. Biochim Biophys Acta 906:1–31

    Google Scholar 

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Krattenmacher, R., Fischer, H., van Driessche, W. et al. Noise analysis of cAMP-stimulated Na current in frog colon. Pflugers Arch. 412, 568–573 (1988). https://doi.org/10.1007/BF00583756

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  • DOI: https://doi.org/10.1007/BF00583756

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