N-Ethylmaleimide modulation of tetrodotoxin-sensitive and tetrodotoxin-resistant sodium channels in rat dorsal root ganglion neurons

Jin Ho Song, Yoon Young Jang, Yong Kyoo Shin, Chung Soo Lee, Sungkwon Chung

Research output: Contribution to journalArticle

Abstract

The effects of N-ethylmaleimide (NEM), an alkylating reagent to protein sulfhydryl groups, on tetrodotoxin-sensitive (TTX-S) and tetrodotoxin-resistant (TTX-R) sodium channels in rat dorsal root ganglion (DRG) neurons were studied using the whole cell configuration of patch-clamp technique. When currents were evoked by step depolarizations to 0 mV from a holding potential of -80 mV NEM decreased the amplitude of TTX-S sodium current, but exerted little or no effect on that of TTX-R sodium current. The inhibitory effect of NEM on TTX-S sodium channel was mainly due to the shift of the steady-state inactivation curve in the hyperpolarizing direction. NEM did not affect the voltage-dependence of the activation of TTX-S sodium channel. The steady-state inactivation curve for TTX-R sodium channel was shifted by NEM in the hyperpolarizing direction as that for TTX-S sodium channel. NEM caused a change in the voltage-dependence of the activation of TTX-R sodium channel unlike TTX-S sodium channel. After NEM treatment, the amplitudes of TTX-R sodium currents at test voltages below -10 mV were increased, but those at more positive voltages were not affected. This was explained by the shift in the conductance-voltage curve for TTX-R sodium channels in the hyperpolarizing direction after NEM treatment. Copyright (C) 2000 Elsevier Science B.V.

Original languageEnglish (US)
Pages (from-to)267-273
Number of pages7
JournalBrain research
Volume855
Issue number2
DOIs
StatePublished - Feb 14 2000
Externally publishedYes

Keywords

  • Alkylation
  • Dorsal root ganglion
  • N-Ethylmaleimide
  • Sodium channel
  • Sulfhydryl
  • Tetrodotoxin-resistant
  • Tetrodotoxin-sensitive

ASJC Scopus subject areas

  • Neuroscience(all)
  • Molecular Biology
  • Clinical Neurology
  • Developmental Biology

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