Abstract
The modifications in the properties of voltage-gated Na+ channels caused by batrachotoxin were studied by using the patch clamp method for measuring single channel currents from excised membranes of N1E-115 neuroblastoma cells. The toxin-modified open state of the Na+ channel has a decreased conductance in comparison to that of normal Na+ channels. The lifetime of the modified open state is drastically prolonged, and channels now continue to open during a maintained depolarization so that the probability of a channel being open becomes constant. Modified and normal open states of Na+ channels coexist in batrachotoxin-exposed membrane patches. Unlike the normal condition, Na+ channels exposed to batrachotoxin open spontaneously at large negative potentials. These spontaneous openings apparently cause the toxin-induced increase in Na+ permeability which, in turn, causes membrane depolarization.
Full text
PDF




Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Albuquerque E. X., Daly J. W., Witkop B. Batrachotoxin: chemistry and pharmacology. Science. 1971 Jun 4;172(3987):995–1002. doi: 10.1126/science.172.3987.995. [DOI] [PubMed] [Google Scholar]
- Albuquerque E. X., Seyama I., Narahashi T. Characterization of batrachotoxin-induced depolarization of the squid giant axons. J Pharmacol Exp Ther. 1973 Feb;184(2):308–314. [PubMed] [Google Scholar]
- Catterall W. A. Activation of the action potential Na+ ionophore of cultured neuroblastoma cells by veratridine and batrachotoxin. J Biol Chem. 1975 Jun 10;250(11):4053–4059. [PubMed] [Google Scholar]
- Catterall W. A. Neurotoxins that act on voltage-sensitive sodium channels in excitable membranes. Annu Rev Pharmacol Toxicol. 1980;20:15–43. doi: 10.1146/annurev.pa.20.040180.000311. [DOI] [PubMed] [Google Scholar]
- Conti F., Hille B., Neumcke B., Nonner W., Stämpfli R. Conductance of the sodium channel in myelinated nerve fibres with modified sodium inactivation. J Physiol. 1976 Nov;262(3):729–742. doi: 10.1113/jphysiol.1976.sp011617. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Fukushima Y. Identification and kinetic properties of the current through a single Na+ channel. Proc Natl Acad Sci U S A. 1981 Feb;78(2):1274–1277. doi: 10.1073/pnas.78.2.1274. [DOI] [PMC free article] [PubMed] [Google Scholar]
- HODGKIN A. L., HUXLEY A. F. A quantitative description of membrane current and its application to conduction and excitation in nerve. J Physiol. 1952 Aug;117(4):500–544. doi: 10.1113/jphysiol.1952.sp004764. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 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]
- Horn R., Patlak J., Stevens C. F. Sodium channels need not open before they inactivate. Nature. 1981 Jun 4;291(5814):426–427. doi: 10.1038/291426a0. [DOI] [PubMed] [Google Scholar]
- Huang L. Y., Moran N., Ehrenstein G. Batrachotoxin modifies the gating kinetics of sodium channels in internally perfused neuroblastoma cells. Proc Natl Acad Sci U S A. 1982 Mar;79(6):2082–2085. doi: 10.1073/pnas.79.6.2082. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Khodorov B. I., Neumcke B., Schwarz W., Stämpfli R. Fluctuation analysis of Na+ channels modified by batrachotoxin in myelinated nerve. Biochim Biophys Acta. 1981 Oct 20;648(1):93–99. doi: 10.1016/0005-2736(81)90128-0. [DOI] [PubMed] [Google Scholar]
- Khodorov B. I., Peganov E. M., Revenko S. V., Shishkova L. D. Sodium currents in voltage clamped nerve fiber of frog under the combined action of batrachotoxin and procaine. Brain Res. 1975 Feb 14;84(3):541–546. doi: 10.1016/0006-8993(75)90771-4. [DOI] [PubMed] [Google Scholar]
- Khodorov B. I., Revenko S. V. Further analysis of the mechanisms of action of batrachotoxin on the membrane of myelinated nerve. Neuroscience. 1979;4(9):1315–1330. doi: 10.1016/0306-4522(79)90159-3. [DOI] [PubMed] [Google Scholar]
- Kimhi Y., Palfrey C., Spector I., Barak Y., Littauer U. Z. Maturation of neuroblastoma cells in the presence of dimethylsulfoxide. Proc Natl Acad Sci U S A. 1976 Feb;73(2):462–466. doi: 10.1073/pnas.73.2.462. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Narahashi T., Albuquerque E. X., Deguchi T. Effects of batrachotoxin on membrane potential and conductance of squid giant axons. J Gen Physiol. 1971 Jul;58(1):54–70. doi: 10.1085/jgp.58.1.54. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Narahashi T. Chemicals as tools in the study of excitable membranes. Physiol Rev. 1974 Oct;54(4):813–889. doi: 10.1152/physrev.1974.54.4.813. [DOI] [PubMed] [Google Scholar]
- Patlak J., Horn R. Effect of N-bromoacetamide on single sodium channel currents in excised membrane patches. J Gen Physiol. 1982 Mar;79(3):333–351. doi: 10.1085/jgp.79.3.333. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Romey G., Jacques Y., Schweitz H., Fosset M., Lazdunski M. The sodium channel in non-impulsive cells. Interaction with specific neurotoxins. Biochim Biophys Acta. 1979 Sep 21;556(2):344–353. doi: 10.1016/0005-2736(79)90053-1. [DOI] [PubMed] [Google Scholar]
- 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]
- Sigworth F. J., Spalding B. C. Chemical modification reduces the conductance of sodium channels in nerve. Nature. 1980 Jan 17;283(5744):293–295. doi: 10.1038/283293a0. [DOI] [PubMed] [Google Scholar]