Skip to main content
NCBI home page
The Journal of General Physiology logoLink to The Journal of General Physiology
. 1991 Mar 1;97(3):499–519. doi: 10.1085/jgp.97.3.499

BTX modification of Na channels in squid axons. I. State dependence of BTX action

PMCID: PMC2216482  PMID: 1645393

Abstract

The state dependence of Na channel modification by batrachotoxin (BTX) was investigated in voltage-clamped and internally perfused squid giant axons before (control axons) and after the pharmacological removal of the fast inactivation by pronase, chloramine-T, or NBA (pretreated axons). In control axons, in the presence of 2-5 microM BTX, a repetitive depolarization to open the channels was required to achieve a complete BTX modification, characterized by the suppression of the fast inactivation and a simultaneous 50-mV shift of the activation voltage dependence in the hyperpolarizing direction, whereas a single long-lasting (10 min) depolarization to +50 mV could promote the modification of only a small fraction of the channels, the noninactivating ones. In pretreated axons, such a single sustained depolarization as well as the repetitive depolarization could induce a complete modification, as evidenced by a similar shift of the activation voltage dependence. Therefore, the fast inactivated channels were not modified by BTX. We compared the rate of BTX modification of the open and slow inactivated channels in control and pretreated axons using different protocols: (a) During a repetitive depolarization with either 4- or 100-ms conditioning pulses to +80 mV, all the channels were modified in the open state in control axons as well as in pretreated axons, with a similar time constant of approximately 1.2 s. (b) In pronase-treated axons, when all the channels were in the slow inactivated state before BTX application, BTX could modify all the channels, but at a very slow rate, with a time constant of approximately 9.5 min. We conclude that at the macroscopic level BTX modification can occur through two different pathways: (a) via the open state, and (b) via the slow inactivated state of the channels that lack the fast inactivation, spontaneously or pharmacologically, but at a rate approximately 500-fold slower than through the main open channel pathway.

Full Text

The Full Text of this article is available as a PDF (1.6 MB).

Selected References

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

  1. 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]
  2. Albuquerque E. X., Warnick J. E., Sansone F. M. The pharmacology of batrachotoxin. II. Effect on electrical properties of the mammalian nerve and skeletal muscle membranes. J Pharmacol Exp Ther. 1971 Mar;176(3):511–528. [PubMed] [Google Scholar]
  3. Armstrong C. M., Bezanilla F. Charge movement associated with the opening and closing of the activation gates of the Na channels. J Gen Physiol. 1974 May;63(5):533–552. doi: 10.1085/jgp.63.5.533. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Armstrong C. M., Bezanilla F., Rojas E. Destruction of sodium conductance inactivation in squid axons perfused with pronase. J Gen Physiol. 1973 Oct;62(4):375–391. doi: 10.1085/jgp.62.4.375. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. BAKER P. F., HODGKIN A. L., SHAW T. I. Replacement of the protoplasm of a giant nerve fibre with artificial solutions. Nature. 1961 Jun 3;190:885–887. doi: 10.1038/190885a0. [DOI] [PubMed] [Google Scholar]
  6. Barnes S., Hille B. Veratridine modifies open sodium channels. J Gen Physiol. 1988 Mar;91(3):421–443. doi: 10.1085/jgp.91.3.421. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Bartels-Bernal E., Rosenberry T. L., Daly J. W. Effect of batrachotoxin on the electroplax of electric eel: evidence for voltage-dependent interaction with sodium channels. Proc Natl Acad Sci U S A. 1977 Mar;74(3):951–955. doi: 10.1073/pnas.74.3.951. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Bezanilla F., Armstrong C. M. Inactivation of the sodium channel. I. Sodium current experiments. J Gen Physiol. 1977 Nov;70(5):549–566. doi: 10.1085/jgp.70.5.549. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Catterall W. A. Inhibition of voltage-sensitive sodium channels in neuroblastoma cells by antiarrhythmic drugs. Mol Pharmacol. 1981 Sep;20(2):356–362. [PubMed] [Google Scholar]
  10. 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]
  11. 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]
  12. Creveling C. R., McNeal E. T., Daly J. W., Brown G. B. Batrachotoxin-induced depolarization and [3H]batrachotoxinin-a 20 alpha-benzoate binding in a vesicular preparation from guinea pig cerebral cortex. Mol Pharmacol. 1983 Mar;23(2):350–358. [PubMed] [Google Scholar]
  13. 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]
  14. Hille B., Leibowitz M. D., Sutro J. B., Schwarz J. R., Holan G. State-dependent modification of sodium channels by lipid-soluble agonists. Soc Gen Physiol Ser. 1987;41:109–124. [PubMed] [Google Scholar]
  15. Hille B. Local anesthetics: hydrophilic and hydrophobic pathways for the drug-receptor reaction. J Gen Physiol. 1977 Apr;69(4):497–515. doi: 10.1085/jgp.69.4.497. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Hogan P. M., Albuquerque E. X. The pharmacology of batrachotoxin. 3. Effect on the heart Purkinje fibers. J Pharmacol Exp Ther. 1971 Mar;176(3):529–537. [PubMed] [Google Scholar]
  17. Horn R., Vandenberg C. A., Lange K. Statistical analysis of single sodium channels. Effects of N-bromoacetamide. Biophys J. 1984 Jan;45(1):323–335. doi: 10.1016/S0006-3495(84)84158-2. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Huang J. M., Tanguy J., Yeh J. Z. Removal of sodium inactivation and block of sodium channels by chloramine-T in crayfish and squid giant axons. Biophys J. 1987 Aug;52(2):155–163. doi: 10.1016/S0006-3495(87)83203-4. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Huang L. Y., Ehrenstein G., Catterall W. A. Interaction between batrachotoxin and yohimbine. Biophys J. 1978 Aug;23(2):219–231. doi: 10.1016/S0006-3495(78)85444-7. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. 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]
  21. Huang L. Y., Yatani A., Brown A. M. The properties of batrachotoxin-modified cardiac Na channels, including state-dependent block by tetrodotoxin. J Gen Physiol. 1987 Sep;90(3):341–360. doi: 10.1085/jgp.90.3.341. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Khodorov B. I. Batrachotoxin as a tool to study voltage-sensitive sodium channels of excitable membranes. Prog Biophys Mol Biol. 1985;45(2):57–148. doi: 10.1016/0079-6107(85)90005-7. [DOI] [PubMed] [Google Scholar]
  23. 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]
  24. Leibowitz M. D., Schwarz J. R., Holan G., Hille B. Electrophysiological comparison of insecticide and alkaloid agonists of Na channels. J Gen Physiol. 1987 Jul;90(1):75–93. doi: 10.1085/jgp.90.1.75. [DOI] [PMC free article] [PubMed] [Google Scholar]
  25. Leibowitz M. D., Sutro J. B., Hille B. Voltage-dependent gating of veratridine-modified Na channels. J Gen Physiol. 1986 Jan;87(1):25–46. doi: 10.1085/jgp.87.1.25. [DOI] [PMC free article] [PubMed] [Google Scholar]
  26. 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]
  27. Oxford G. S. Some kinetic and steady-state properties of sodium channels after removal of inactivation. J Gen Physiol. 1981 Jan;77(1):1–22. doi: 10.1085/jgp.77.1.1. [DOI] [PMC free article] [PubMed] [Google Scholar]
  28. Oxford G. S., Wu C. H., Narahashi T. Removal of sodium channel inactivation in squid giant axons by n-bromoacetamide. J Gen Physiol. 1978 Mar;71(3):227–247. doi: 10.1085/jgp.71.3.227. [DOI] [PMC free article] [PubMed] [Google Scholar]
  29. Oxford G. S., Yeh J. Z. Interactions of monovalent cations with sodium channels in squid axon. I. Modification of physiological inactivation gating. J Gen Physiol. 1985 Apr;85(4):583–602. doi: 10.1085/jgp.85.4.583. [DOI] [PMC free article] [PubMed] [Google Scholar]
  30. Patlak J. B., Ortiz M. Kinetic diversity of Na+ channel bursts in frog skeletal muscle. J Gen Physiol. 1989 Aug;94(2):279–301. doi: 10.1085/jgp.94.2.279. [DOI] [PMC free article] [PubMed] [Google Scholar]
  31. Patlak J. B., Ortiz M. Two modes of gating during late Na+ channel currents in frog sartorius muscle. J Gen Physiol. 1986 Feb;87(2):305–326. doi: 10.1085/jgp.87.2.305. [DOI] [PMC free article] [PubMed] [Google Scholar]
  32. 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]
  33. Quandt F. N. Burst kinetics of sodium channels which lack fast inactivation in mouse neuroblastoma cells. J Physiol. 1987 Nov;392:563–585. doi: 10.1113/jphysiol.1987.sp016797. [DOI] [PMC free article] [PubMed] [Google Scholar]
  34. Quandt F. N., Narahashi T. Modification of single Na+ channels by batrachotoxin. Proc Natl Acad Sci U S A. 1982 Nov;79(21):6732–6736. doi: 10.1073/pnas.79.21.6732. [DOI] [PMC free article] [PubMed] [Google Scholar]
  35. Rando T. A. Rapid and slow gating of veratridine-modified sodium channels in frog myelinated nerve. J Gen Physiol. 1989 Jan;93(1):43–65. doi: 10.1085/jgp.93.1.43. [DOI] [PMC free article] [PubMed] [Google Scholar]
  36. Rudy B. Slow inactivation of the sodium conductance in squid giant axons. Pronase resistance. J Physiol. 1978 Oct;283:1–21. doi: 10.1113/jphysiol.1978.sp012485. [DOI] [PMC free article] [PubMed] [Google Scholar]
  37. Shoukimas J. J., French R. J. Incomplete inactivation of sodium currents in nonperfused squid axon. Biophys J. 1980 Nov;32(2):857–862. doi: 10.1016/S0006-3495(80)85021-1. [DOI] [PMC free article] [PubMed] [Google Scholar]
  38. Stimers J. R., Bezanilla F., Taylor R. E. Sodium channel activation in the squid giant axon. Steady state properties. J Gen Physiol. 1985 Jan;85(1):65–82. doi: 10.1085/jgp.85.1.65. [DOI] [PMC free article] [PubMed] [Google Scholar]
  39. Sutro J. B. Kinetics of veratridine action on Na channels of skeletal muscle. J Gen Physiol. 1986 Jan;87(1):1–24. doi: 10.1085/jgp.87.1.1. [DOI] [PMC free article] [PubMed] [Google Scholar]
  40. Tamkun M. M., Catterall W. A. Ion flux studies of voltage-sensitive sodium channels in synaptic nerve-ending particles. Mol Pharmacol. 1981 Jan;19(1):78–86. [PubMed] [Google Scholar]
  41. Tanguy J., Yeh J. Z. Batrachotoxin uncouples gating charge immobilization from fast Na inactivation in squid giant axons. Biophys J. 1988 Oct;54(4):719–730. doi: 10.1016/S0006-3495(88)83007-8. [DOI] [PMC free article] [PubMed] [Google Scholar]
  42. Ulbricht W. The effect of veratridine on excitable membranes of nerve and muscle. Ergeb Physiol. 1969;61:18–71. doi: 10.1007/BFb0111446. [DOI] [PubMed] [Google Scholar]
  43. Wang G. K., Brodwick M. S., Eaton D. C. Removal of sodium channel inactivation in squid axon by the oxidant chloramine-T. J Gen Physiol. 1985 Aug;86(2):289–302. doi: 10.1085/jgp.86.2.289. [DOI] [PMC free article] [PubMed] [Google Scholar]
  44. Warnick J. E., Albuquerque E. X., Sansone F. M. The pharmacology of batrachotoxin. I. Effects on the contractile mechanism and on neuromuscular transmission of mammalian skeletal muscle. J Pharmacol Exp Ther. 1971 Mar;176(3):497–510. [PubMed] [Google Scholar]
  45. Willow M., Catterall W. A. Inhibition of binding of [3H]batrachotoxinin A 20-alpha-benzoate to sodium channels by the anticonvulsant drugs diphenylhydantoin and carbamazepine. Mol Pharmacol. 1982 Nov;22(3):627–635. [PubMed] [Google Scholar]
  46. Yamamoto D., Yeh J. Z., Narahashi T. Interactions of permeant cations with sodium channels of squid axon membranes. Biophys J. 1985 Sep;48(3):361–368. doi: 10.1016/S0006-3495(85)83792-9. [DOI] [PMC free article] [PubMed] [Google Scholar]

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

RESOURCES