Skip to main content
Biophysical Journal logoLink to Biophysical Journal
. 1984 Sep;46(3):413–418. doi: 10.1016/S0006-3495(84)84037-0

A low voltage-activated calcium conductance in embryonic chick sensory neurons.

E Carbone, H D Lux
PMCID: PMC1434947  PMID: 6487739

Abstract

Isolated Ca currents in cultured dorsal root ganglion (DRG) cells were studied using the patch clamp technique. The currents persisted in the presence of 30 microM tetrodotoxin (TTX) or when external Na was replaced by choline. They were fully blocked by millimolar additions of Cd2+ and Ni2+ to the bath. Two components of an inward-going Ca current were observed. In 5 mM external Ca, a current of small amplitude, turned on already during steps changes to -60 mV membrane potential, leveled off at -30 mV to a value of approximately 0.2 nA. A second, larger current component, which resembled the previously described Ca current in other cells, appeared at more positive voltages (-20 to -10 mV) and had a maximum approximately 0 mV. The current component activated at the more negative membrane potentials showed the stronger dependence on external Ca. The presence of a time- and a voltage-dependent activation was indicated by the current's sigmoidal rise, which became faster with increased depolarization. Its tail currents were generally slower than those associated with the Ca currents of larger amplitude. From -60 mV holding potential, the maximum obtainable amplitude of the low depolarization-activated current was only one-tenth of that achieved from a holding potential of -90 mV. Voltage-dependent inactivation of this current component was fast compared with that of the other component. The properties of this low voltage-activated and fully inactivating Ca current suggest it is the same as the inward current that has been postulated in several central neurons (Llinas, R., and Y. Yarom, 1981, J. Physiol. (Lond.), 315:569-584), which produce depolarizing potential waves and burst-firing only when membrane hyperpolarization precedes.

Full text

PDF
413

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. Sodium and calcium gating currents in an Aplysia neurone. J Physiol. 1979 Jun;291:467–481. doi: 10.1113/jphysiol.1979.sp012826. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Akaike N., Lee K. S., Brown A. M. The calcium current of Helix neuron. J Gen Physiol. 1978 May;71(5):509–531. doi: 10.1085/jgp.71.5.509. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Barde Y. A., Edgar D., Thoenen H. Sensory neurons in culture: changing requirements for survival factors during embryonic development. Proc Natl Acad Sci U S A. 1980 Feb;77(2):1199–1203. doi: 10.1073/pnas.77.2.1199. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Brown A. M., Tsuda Y., Wilson D. L. A description of activation and conduction in calcium channels based on tail and turn-on current measurements in the snail. J Physiol. 1983 Nov;344:549–583. doi: 10.1113/jphysiol.1983.sp014956. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Chandler W. K., Meves H. Slow changes in membrane permeability and long-lasting action potentials in axons perfused with fluoride solutions. J Physiol. 1970 Dec;211(3):707–728. doi: 10.1113/jphysiol.1970.sp009300. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Dunlap K., Fischbach G. D. Neurotransmitters decrease the calcium conductance activated by depolarization of embryonic chick sensory neurones. J Physiol. 1981 Aug;317:519–535. doi: 10.1113/jphysiol.1981.sp013841. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Fenwick E. M., Marty A., Neher E. Sodium and calcium channels in bovine chromaffin cells. J Physiol. 1982 Oct;331:599–635. doi: 10.1113/jphysiol.1982.sp014394. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. 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]
  9. 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]
  10. 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]
  11. Hamill O. P., Marty A., Neher E., Sakmann B., Sigworth F. J. Improved patch-clamp techniques for high-resolution current recording from cells and cell-free membrane patches. Pflugers Arch. 1981 Aug;391(2):85–100. doi: 10.1007/BF00656997. [DOI] [PubMed] [Google Scholar]
  12. Kameyama M. Ionic currents in cultured dorsal root ganglion cells from adult guinea pigs. J Membr Biol. 1983;72(3):195–203. doi: 10.1007/BF01870586. [DOI] [PubMed] [Google Scholar]
  13. 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]
  14. Kostyuk P. G., Veselovsky N. S., Tsyndrenko A. Y. Ionic currents in the somatic membrane of rat dorsal root ganglion neurons-I. Sodium currents. Neuroscience. 1981;6(12):2423–2430. doi: 10.1016/0306-4522(81)90088-9. [DOI] [PubMed] [Google Scholar]
  15. Llinás R., Jahnsen H. Electrophysiology of mammalian thalamic neurones in vitro. Nature. 1982 Jun 3;297(5865):406–408. doi: 10.1038/297406a0. [DOI] [PubMed] [Google Scholar]
  16. Llinás R., Yarom Y. Properties and distribution of ionic conductances generating electroresponsiveness of mammalian inferior olivary neurones in vitro. J Physiol. 1981 Jun;315:569–584. doi: 10.1113/jphysiol.1981.sp013764. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. 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]
  18. Moolenaar W. H., Spector I. Ionic currents in cultured mouse neuroblastoma cells under voltage-clamp conditions. J Physiol. 1978 May;278:265–286. doi: 10.1113/jphysiol.1978.sp012303. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Neumcke B., Fox J. M., Drouin H., Schwarz W. Kinetics of the slow variation of peak sodium current in the membrane of myelinated nerve following changes of holding potential or extracellular pH. Biochim Biophys Acta. 1976 Mar 5;426(2):245–257. doi: 10.1016/0005-2736(76)90335-7. [DOI] [PubMed] [Google Scholar]
  20. Reuter H. Calcium channel modulation by neurotransmitters, enzymes and drugs. Nature. 1983 Feb 17;301(5901):569–574. doi: 10.1038/301569a0. [DOI] [PubMed] [Google Scholar]
  21. Sigworth F. J., Neher E. Single Na+ channel currents observed in cultured rat muscle cells. Nature. 1980 Oct 2;287(5781):447–449. doi: 10.1038/287447a0. [DOI] [PubMed] [Google Scholar]
  22. Whitmore I., Gosling J. A., Gilpin S. A. A comparison between the physiological and histochemical characterisation of urethral striated muscle in the guinea pig. Pflugers Arch. 1984 Jan;400(1):40–43. doi: 10.1007/BF00670534. [DOI] [PubMed] [Google Scholar]

Articles from Biophysical Journal are provided here courtesy of The Biophysical Society

RESOURCES