Differential block of two types of sodium channels by anticonvulsants

Jin Ho Song, Keiichi Nagata, Chao Sheng Huang, Jay Z. Yeh, Toshio Narahashi*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

28 Scopus citations


THE differential effects of the anticonvulsants phenytoin and carbamazepine on the sodium channels of rat dorsal root ganglion (DRG) neurons were studied using the patch clamp technique. The action potentials from tetrodotoxin-resistant (TTX-R) cells were less sensitive to phenytoin and carbamazepine than those from tetrodotoxin-sensitive (TTX-S) cells. The steady-state inactivation curve for TTX-S sodium channels was shifted by as much as 20.6 mV and 11.4 mV by phenytoin and carbamazepine at 300 μM, respectively, yet the curve for TTX-R sodium channels was shifted only by 6.0 mV and 6.9 mV, respectively. Thus, the differential action potential block of TTX-S and TTX-R cells by phenytoin and carbamazepine is due to different voltage dependence of and differential drug effects on the inactivation kinetics of two types of sodium channels.

Original languageEnglish (US)
Pages (from-to)3031-3036
Number of pages6
Issue number18
StatePublished - 1996


  • Action potential
  • Carbamazepine
  • Diphenylhydantoin
  • Dorsal root ganglion
  • Phenytoin
  • Sodium channel
  • Tetrodotoxin-resistant
  • Tetrodotoxin-sensitive

ASJC Scopus subject areas

  • Neuroscience(all)

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