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. 1987 May;84(9):3051–3055. doi: 10.1073/pnas.84.9.3051

Site of anticonvulsant action on sodium channels: autoradiographic and electrophysiological studies in rat brain.

P F Worley, J M Baraban
PMCID: PMC304800  PMID: 2437590

Abstract

The anticonvulsants phenytoin and carbamazepine interact allosterically with the batrachotoxin binding site of sodium channels. In the present study, we demonstrate an autoradiographic technique to localize the batrachotoxin binding site on sodium channels in rat brain using [3H]batrachotoxinin-A 20-alpha-benzoate (BTX-B). Binding of [3H]BTX-B to brain sections is dependent on potentiating allosteric interactions with scorpion venom and is displaced by BTX-B (Kd approximately 200 nM), aconitine, veratridine, and phenytoin with the same rank order of potencies as described in brain synaptosomes. The maximum number of [3H]BTX-B binding sites in forebrain sections (approximately 1 pmol/mg of protein) also agrees with biochemical determinations. Autoradiographic localizations indicate that [3H]BTX-B binding sites are not restricted to cell bodies and axons but are present in synaptic zones throughout the brain. For example, a particularly dense concentration of these sites in the substantia nigra is associated with afferent terminals of the striatonigral projection. By contrast, myelinated structures possess much lower densities of binding sites. In addition, we present electrophysiological evidence that synaptic transmission, as opposed to axonal conduction, is preferentially sensitive to the action of aconitine and veratridine. Finally, the synaptic block produced by these sodium channel activators is inhibited by phenytoin and carbamazepine at therapeutic anticonvulsant concentrations. Thus, these anticonvulsants may limit seizure spread not only by affecting all-or-none conduction by axonal sodium channels but also by modulating graded aspects of synaptic transmission.

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Selected References

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  1. Alger B. E., Nicoll R. A. Feed-forward dendritic inhibition in rat hippocampal pyramidal cells studied in vitro. J Physiol. 1982 Jul;328:105–123. doi: 10.1113/jphysiol.1982.sp014255. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. 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]
  3. Benoit E., Corbier A., Dubois J. M. Evidence for two transient sodium currents in the frog node of Ranvier. J Physiol. 1985 Apr;361:339–360. doi: 10.1113/jphysiol.1985.sp015649. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Catterall W. A., Morrow C. S., Daly J. W., Brown G. B. Binding of batrachotoxinin A 20-alpha-benzoate to a receptor site associated with sodium channels in synaptic nerve ending particles. J Biol Chem. 1981 Sep 10;256(17):8922–8927. [PubMed] [Google Scholar]
  5. Chang C. C., Tseng K. H. Effect of crotamine, a toxin of South American rattlesnake venom, on the sodium channel of murine skeletal muscle. Br J Pharmacol. 1978 Jul;63(3):551–559. doi: 10.1111/j.1476-5381.1978.tb07811.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Connors B. W., Gutnick M. J., Prince D. A. Electrophysiological properties of neocortical neurons in vitro. J Neurophysiol. 1982 Dec;48(6):1302–1320. doi: 10.1152/jn.1982.48.6.1302. [DOI] [PubMed] [Google Scholar]
  7. 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]
  8. Gilly W. F., Armstrong C. M. Threshold channels--a novel type of sodium channel in squid giant axon. 1984 May 31-Jun 6Nature. 309(5967):448–450. doi: 10.1038/309448a0. [DOI] [PubMed] [Google Scholar]
  9. Hotson J. R., Prince D. A., Schwartzkroin P. A. Anomalous inward rectification in hippocampal neurons. J Neurophysiol. 1979 May;42(3):889–895. doi: 10.1152/jn.1979.42.3.889. [DOI] [PubMed] [Google Scholar]
  10. Johnston D., Hablitz J. J., Wilson W. A. Voltage clamp discloses slow inward current in hippocampal burst-firing neurones. Nature. 1980 Jul 24;286(5771):391–393. doi: 10.1038/286391a0. [DOI] [PubMed] [Google Scholar]
  11. Llinás R., Sugimori M. Electrophysiological properties of in vitro Purkinje cell somata in mammalian cerebellar slices. J Physiol. 1980 Aug;305:171–195. doi: 10.1113/jphysiol.1980.sp013357. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Macdonald R. L., McLean M. J., Skerritt J. H. Anticonvulsant drug mechanisms of action. Fed Proc. 1985 Jul;44(10):2634–2639. [PubMed] [Google Scholar]
  13. Marangos P. J., Post R. M., Patel J., Zander K., Parma A., Weiss S. Specific and potent interactions of carbamazepine with brain adenosine receptors. Eur J Pharmacol. 1983 Sep 30;93(3-4):175–182. doi: 10.1016/0014-2999(83)90135-8. [DOI] [PubMed] [Google Scholar]
  14. Masuda Y., Utsui Y., Shiraishi Y., Karasawa T., Yoshida K., Shimizu M. Relationships between plasma concentrations of diphenylhydantoin, phenobarbital, carbamazepine, and 3-sulfamoylmethyl-1,2-benzisoxazole (AD-810), a new anticonvulsant agent, and their anticonvulsant or neurotoxic effects in experimental animals. Epilepsia. 1979 Dec;20(6):623–633. doi: 10.1111/j.1528-1157.1979.tb04846.x. [DOI] [PubMed] [Google Scholar]
  15. Matsuki N., Quandt F. N., Ten Eick R. E., Yeh J. Z. Characterization of the block of sodium channels by phenytoin in mouse neuroblastoma cells. J Pharmacol Exp Ther. 1984 Feb;228(2):523–530. [PubMed] [Google Scholar]
  16. McLean M. J., Macdonald R. L. Multiple actions of phenytoin on mouse spinal cord neurons in cell culture. J Pharmacol Exp Ther. 1983 Dec;227(3):779–789. [PubMed] [Google Scholar]
  17. Mourre C., Lombet A., Lazdunski M. Autoradiographic localization of tetrodotoxin-sensitive Na+ channels in rat brain. Neurosci Lett. 1984 Nov 23;52(1-2):31–35. doi: 10.1016/0304-3940(84)90346-x. [DOI] [PubMed] [Google Scholar]
  18. Nicoll R. A., Alger B. E. A simple chamber for recording from submerged brain slices. J Neurosci Methods. 1981 Aug;4(2):153–156. doi: 10.1016/0165-0270(81)90049-2. [DOI] [PubMed] [Google Scholar]
  19. Noda M., Ikeda T., Kayano T., Suzuki H., Takeshima H., Kurasaki M., Takahashi H., Numa S. Existence of distinct sodium channel messenger RNAs in rat brain. Nature. 1986 Mar 13;320(6058):188–192. doi: 10.1038/320188a0. [DOI] [PubMed] [Google Scholar]
  20. Ohizumi Y., Nakamura H., Kobayashi J., Catterall W. A. Specific inhibition of [3H] saxitoxin binding to skeletal muscle sodium channels by geographutoxin II, a polypeptide channel blocker. J Biol Chem. 1986 May 15;261(14):6149–6152. [PubMed] [Google Scholar]
  21. Olpe H. R., Baudry M., Jones R. S. Electrophysiological and neurochemical investigations on the action of carbamazepine on the rat hippocampus. Eur J Pharmacol. 1985 Mar 26;110(1):71–80. doi: 10.1016/0014-2999(85)90030-5. [DOI] [PubMed] [Google Scholar]
  22. Post R. M., Uhde T. W., Rubinow D. R., Ballenger J. C., Gold P. W. Biochemical effects of carbamazepine: relationship to its mechanisms of action in affective illness. Prog Neuropsychopharmacol Biol Psychiatry. 1983;7(2-3):263–271. doi: 10.1016/0278-5846(83)90116-1. [DOI] [PubMed] [Google Scholar]
  23. Rando T. A., Wang G. K., Strichartz G. R. The interaction between the activator agents batrachotoxin and veratridine and the gating processes of neuronal sodium channels. Mol Pharmacol. 1986 May;29(5):467–477. [PubMed] [Google Scholar]
  24. Schneiderman J. H., Schwartzkroin P. A. Effects of phenytoin on normal activity and on penicillin-induced bursting in the guinea pig hippocampal slice. Neurology. 1982 Jul;32(7):730–738. doi: 10.1212/wnl.32.7.730. [DOI] [PubMed] [Google Scholar]
  25. Stafstrom C. E., Schwindt P. C., Crill W. E. Negative slope conductance due to a persistent subthreshold sodium current in cat neocortical neurons in vitro. Brain Res. 1982 Mar 18;236(1):221–226. doi: 10.1016/0006-8993(82)90050-6. [DOI] [PubMed] [Google Scholar]
  26. 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]
  27. Willow M., Gonoi T., Catterall W. A. Voltage clamp analysis of the inhibitory actions of diphenylhydantoin and carbamazepine on voltage-sensitive sodium channels in neuroblastoma cells. Mol Pharmacol. 1985 May;27(5):549–558. [PubMed] [Google Scholar]
  28. Willow M., Kuenzel E. A., Catterall W. A. Inhibition of voltage-sensitive sodium channels in neuroblastoma cells and synaptosomes by the anticonvulsant drugs diphenylhydantoin and carbamazepine. Mol Pharmacol. 1984 Mar;25(2):228–234. [PubMed] [Google Scholar]
  29. Wollner D. A., Catterall W. A. Antigenic differences among the voltage-sensitive sodium channels in the peripheral and central nervous systems and skeletal muscle. Brain Res. 1985 Apr 1;331(1):145–149. doi: 10.1016/0006-8993(85)90724-3. [DOI] [PubMed] [Google Scholar]
  30. Worley P. F., Baraban J. M., Snyder S. H. Heterogeneous localization of protein kinase C in rat brain: autoradiographic analysis of phorbol ester receptor binding. J Neurosci. 1986 Jan;6(1):199–207. doi: 10.1523/JNEUROSCI.06-01-00199.1986. [DOI] [PMC free article] [PubMed] [Google Scholar]
  31. Yaari Y., Selzer M. E., Pincus J. H. Phenytoin: mechanisms of its anticonvulsant action. Ann Neurol. 1986 Aug;20(2):171–184. doi: 10.1002/ana.410200202. [DOI] [PubMed] [Google Scholar]

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