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. 1975 Jul;249(2):253–268. doi: 10.1113/jphysiol.1975.sp011014

Voltage-clamp studies of the calcium inward current in an identified snail neurone: comparison with the sodium inward current.

N B Standen
PMCID: PMC1309573  PMID: 1177093

Abstract

1. Membrane currents were recorded under voltage clamp from cell A of the snail Helix aspersa. 2. In sodium-free saline the inward current was reduced to 75% of that in normal saline (containing both sodium and calcium). 3. The inward current in sodium-free saline was dependent on the external calcium concentration. 4. Calcium-free saline reduced the inward current to 30% of that in normal saline. (Na, Ca)-free saline abolished the inward current. 5. Changes in calcium concentration shifted the curve relating calcium conductance to membrane potential along the voltage axis. 6. Inactivation of inward current in both normal saline and sodium-free saline developed exponentially with time. 7. Steady-state inactivation of calcium inward current was similar to that for sodium current and it is concluded that the conductance mechanisms for these two ions bear a close resemblance.

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Selected References

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

  1. ADELMAN W. J., TAYLOR R. E. Leakage current rectification in the squid giant axon. Nature. 1961 Jun 3;190:883–885. doi: 10.1038/190883a0. [DOI] [PubMed] [Google Scholar]
  2. Baker P. F., Meves H., Ridgway E. B. Calcium entry in response to maintained depolarization of squid axons. J Physiol. 1973 Jun;231(3):527–548. doi: 10.1113/jphysiol.1973.sp010247. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Beeler G. W., Jr, Reuter H. Membrane calcium current in ventricular myocardial fibres. J Physiol. 1970 Mar;207(1):191–209. doi: 10.1113/jphysiol.1970.sp009056. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Connor J. A., Stevens C. F. Voltage clamp studies of a transient outward membrane current in gastropod neural somata. J Physiol. 1971 Feb;213(1):21–30. doi: 10.1113/jphysiol.1971.sp009365. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Ebashi S., Endo M. Calcium ion and muscle contraction. Prog Biophys Mol Biol. 1968;18:123–183. doi: 10.1016/0079-6107(68)90023-0. [DOI] [PubMed] [Google Scholar]
  6. Geduldig D., Gruener R. Voltage clamp of the Aplysia giant neurone: early sodium and calcium currents. J Physiol. 1970 Nov;211(1):217–244. doi: 10.1113/jphysiol.1970.sp009276. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. HAGIWARA S., SAITO N. Voltage-current relations in nerve cell membrane of Onchidium verruculatum. J Physiol. 1959 Oct;148:161–179. doi: 10.1113/jphysiol.1959.sp006279. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. HODGKIN A. L., HUXLEY A. F. Currents carried by sodium and potassium ions through the membrane of the giant axon of Loligo. J Physiol. 1952 Apr;116(4):449–472. doi: 10.1113/jphysiol.1952.sp004717. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. HODGKIN A. L., HUXLEY A. F., KATZ B. Measurement of current-voltage relations in the membrane of the giant axon of Loligo. J Physiol. 1952 Apr;116(4):424–448. doi: 10.1113/jphysiol.1952.sp004716. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. HODGKIN A. L., HUXLEY A. F. The dual effect of membrane potential on sodium conductance in the giant axon of Loligo. J Physiol. 1952 Apr;116(4):497–506. doi: 10.1113/jphysiol.1952.sp004719. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Hille B. Charges and potentials at the nerve surface. Divalent ions and pH. J Gen Physiol. 1968 Feb;51(2):221–236. doi: 10.1085/jgp.51.2.221. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Hubbard J. I. Mechanism of transmitter release. Prog Biophys Mol Biol. 1970;21:33–124. [PubMed] [Google Scholar]
  13. Klee M. R., Faber D. S., Heiss W. D. Strychnine- and pentylenetetrazol-induced changes of excitability in aplysia neurons. Science. 1973 Mar 16;179(4078):1133–1136. doi: 10.1126/science.179.4078.1133. [DOI] [PubMed] [Google Scholar]
  14. Kostyuk P. G., Krishtal O. A., Doroshenko P. A. Calcium currents in snail neurones. II. The effect of external calcium concentration on the calcium inward current. Pflugers Arch. 1974 Apr 11;348(2):95–104. doi: 10.1007/BF00586472. [DOI] [PubMed] [Google Scholar]
  15. Krishtal O. A., Magura I. S. Calcium ions as inward current carriers in mollusc neurones. Comp Biochem Physiol. 1970 Aug 15;35(4):857–866. doi: 10.1016/0010-406x(70)90080-0. [DOI] [PubMed] [Google Scholar]
  16. Meech R. W., Standen N. B. Potassium activation in Helix aspersa neurones under voltage clamp: a component mediated by calcium influx. J Physiol. 1975 Jul;249(2):211–239. doi: 10.1113/jphysiol.1975.sp011012. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Meech R. W. The sensitivity of Helix aspersa neurones to injected calcium ions. J Physiol. 1974 Mar;237(2):259–277. doi: 10.1113/jphysiol.1974.sp010481. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Neher E. Two fast transient current components during voltage clamp on snail neurons. J Gen Physiol. 1971 Jul;58(1):36–53. doi: 10.1085/jgp.58.1.36. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Reuter H. Divalent cations as charge carriers in excitable membranes. Prog Biophys Mol Biol. 1973;26:1–43. doi: 10.1016/0079-6107(73)90016-3. [DOI] [PubMed] [Google Scholar]
  20. Rubin R. P. The role of calcium in the release of neurotransmitter substances and hormones. Pharmacol Rev. 1970 Sep;22(3):389–428. [PubMed] [Google Scholar]
  21. Standen N. B. Calcium and sodium ions as charge carriers in the action potential of an identified snail neurone. J Physiol. 1975 Jul;249(2):241–252. doi: 10.1113/jphysiol.1975.sp011013. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Standen N. B. Properties of a calcium channel in snail neurones. Nature. 1974 Jul 26;250(464):340–342. doi: 10.1038/250340a0. [DOI] [PubMed] [Google Scholar]
  23. Thomas R. C. Intracellular sodium activity and the sodium pump in snail neurones. J Physiol. 1972 Jan;220(1):55–71. doi: 10.1113/jphysiol.1972.sp009694. [DOI] [PMC free article] [PubMed] [Google Scholar]

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