The Journal of Membrane Biology

, Volume 131, Issue 2, pp 143–149 | Cite as

A patch-clamp study of the ionic selectivity of the large conductance, ca-activated chloride channel in muscle vesicles prepared fromAscaris suum

  • D. M. Dixon
  • M. Valkanov
  • R. J. Martin


Plasma membrane vesicles prepared from the bag re gion of the somatic muscle cell of the parasiteAscaris suum contain a large conductance, voltage-sensitive, calcium-activated chloride channel. The ability of this channel to conduct a variety of anions has been investigated using the patch-clamp technique on isolated inside-out patches of muscle membrane. Symmetrical Cl solutions (140 mm) produced single-channel I/V plots with reversal potentials of 0 mV, substitution of bath Cl by 140 mM NO3, Br and I caused depolarizing shifts in the reversal potentials. Replacement of the internal Cl by F (140 mM) caused a large hyperpolarizing shift in the reversal potential. The channel dis played a permeability sequence of I > Br = NO3> Cl > F which differed from the corresponding conductance sequence Cl > NO3 = Br = I > F. The ionic environment within the channel pore has been investigated using Reuter and Stevens (1980) plots to describe the selectivity and “fluidity” of the channel pore. In addition, the approach of Wright and Diamond (1977) was employed to estimate the number of cationic binding sites within the channel pore. The channel is relatively fluid but the number of cationic binding sites varies inversely with the ionic radius of the anion from 2.15 for F to 0.89 for the large planar anion NO3

Key Words

Ascaris suum chloride channels calcium anion channel ionic permeability 


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  1. Borman, J., Hamill, O.P., Sakmann, B. 1987. Mechanism of anion permeation through channels gated by glycine and γ aminobutyric acid in mouse cultured spinal neurons.J. Phys iol. 385:243–286Google Scholar
  2. Brading, A.F., Caldwell, P.C. 1971. The resting membrane poten tial of somatic muscle cells ofAscaris lumbricoides.J. Phys iol. 27:605–624Google Scholar
  3. Buckingham, A.D. 1957. A theory of ion-solvent interaction.Disc. of the Faraday Soc. 24:151–157CrossRefGoogle Scholar
  4. Caldwell, P.C., Ellory, J.C. 1968. Ion movements in somatic muscle cells ofAscaris lumbricoides.J. Physiol. 197:75–76PGoogle Scholar
  5. Del Castillo, J., DeMellow, W.C., Morales, T. 1964. Influence of some ions on the membrane potential ofAscaris muscle.J. Gen. Physiol. 48:129–140CrossRefGoogle Scholar
  6. Eisenman, G. 1961. On elementary atomic origin of equilibrium ionic specificity. In: Symposium on Membrane Transport and Metabolism. A. Kleinzeller and A. Kotyk, editors, pp. 163–179. Academic, New YorkGoogle Scholar
  7. Eisenman, G. 1962. Cation selective glass electrodes and their mode of operation.Biophys. J. 2:259–323PubMedCrossRefGoogle Scholar
  8. Eisenman, G., Horn, R. 1983. Ionic selectivity revisited: the role of kinetic and equilibrium processes in ion permeation through channels.J. Membrane Biol. 76:197–225CrossRefGoogle Scholar
  9. Evans, M.G., Marty, A. 1986. Calcium-dependent chloride cur rents in isolated cells from rat lacrimal glands.J. Physiol. 378:437–460PubMedGoogle Scholar
  10. Franciolini, F., Nonner, W. 1987. Anion and cation permeability of a chloride channel in rat hippocampal neurons.J. Gen. Physiol. 90:453–478PubMedCrossRefGoogle Scholar
  11. Goldman, D.E. 1943. Potential impedence and rectification in membranes.J. Gen. Physiol. 27:37–60CrossRefGoogle Scholar
  12. Grey, P.T.A., Bevan, S., Ritchie, J.M. 1984. High conductance anion-selective channels in rat cultivated Schwann cells.Proc. R. Soc. London B. 221:395–409Google Scholar
  13. Hobson, A.D., Stephenson, W., Eden, A. 1952. Studies on the physiology ofAscaris lumbricoides. 2. The inorganic composi tion of the body fluid in relation to that of the external environ ment.J. Exp. Biol. 29:22–29Google Scholar
  14. Hodgkin, A.L., Katz, B. 1949. The effect of sodium ions on the electrical activity of the giant axion of the squid.J. Physiol. 108:37–77Google Scholar
  15. Jarman, M. 1959. Electric activity in muscle cells ofAscaris muscle.Nature 184:1244PubMedCrossRefGoogle Scholar
  16. Martin, R.J. 1980. The effect of GABA on the input conductance and membrane potential ofAscaris muscle.Br. J. Pharmacol. 71:99–106PubMedGoogle Scholar
  17. Martin, R.J. 1985. GABA and piperazine-activated single channel currents fromA. suum.J. Physiol. 354:46PGoogle Scholar
  18. Martin, R.J., Pennington, A.J. 1989. A patch-clamp study of dihydroavermectin onAscaris muscle.Br. J. Pharmacol. 98:747–756PubMedGoogle Scholar
  19. Marty, A., Tan, Y.P., Trautmann, A. 1984. Three types of calci um-dependent channels in rat lacrimal glands.J. Physiol. 377:293–325Google Scholar
  20. Pauling, L. 1960. The Nature of the Chemical Bond. pp. 283–284. Cornell University, New YorkGoogle Scholar
  21. Reuter, H. Stevens, CF. 1980. Ion conductance and ion selectiv ity of potassium channels in snail neurones.J. Membrane Biol. 57:103–118CrossRefGoogle Scholar
  22. Rheinallt Parri, H., Holden-Dye, L., Walker, R.J. 1991. Studies on the ionic selectivity of the GABA-operated chloride on the somatic muscle bag cells of the parasitic nematodeAscaris suum.Exp. Physiol. 76:597–606Google Scholar
  23. Rosenbluth, J. 1965a. Ultrastructural organisation of obliquely striated muscle fibres inAscaris lumbricoides.J. Cell Biol. 25:494–515CrossRefGoogle Scholar
  24. Rosenbluth, J. 1965e. Ultrastructure of somatic muscle cells inAscaris lumbricoides. II. Intermuscular junctions, neuromuscular junctions, and glycogen stores.Cell Biol. 26:579–591CrossRefGoogle Scholar
  25. Rosenbluth, J. 1967. Obliquely striated muscle. III. Contraction mechanismof Ascaris body muscle.J. Cell Biol. 34:15–33PubMedCrossRefGoogle Scholar
  26. Thorn, P., Martin, R.J. 1987. A high conductance calcium-depen dent chloride channel inA. suum muscle.J. Exp. Physiol. 72:31–49Google Scholar
  27. Wright, E.M., Diamond, J.M. 1977. Anion selectivity in biologi cal systems.Physiol. Rev. 57:109–156PubMedGoogle Scholar
  28. Young, G.P.H., Young, J.D.E., Destipande, A.K., Goldstein, M., Koide, S.S., Cohn, Z.A. 1984. A Ca2+-activated channel fromXenopus laevis oocyte membranes reconstituted into planar bilayers.Proc. Natl. Ac ad. Sci. USA 81:5155–5159CrossRefGoogle Scholar

Copyright information

© Springer-Verlag New York Inc. 1993

Authors and Affiliations

  • D. M. Dixon
    • 1
  • M. Valkanov
    • 1
    • 2
  • R. J. Martin
    • 1
  1. 1.Department of Pre-Clinical Veterinary Sciences, R.(D).S.V.S.University of Edinburgh
  2. 2.Central Laboratory of BiophysicsBulgarian Academy of SciencesSofia

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