Skip to main content
PMC home page
The Journal of General Physiology logoLink to The Journal of General Physiology
. 1989 Jul 1;94(1):169–182. doi: 10.1085/jgp.94.1.169

Calcium currents in bullfrog sympathetic neurons. II. Inactivation

PMCID: PMC2228927  PMID: 2553857

Abstract

Calcium currents in bullfrog sympathetic neurons inactivate slowly and partially during depolarizations lasting 0.5-1 s. There is also a slower (minutes) inactivation process with a broad voltage dependence. An irreversible loss of current (rundown) is prominent with low concentrations of intracellular Ca2+ buffers, with either Ca2+ or Ba2+ as the charge carrier. The extent and rate of the more rapid inactivation process are maximal near the voltage at which the peak inward current is generated, suggesting that inactivation might be Ca2+ dependent. However, inactivation occurs with either Ca2+ or Ba2+ as the charge carrier, is not prevented by strong buffering of intracellular Ca2+ with 10 mM BAPTA, and varies little as the peak current is changed 10-fold by changing the divalent ion concentration. That is, rapid inactivation is not explained by simple versions of voltage, Ca2+- or current-dependent inactivation models. A model in which ion binding within the channel allows a slower, rate-limiting inactivation process fits some but not all of the observed features of inactivation. A purely voltage-dependent three-state cyclic model fits the data if microscopic inactivation is favored by hyperpolarization.

Full Text

The Full Text of this article is available as a PDF (792.5 KB).

Selected References

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

  1. Almers W., Fink R., Palade P. T. Calcium depletion in frog muscle tubules: the decline of calcium current under maintained depolarization. J Physiol. 1981 Mar;312:177–207. doi: 10.1113/jphysiol.1981.sp013623. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. 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]
  3. 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]
  4. Campbell D. L., Giles W. R., Hume J. R., Shibata E. F. Inactivation of calcium current in bull-frog atrial myocytes. J Physiol. 1988 Sep;403:287–315. doi: 10.1113/jphysiol.1988.sp017250. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Carbone E., Lux H. D. A low voltage-activated, fully inactivating Ca channel in vertebrate sensory neurones. Nature. 1984 Aug 9;310(5977):501–502. doi: 10.1038/310501a0. [DOI] [PubMed] [Google Scholar]
  6. 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]
  7. Chandler W. K., Meves H. Evidence for two types of sodium conductance in axons perfused with sodium fluoride solution. J Physiol. 1970 Dec;211(3):653–678. doi: 10.1113/jphysiol.1970.sp009298. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Cheung W. Y. Calmodulin: its potential role in cell proliferation and heavy metal toxicity. Fed Proc. 1984 Dec;43(15):2995–2999. [PubMed] [Google Scholar]
  9. Cota G., Nicola Siri L., Stefani E. Calcium channel inactivation in frog (Rana pipiens and Rana moctezuma) skeletal muscle fibres. J Physiol. 1984 Sep;354:99–108. doi: 10.1113/jphysiol.1984.sp015365. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. 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]
  11. 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]
  12. Fox A. P., Nowycky M. C., Tsien R. W. Kinetic and pharmacological properties distinguishing three types of calcium currents in chick sensory neurones. J Physiol. 1987 Dec;394:149–172. doi: 10.1113/jphysiol.1987.sp016864. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Fox J. M. Ultra-slow inactivation of the ionic currents through the membrane of myelinated nerve. Biochim Biophys Acta. 1976 Mar 5;426(2):232–244. doi: 10.1016/0005-2736(76)90334-5. [DOI] [PubMed] [Google Scholar]
  14. Ganitkevich VYa, Shuba M. F., Smirnov S. V. Calcium-dependent inactivation of potential-dependent calcium inward current in an isolated guinea-pig smooth muscle cell. J Physiol. 1987 Nov;392:431–449. doi: 10.1113/jphysiol.1987.sp016789. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Hagiwara S., Ozawa S., Sand O. Voltage clamp analysis of two inward current mechanisms in the egg cell membrane of a starfish. J Gen Physiol. 1975 May;65(5):617–644. doi: 10.1085/jgp.65.5.617. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Hirning L. D., Fox A. P., McCleskey E. W., Olivera B. M., Thayer S. A., Miller R. J., Tsien R. W. Dominant role of N-type Ca2+ channels in evoked release of norepinephrine from sympathetic neurons. Science. 1988 Jan 1;239(4835):57–61. doi: 10.1126/science.2447647. [DOI] [PubMed] [Google Scholar]
  17. Hoshi T., Rothlein J., Smith S. J. Facilitation of Ca2+-channel currents in bovine adrenal chromaffin cells. Proc Natl Acad Sci U S A. 1984 Sep;81(18):5871–5875. doi: 10.1073/pnas.81.18.5871. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Hoshi T., Smith S. J. Large depolarization induces long openings of voltage-dependent calcium channels in adrenal chromaffin cells. J Neurosci. 1987 Feb;7(2):571–580. doi: 10.1523/JNEUROSCI.07-02-00571.1987. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Jones S. W., Marks T. N. Calcium currents in bullfrog sympathetic neurons. I. Activation kinetics and pharmacology. J Gen Physiol. 1989 Jul;94(1):151–167. doi: 10.1085/jgp.94.1.151. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. 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]
  21. 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]
  22. Lipscombe D., Madison D. V., Poenie M., Reuter H., Tsien R. Y., Tsien R. W. Spatial distribution of calcium channels and cytosolic calcium transients in growth cones and cell bodies of sympathetic neurons. Proc Natl Acad Sci U S A. 1988 Apr;85(7):2398–2402. doi: 10.1073/pnas.85.7.2398. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Matteson D. R., Armstrong C. M. Properties of two types of calcium channels in clonal pituitary cells. J Gen Physiol. 1986 Jan;87(1):161–182. doi: 10.1085/jgp.87.1.161. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. 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]
  25. Wanke E., Ferroni A., Malgaroli A., Ambrosini A., Pozzan T., Meldolesi J. Activation of a muscarinic receptor selectively inhibits a rapidly inactivated Ca2+ current in rat sympathetic neurons. Proc Natl Acad Sci U S A. 1987 Jun;84(12):4313–4317. doi: 10.1073/pnas.84.12.4313. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from The Journal of General Physiology are provided here courtesy of The Rockefeller University Press

RESOURCES