Skip to main content
NCBI home page
Proceedings of the National Academy of Sciences of the United States of America logoLink to Proceedings of the National Academy of Sciences of the United States of America
. 1978 Apr;75(4):1703–1707. doi: 10.1073/pnas.75.4.1703

Acetylcholine-receptor-mediated ion flux in electroplax membrane microsacs (vesicles): Change in mechanism produced by asymmetrical distribution of sodium and potassium ions

George P Hess 1, Stanley Lipkowitz 1, Gary E Struve 1
PMCID: PMC392407  PMID: 273901

Abstract

The kinetics of acetylcholine-receptor-mediated efflux of inorganic ions from electroplax microsacs of Electrophorus electricus in the presence of varying alkali metal ion concentrations on both sides of the membrane have been investigated. The efflux, a monophasic process when the ion distribution is symmetrical (the same concentrations and types of ions on both sides of the membrane), becomes a biphasic process, consisting of a very rapid initial release of ions followed by a slower first-order process, under conditions that resemble the physiological state of the neural membrane (potassium ions inside the microsacs and sodium ions on the outside). The initial phase of the efflux discriminates between calcium and sodium ions and is inhibited by potassium ions in the external solution. The rate constant associated with this phase is at least 40 times larger than the rate constant associated with the slower efflux. Both phases depend on the concentration of acetylcholine or carbamoylcholine, and are inhibited by receptor inhibitors (d-tubocurarine and α-bungarotoxin).

A simple model is proposed which relates the kinetics of the flux to ligand-induced conformational changes in the receptor. We also indicate the relationship between the biphasic kinetics of the flux observed in microsacs to “desensitization,” the phenomenon in which, on addition of acetylcholine, the transmembrane voltage of muscle and nerve cells first increases and then decreases to its resting value within a few seconds.

Keywords: asymmetrical physiological distribution of ions, ion flux mechanism, excitability, “desensitization”

Full text

PDF
1703

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Anderson C. R., Stevens C. F. Voltage clamp analysis of acetylcholine produced end-plate current fluctuations at frog neuromuscular junction. J Physiol. 1973 Dec;235(3):655–691. doi: 10.1113/jphysiol.1973.sp010410. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Barrantes F. J. Intrinsic fluorescence of the membrane-bound acetylcholine receptor: its quenching by suberyldicholine. Biochem Biophys Res Commun. 1976 Sep 20;72(2):479–488. doi: 10.1016/s0006-291x(76)80067-8. [DOI] [PubMed] [Google Scholar]
  3. Bonner R., Barrantes F. J., Jovin T. M. Kinetics of agonist-induced intrinsic fluorescence changes in membrane-bound acetylcholine receptor. Nature. 1976 Sep 30;263(5576):429–431. doi: 10.1038/263429a0. [DOI] [PubMed] [Google Scholar]
  4. Bulger J. E., Fu J. L., Hindy E. F., Silberstein R. L., Hess G. P. Allosteric interactions between the membrane-bound acetylcholine receptor and chemical mediators. Kinetic studies. Biochemistry. 1977 Feb 22;16(4):684–692. doi: 10.1021/bi00623a020. [DOI] [PubMed] [Google Scholar]
  5. Changeux J. P., Benedetti L., Bourgeois J. P., Brisson A., Cartaud J., Devaux P., Grünhagen H., Moreau M., Popot J. L., Sobel A. Some structural properties of the cholinergic receptor protein in its membrane environmental relevant to its function as a pharmacological receptor. Cold Spring Harb Symp Quant Biol. 1976;40:211–230. doi: 10.1101/sqb.1976.040.01.023. [DOI] [PubMed] [Google Scholar]
  6. Del Castillo J., Webb G. D. Rapid desensitization of acetylcholine receptors of eel electroplaques following iontophoretic application of agonist compounds. J Physiol. 1977 Sep;270(2):271–282. doi: 10.1113/jphysiol.1977.sp011951. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. ELLMAN G. L., COURTNEY K. D., ANDRES V., Jr, FEATHER-STONE R. M. A new and rapid colorimetric determination of acetylcholinesterase activity. Biochem Pharmacol. 1961 Jul;7:88–95. doi: 10.1016/0006-2952(61)90145-9. [DOI] [PubMed] [Google Scholar]
  8. Eytan G. D., Carroll R. C., Schatz G., Racker E. Arrangement of the subunits in solubilized and membrane-bound cytochrome c oxidase from bovine heart. J Biol Chem. 1975 Nov 25;250(22):8598–8603. [PubMed] [Google Scholar]
  9. Fu J. L., Donner D. B., Moore D. E., Hess G. P. Allosteric interactions between the membrane-bound acetylcholine receptor and chemical mediators: equilibrium measurements. Biochemistry. 1977 Feb 22;16(4):678–684. doi: 10.1021/bi00623a019. [DOI] [PubMed] [Google Scholar]
  10. Gibson R. E., Juni S., O'Brien R. D. Monovalent ion effects on acetylcholine receptor from Torpedo californica. Arch Biochem Biophys. 1977 Feb;179(1):183–188. doi: 10.1016/0003-9861(77)90102-3. [DOI] [PubMed] [Google Scholar]
  11. Grünhagen H. H., Iwatsubo M., Changeux J. P. Fast kinetic studies on the interaction of cholinergic agonists with the membrane-bound acetylcholine receptor from Torpedo marmorata as revealed by quinacrine fluorescence. Eur J Biochem. 1977 Oct 17;80(1):225–242. doi: 10.1111/j.1432-1033.1977.tb11875.x. [DOI] [PubMed] [Google Scholar]
  12. Hammes G. G., Wu C. W. Kinetics of allosteric enzymes. Annu Rev Biophys Bioeng. 1974;3(0):1–33. doi: 10.1146/annurev.bb.03.060174.000245. [DOI] [PubMed] [Google Scholar]
  13. Hess G. P., Andrews J. P. Functional acetylcholine receptor--electroplax membrane microsacs (vesicles): purification and characterization. Proc Natl Acad Sci U S A. 1977 Feb;74(2):482–486. doi: 10.1073/pnas.74.2.482. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Hess G. P., Andrews J. P., Struve G. E. Apparent cooperative effects in acetylcholine receptor-mediated ion flux electroplax membrane preparations. Biochem Biophys Res Commun. 1976 Apr 5;69(3):830–837. doi: 10.1016/0006-291x(76)90950-5. [DOI] [PubMed] [Google Scholar]
  15. Hess G. P., Andrews J. P., Struve G. E., Goombs S. E. Acetylcholine-receptor-mediated ion flux in electroplax membrane preparations. Proc Natl Acad Sci U S A. 1975 Nov;72(11):4371–4375. doi: 10.1073/pnas.72.11.4371. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Hess G. P., Bulger J. E., Fu J. J., Hindy E. F., Silberstein R. J. Allosteric interactions of the membrane-bound acetylcholine reception: kinetic studies with alpha-bungarotoxin. Biochem Biophys Res Commun. 1975 Jan 2;64(3):1018–1027. doi: 10.1016/0006-291x(75)90149-7. [DOI] [PubMed] [Google Scholar]
  17. KATZ B., THESLEFF S. A study of the desensitization produced by acetylcholine at the motor end-plate. J Physiol. 1957 Aug 29;138(1):63–80. doi: 10.1113/jphysiol.1957.sp005838. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. KEYNES R. D., MARTINS-FERREIRA H. Membrane potentials in the electroplates of the electric eel. J Physiol. 1953 Feb 27;119(2-3):315–351. doi: 10.1113/jphysiol.1953.sp004849. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Katz B., Miledi R. The statistical nature of the acetycholine potential and its molecular components. J Physiol. 1972 Aug;224(3):665–699. doi: 10.1113/jphysiol.1972.sp009918. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. LOWRY O. H., ROSEBROUGH N. J., FARR A. L., RANDALL R. J. Protein measurement with the Folin phenol reagent. J Biol Chem. 1951 Nov;193(1):265–275. [PubMed] [Google Scholar]
  21. Lee C. Y. Chemistry and pharmacology of polypeptide toxins in snake venoms. Annu Rev Pharmacol. 1972;12:265–286. doi: 10.1146/annurev.pa.12.040172.001405. [DOI] [PubMed] [Google Scholar]
  22. Lester H. A., Changeux J. P., Sheridan R. E. Conductance increases produced by bath application of cholinergic agonists to Electrophorus electroplaques. J Gen Physiol. 1975 Jun;65(6):797–816. doi: 10.1085/jgp.65.6.797. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Maelicke A., Fulpius B. W., Klett R. P., Reich E. Acetylcholine receptor. Responses to drug binding. J Biol Chem. 1977 Jul 25;252(14):4811–4830. [PubMed] [Google Scholar]
  24. NACHMANSOHN D. Metabolism and function of the nerve cell. Harvey Lect. 1953;49:57–99. [PubMed] [Google Scholar]
  25. Neumann E., Chang H. W. Dynamic properties of isolated acetylcholine receptor protein: kinetics of the binding of acetylcholine and Ca ions. Proc Natl Acad Sci U S A. 1976 Nov;73(11):3994–3998. doi: 10.1073/pnas.73.11.3994. [DOI] [PMC free article] [PubMed] [Google Scholar]
  26. Palfrey C., Littauer U. Z. Sodium-dependent efflux of K+ and Rb+ through the activated sodium channel of neuroblastoma cells. Biochem Biophys Res Commun. 1976 Sep 7;72(1):209–215. doi: 10.1016/0006-291x(76)90981-5. [DOI] [PubMed] [Google Scholar]
  27. Pasternak G. W., Snyder S. H. Identification of novel high affinity opiate receptor binding in rat brain. Nature. 1975 Feb 13;253(5492):563–565. doi: 10.1038/253563a0. [DOI] [PubMed] [Google Scholar]
  28. Racker E. The two faces of the inner mitochondrial membrane. Essays Biochem. 1970;6:1–22. [PubMed] [Google Scholar]
  29. Schimerlik M., Raftery M. A. A fluorescence probe of acetylcholine receptor conformation and local anesthetic binding. Biochem Biophys Res Commun. 1976 Dec 6;73(3):607–613. doi: 10.1016/0006-291x(76)90853-6. [DOI] [PubMed] [Google Scholar]
  30. Sheridan R. E., Lester H. A. Relaxation measurements on the acetylcholine receptor. Proc Natl Acad Sci U S A. 1975 Sep;72(9):3496–3500. doi: 10.1073/pnas.72.9.3496. [DOI] [PMC free article] [PubMed] [Google Scholar]
  31. Sugiyama H., Changeux J. P. Interconversion between different states of affinity for acetylcholine of the cholinergic receptor protein from Torpedo marmorata. Eur J Biochem. 1975 Jul 15;55(3):505–515. doi: 10.1111/j.1432-1033.1975.tb02188.x. [DOI] [PubMed] [Google Scholar]
  32. Sugiyama H., Popot J. L., Changeux J. P. Studies on the electrogenic action of acetylcholine with Torpedo marmorata electric organ. III. Pharmocological desensitization in vitro of the receptor-rich membrane fragments by cholinergic agonists. J Mol Biol. 1976 Sep 25;106(3):485–496. doi: 10.1016/0022-2836(76)90248-5. [DOI] [PubMed] [Google Scholar]
  33. Weiland G., Georgia B., Lappi S., Chignell C. F., Taylor P. Kinetics of agonist-mediated transitions in state of the cholinergic receptor. J Biol Chem. 1977 Nov 10;252(21):7648–7656. [PubMed] [Google Scholar]

Articles from Proceedings of the National Academy of Sciences of the United States of America are provided here courtesy of National Academy of Sciences

RESOURCES