Advertisement

The Journal of Membrane Biology

, Volume 70, Issue 3, pp 181–189 | Cite as

Energy profile of the calcium channel in the membrane of mollusc neurons

  • P. G. Kostyuk
  • S. L. Mironov
  • P. A. Doroshenko
Articles

Summary

The current-voltage characteristics of the inward calcium and barium currents at different concentrations of these ions in the extracellular solution have been measured on isolated neurons of the snailHelix pomatia intracellularly perfused with potassium-free solution containing 10mm EDTA. On the basis of these characteristics the energy profile of the calcium channel has been calculated using a model based on the absolute reaction rate theory developed by Eyring. The effect of changes of the near-membrane concentration of the penetrating ions due to the existence of fixed charges on the outer side of the membrane has been taken into account. A satisfactory description of the concentration-and potential-dependence of the calcium inward currents has been obtained based on a three-barrier model for the energy profile of the calcium channel. Calculated dissociation constants for the complexes of Ca2+ ions with the binding sites of the calcium channel have the following values:Kout=10mm andKin=2.5mm; and for the complexes of Ba2+ ions,Kout=91mm andKin=1.5mm. The outer binding site corresponds to the acidic group with pK=5.8. Comparison between these data and the values of pK for divalent cation complexes with different anionic groups of amino acids allowed us to suggest that the outer binding site contains only one carboxylic group. It was shown that the strength of cation binding to this group determines the conductance of the calcium channel.

Key Words

energy profile calcium channel mollusc neurons 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Akaike, N., Lee, K.S., Brown, A.M. 1978. The calcium current of Helix neuron.J. Gen. Physiol. 71:509–531Google Scholar
  2. Bayer, R.D., Kalusohe, R., Kaufman, R., Manhold, R. 1975. Inotropic and electrophysiological actions of verapamil and D600 in mammalian myocardium. III. Effects of optical isomers on transmembrane action potentials.Naunyn-Schmiedebergs. Arch. Pharmacol. 290:81–87Google Scholar
  3. Doroshenko, P.A., Kostyuk, P.G., Tsyndrenko, A.Ya. 1978. The investigation of reversal potential for the slow component of inward current in the membrane of mollusc neurons.Neurophysiology (USSR) 10:201–206Google Scholar
  4. Doroshenko, P.A., Tsyndrenko, A.Ya. 1978. The effect of intracellular Ca on the calcium inward current.Neurophysiology (USSR) 10:645–653Google Scholar
  5. Eyring, H., Lumry, R., Woodbury, J.W. 1949. Some recent applications of modern rate theory to physiological systems.Rec. Chem. Prog. 10:100–114Google Scholar
  6. Fedulova, S.A., Kostyuk, P.G., Veselovsky, N.S. 1981. Calcium hannels in the somatic membrane of rat dorsal root ganglion neurones. Effect of cAMP.Brain Res. 214:210–214Google Scholar
  7. Fleckenstein, A., Nakayama, K., Fleckenstein-Grün, G., Byon, Y.K. 1975. Interaction of vasoactive ions and drugs with Ca-dependent excitation-contraction coupling of vascular smooth muscle.In: Calcium Transport in Contraction and Secretion. E. Carafoli, editor. pp. 555–566. Elsevier, North-Holland, AmsterdamGoogle Scholar
  8. Hille, B. 1975. Ionic selectivity, saturation and block in sodium channels.J. Gen. Physiol. 66:535–560Google Scholar
  9. Hille, B., Schwartz, W. 1978. Potassium channels as multiion single-file pores.J. Gen. Physiol. 72:409–442Google Scholar
  10. Kostyuk, P.G., Krishtal, O.A. 1977a. Separation of sodium and calcium currents in the somatic membrane of mollusc neurones.J. Physiol. (London) 270:545–568Google Scholar
  11. Kostyuk, P.G., Krishtal, O.A. 1977b. Effects of calcium and calcium-chelating agents on the inward and outward current in the membrane of mollusc neurones.J. Physiol. (London) 270:569–580Google Scholar
  12. Kostyuk, P.G., Krishtal, O.A., Pidoplichko, V.I. 1978. The estimation of single calcium channel conductance using the current fluctuation method and EGTA effect.Dokl. Akad. Nauk SSSR 238:478–481Google Scholar
  13. Kostyuk, P.G., Krishtal, O.A., Pidoplichko, V.I. 1981. Calcium inward current and related charge movements in the membrane of snail neurones.J. Physiol (London) 310:723–745Google Scholar
  14. Kostyuk, P.G., Mironov, S.L. 1982. Theoretical description of calcium channel in the somatic membrane of rat dorsal root ganglion neurones.Neurophysiology (USSR) 14:94–101Google Scholar
  15. Kostyuk, P.G., Mironov, S.L., Doroshenko, P.A. 1980. Energy profile of the calcium channel in mollusc neurones.Dokl. Akad. Nauk SSSR 253:978–981Google Scholar
  16. Kostyuk, P.G., Mironov, S.L., Doroshenko, P.A., Ponomarev, V.N. 1982. Surface charge on the outer side of mollusc neuron membrane.J. Membrane Biol. 70:171–179Google Scholar
  17. Markin, V.S., Chizmadjev, Yu.A. 1974. The Induced Ion Transport. Nauka Publishing House, MoscowGoogle Scholar
  18. Martell, A.E., Smith, R.M. 1977. Critical Stability Constants. Plenum Press, New YorkGoogle Scholar
  19. Moelwyn-Hudges, E.A. 1971. The Chemical Statics and Kinetics of Solutions. Academic Press, New YorkGoogle Scholar
  20. Nachshen, D.A., Blaustein, M.P. 1979. Regulation of nerve terminal calcium channel selectivity by a weak acid site.Biophys. J. 26:329–334Google Scholar
  21. Naruševičius, E.V., Rapoport, M.Sh. 1979. The influence of membrane potential and extracellular concentration of Sr and Ca ions upon the inward current in dialyzed neurones ofHelix pomatia.Dokl. Akad. Nauk SSSR 246:217–219Google Scholar
  22. Rasmussen, H., Goodman, D.B.P. 1977. Relationships between calcium and cyclic nucleotides in cell activation.Physiol. Rev. 57:421–509Google Scholar
  23. Woodhull, A.M. 1973. Ionic blockage of sodium channels in nerve.J. Gen. Physiol. 61:687–708Google Scholar
  24. Yasui, S., Brown, A.M., Akaike, N., Lee, K.S. 1979. Rate theory model of the Ca channel.Biophys. J. 25:M-MP (Abstr.)Google Scholar

Copyright information

© Springer-Verlag New York Inc 1982

Authors and Affiliations

  • P. G. Kostyuk
    • 1
  • S. L. Mironov
    • 1
  • P. A. Doroshenko
    • 1
  1. 1.A.A. Bogomoletz Institute of PhysiologyAcademy of Sciences of the Ukrainian SSRKievUSSR

Personalised recommendations