Skip to main content
NCBI home page
The Journal of Physiology logoLink to The Journal of Physiology
. 1989 May;412:197–220. doi: 10.1113/jphysiol.1989.sp017611

Voltage-dependent and calcium-dependent inactivation of calcium channel current in identified snail neurones.

M J Gutnick 1, H D Lux 1, D Swandulla 1, H Zucker 1
PMCID: PMC1190571  PMID: 2557426

Abstract

1. The dependence of Ca2+ current inactivation on membrane potential and intracellular Ca2+ concentration ([Ca2+]i) was studied in TEA-loaded, identified Helix neurones which possess a single population of high-voltage-activated Ca2+ channels. During prolonged depolarization, the Ca2+ current declined from its peak with two clearly distinct phases. The time course of its decay was readily fitted by a double-exponential function. 2. In double-pulse experiments, the relationship between the magnitude of the Ca2+ current and the amount of Ca2+ inactivation was not linear, and considerable inactivation was present, even when conditioning pulses were to levels of depolarization so great that Ca2+ currents were near zero. Similar results were obtained when external Ca2+ was replaced by Ba2+. 3. In double-pulse experiments, hyperpolarization during the interpulse interval served to reprime a portion of the inactivated Ca2+ current for subsequent activation. The extent of repriming increased with hyperpolarization, reaching a maximum between -130 and -150 mV. The effectiveness of repriming hyperpolarizations was considerably increased when Ca2+ was replaced by Ba2+. 4. A significant fraction of inactivated Ca2+ channels can be recovered during hyperpolarizing pulses lasting only milliseconds. If hyperpolarizing pulses were applied before substantial inactivation of Ca2+ current, Ca2+ channels remained available for activation despite considerable Ca2+ entry. 5. The relationship between [Ca2+]i and inactivation was investigated by quantitatively injecting Ca2+-buffered solutions into the cells. The time course of Ca2+ current inactivation was unchanged at free [Ca2+] between 1 x 10(-7) and 1 x 10(-5) M. From 1 x 10(-7) to 1 x 10(-9) M, inactivation became progressively slower, mainly due to a decrease of the amplitude ratio (fast/slow) of the two components of inactivation, which fell from about unity to near zero at 1 x 10(-9) M. In double-pulse experiments, recovery from inactivation was enhanced in neurones that had been injected with Ca2+ chelator. 6. We conclude that inactivation of Ca2+ channels in these neurones depends on both [Ca2+]i and membrane potential. The voltage-dependent process may serve as a mechanism to quickly recover inactivated Ca2+ channels during repetitive firing despite considerable Ca2+ influx. 7. The results are discussed in the framework of a model which is based on two states of inactivation, INV and INCA, which represent different conformations of the inactivating substrate, and which are both reached from a lumped state of activation (A). Inactivation leads to high occupancy of INV during depolarization.(ABSTRACT TRUNCATED AT 400 WORDS)

Full text

PDF
197

Selected References

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

  1. Adams D. J., Gage P. W. Divalent ion currents and the delayed potassium conductance in an Aplysia neurone. J Physiol. 1980 Jul;304:297–313. doi: 10.1113/jphysiol.1980.sp013325. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Akaike N., Tsuda Y., Oyama Y. Separation of current- and voltage-dependent inactivation of calcium current in frog sensory neuron. Neurosci Lett. 1988 Jan 11;84(1):46–50. doi: 10.1016/0304-3940(88)90335-7. [DOI] [PubMed] [Google Scholar]
  3. Argibay J. A., Fischmeister R., Hartzell H. C. Inactivation, reactivation and pacing dependence of calcium current in frog cardiocytes: correlation with current density. J Physiol. 1988 Jul;401:201–226. doi: 10.1113/jphysiol.1988.sp017158. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Armstrong C. M., Matteson D. R. Two distinct populations of calcium channels in a clonal line of pituitary cells. Science. 1985 Jan 4;227(4682):65–67. doi: 10.1126/science.2578071. [DOI] [PubMed] [Google Scholar]
  5. Ashcroft F. M., Stanfield P. R. Calcium dependence of the inactivation of calcium currents in skeletal muscle fibers of an insect. Science. 1981 Jul 10;213(4504):224–226. doi: 10.1126/science.213.4504.224. [DOI] [PubMed] [Google Scholar]
  6. Bean B. P. Two kinds of calcium channels in canine atrial cells. Differences in kinetics, selectivity, and pharmacology. J Gen Physiol. 1985 Jul;86(1):1–30. doi: 10.1085/jgp.86.1.1. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Bossu J. L., Feltz A., Thomann J. M. Depolarization elicits two distinct calcium currents in vertebrate sensory neurones. Pflugers Arch. 1985 Apr;403(4):360–368. doi: 10.1007/BF00589247. [DOI] [PubMed] [Google Scholar]
  8. Brehm P., Eckert R. Calcium entry leads to inactivation of calcium channel in Paramecium. Science. 1978 Dec 15;202(4373):1203–1206. doi: 10.1126/science.103199. [DOI] [PubMed] [Google Scholar]
  9. Brehm P., Eckert R., Tillotson D. Calcium-mediated inactivation of calcium current in Paramecium. J Physiol. 1980 Sep;306:193–203. doi: 10.1113/jphysiol.1980.sp013391. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Brown A. M., Lux H. D., Wilson D. L. Activation and inactivation of single calcium channels in snail neurons. J Gen Physiol. 1984 May;83(5):751–769. doi: 10.1085/jgp.83.5.751. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Brown A. M., Morimoto K., Tsuda Y., wilson D. L. Calcium current-dependent and voltage-dependent inactivation of calcium channels in Helix aspersa. J Physiol. 1981 Nov;320:193–218. doi: 10.1113/jphysiol.1981.sp013944. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Carbone E., Lux H. D. A low voltage-activated calcium conductance in embryonic chick sensory neurons. Biophys J. 1984 Sep;46(3):413–418. doi: 10.1016/S0006-3495(84)84037-0. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Chad J. E., Eckert R. An enzymatic mechanism for calcium current inactivation in dialysed Helix neurones. J Physiol. 1986 Sep;378:31–51. doi: 10.1113/jphysiol.1986.sp016206. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Chad J. E., Eckert R. Calcium domains associated with individual channels can account for anomalous voltage relations of CA-dependent responses. Biophys J. 1984 May;45(5):993–999. doi: 10.1016/S0006-3495(84)84244-7. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Chad J., Eckert R., Ewald D. Kinetics of calcium-dependent inactivation of calcium current in voltage-clamped neurones of Aplysia californica. J Physiol. 1984 Feb;347:279–300. doi: 10.1113/jphysiol.1984.sp015066. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Colquhoun D., Hawkes A. G. Relaxation and fluctuations of membrane currents that flow through drug-operated channels. Proc R Soc Lond B Biol Sci. 1977 Nov 14;199(1135):231–262. doi: 10.1098/rspb.1977.0137. [DOI] [PubMed] [Google Scholar]
  17. Connor J. A. Calcium current in molluscan neurones: measurement under conditions which maximize its visibility. J Physiol. 1979 Jan;286:41–60. doi: 10.1113/jphysiol.1979.sp012606. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Deitmer J. W. Evidence for two voltage-dependent calcium currents in the membrane of the ciliate Stylonychia. J Physiol. 1984 Oct;355:137–159. doi: 10.1113/jphysiol.1984.sp015411. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Eckert R., Chad J. E. Inactivation of Ca channels. Prog Biophys Mol Biol. 1984;44(3):215–267. doi: 10.1016/0079-6107(84)90009-9. [DOI] [PubMed] [Google Scholar]
  20. Eckert R., Ewald D. Inactivation of calcium conductance characterized by tail current measurements in neurones of Aplysia californica. J Physiol. 1983 Dec;345:549–565. doi: 10.1113/jphysiol.1983.sp014996. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Eckert R., Tillotson D. L. Calcium-mediated inactivation of the calcium conductance in caesium-loaded giant neurones of Aplysia californica. J Physiol. 1981 May;314:265–280. doi: 10.1113/jphysiol.1981.sp013706. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Fedulova S. A., Kostyuk P. G., Veselovsky N. S. Two types of calcium channels in the somatic membrane of new-born rat dorsal root ganglion neurones. J Physiol. 1985 Feb;359:431–446. doi: 10.1113/jphysiol.1985.sp015594. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Hadley R. W., Hume J. R. An intrinsic potential-dependent inactivation mechanism associated with calcium channels in guinea-pig myocytes. J Physiol. 1987 Aug;389:205–222. doi: 10.1113/jphysiol.1987.sp016654. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. Hagiwara S., Byerly L. Calcium channel. Annu Rev Neurosci. 1981;4:69–125. doi: 10.1146/annurev.ne.04.030181.000441. [DOI] [PubMed] [Google Scholar]
  25. Harafuji H., Ogawa Y. Re-examination of the apparent binding constant of ethylene glycol bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid with calcium around neutral pH. J Biochem. 1980 May;87(5):1305–1312. doi: 10.1093/oxfordjournals.jbchem.a132868. [DOI] [PubMed] [Google Scholar]
  26. Hofmeier G., Lux H. D. The time courses of intracellular free calcium and related electrical effects after injection of CaCl2 into neurons of the snail, Helix pomatia. Pflugers Arch. 1981 Sep;391(3):242–251. doi: 10.1007/BF00596178. [DOI] [PubMed] [Google Scholar]
  27. Kass R. S., Sanguinetti M. C. Inactivation of calcium channel current in the calf cardiac Purkinje fiber. Evidence for voltage- and calcium-mediated mechanisms. J Gen Physiol. 1984 Nov;84(5):705–726. doi: 10.1085/jgp.84.5.705. [DOI] [PMC free article] [PubMed] [Google Scholar]
  28. Kostyuk P. G. Calcium ionic channels in electrically excitable membrane. Neuroscience. 1980;5(6):945–959. doi: 10.1016/0306-4522(80)90178-5. [DOI] [PubMed] [Google Scholar]
  29. Kostyuk P. G., Krishtal O. A., Shakhovalov Y. A. Separation of sodium and calcium currents in the somatic membrane of mollusc neurones. J Physiol. 1977 Sep;270(3):545–568. doi: 10.1113/jphysiol.1977.sp011968. [DOI] [PMC free article] [PubMed] [Google Scholar]
  30. Lee K. S., Marban E., Tsien R. W. Inactivation of calcium channels in mammalian heart cells: joint dependence on membrane potential and intracellular calcium. J Physiol. 1985 Jul;364:395–411. doi: 10.1113/jphysiol.1985.sp015752. [DOI] [PMC free article] [PubMed] [Google Scholar]
  31. Lux H. D., Brown A. M. Patch and whole cell calcium currents recorded simultaneously in snail neurons. J Gen Physiol. 1984 May;83(5):727–750. doi: 10.1085/jgp.83.5.727. [DOI] [PMC free article] [PubMed] [Google Scholar]
  32. Lux H. D., Brown A. M. Single channel studies on inactivation of calcium currents. Science. 1984 Jul 27;225(4660):432–434. doi: 10.1126/science.6330896. [DOI] [PubMed] [Google Scholar]
  33. Lux H. D., Hofmeier G. Properties of a calcium- and voltage-activated potassium current in Helix pomatia neurons. Pflugers Arch. 1982 Jul;394(1):61–69. doi: 10.1007/BF01108309. [DOI] [PubMed] [Google Scholar]
  34. Magura I. S. Long-lasting inward current in snail neurons in barium solutions in voltage-clamp conditions. J Membr Biol. 1977 Jul 14;35(3):239–256. doi: 10.1007/BF01869952. [DOI] [PubMed] [Google Scholar]
  35. Nowycky M. C., Fox A. P., Tsien R. W. Three types of neuronal calcium channel with different calcium agonist sensitivity. Nature. 1985 Aug 1;316(6027):440–443. doi: 10.1038/316440a0. [DOI] [PubMed] [Google Scholar]
  36. Plant T. D., Standen N. B. Calcium current inactivation in identified neurones of Helix aspersa. J Physiol. 1981 Dec;321:273–285. doi: 10.1113/jphysiol.1981.sp013983. [DOI] [PMC free article] [PubMed] [Google Scholar]
  37. Plant T. D., Standen N. B., Ward T. A. The effects of injection of calcium ions and calcium chelators on calcium channel inactivation in Helix neurones. J Physiol. 1983 Jan;334:189–212. doi: 10.1113/jphysiol.1983.sp014489. [DOI] [PMC free article] [PubMed] [Google Scholar]
  38. Quast U., Labhardt A. M., Doyle V. M. Stopped-flow kinetics of the interaction of the fluorescent calcium indicator Quin 2 with calcium ions. Biochem Biophys Res Commun. 1984 Sep 17;123(2):604–611. doi: 10.1016/0006-291x(84)90272-9. [DOI] [PubMed] [Google Scholar]
  39. Standen N. B., Stanfield P. R. A binding-site model for calcium channel inactivation that depends on calcium entry. Proc R Soc Lond B Biol Sci. 1982 Dec 22;217(1206):101–110. doi: 10.1098/rspb.1982.0097. [DOI] [PubMed] [Google Scholar]
  40. Swandulla D., Carbone E., Schäfer K., Lux H. D. Effect of menthol on two types of Ca currents in cultured sensory neurons of vertebrates. Pflugers Arch. 1987 Jun;409(1-2):52–59. doi: 10.1007/BF00584749. [DOI] [PubMed] [Google Scholar]
  41. Swandulla D., Schäfer K., Lux H. D. Calcium channel current inactivation is selectively modulated by menthol. Neurosci Lett. 1986 Jul 11;68(1):23–28. doi: 10.1016/0304-3940(86)90223-5. [DOI] [PubMed] [Google Scholar]
  42. Thompson S., Coombs J. Spatial distribution of Ca currents in molluscan neuron cell bodies and regional differences in the strength of inactivation. J Neurosci. 1988 Jun;8(6):1929–1939. doi: 10.1523/JNEUROSCI.08-06-01929.1988. [DOI] [PMC free article] [PubMed] [Google Scholar]
  43. Tillotson D. Inactivation of Ca conductance dependent on entry of Ca ions in molluscan neurons. Proc Natl Acad Sci U S A. 1979 Mar;76(3):1497–1500. doi: 10.1073/pnas.76.3.1497. [DOI] [PMC free article] [PubMed] [Google Scholar]
  44. Tsien R. W. Calcium channels in excitable cell membranes. Annu Rev Physiol. 1983;45:341–358. doi: 10.1146/annurev.ph.45.030183.002013. [DOI] [PubMed] [Google Scholar]
  45. Tsien R. Y. New calcium indicators and buffers with high selectivity against magnesium and protons: design, synthesis, and properties of prototype structures. Biochemistry. 1980 May 27;19(11):2396–2404. doi: 10.1021/bi00552a018. [DOI] [PubMed] [Google Scholar]
  46. Yatani A., Wilson D. L., Brown A. M. Recovery of Ca currents from inactivation: the roles of Ca influx, membrane potential, and cellular metabolism. Cell Mol Neurobiol. 1983 Dec;3(4):381–395. doi: 10.1007/BF00734718. [DOI] [PMC free article] [PubMed] [Google Scholar]
  47. Zucker R. S. Tetraethylammonium contains an impurity which alkalizes cytoplasm and reduce calcium buffering in neurons. Brain Res. 1981 Mar 16;208(2):473–478. doi: 10.1016/0006-8993(81)90580-1. [DOI] [PubMed] [Google Scholar]

Articles from The Journal of Physiology are provided here courtesy of The Physiological Society

RESOURCES