Brevetoxin modulates neuronal sodium channels in two cell lines derived from rat brain

S. L. Purkerson, D. G. Baden, L. A. Fieber

Research output: Contribution to journalArticle

36 Scopus citations

Abstract

Single Na+ channel currents were recorded from cell-attached membrane patches from two neuronal cell lines derived from rat brain, B50 and B104, and compared before and after exposure of the cells to purified brevetoxin, PbTx-3. B50 and B104 Na+ channels usually exhibited fast activation and inactivation as is typical of TTX-sensitive Na+ channels. PbTx-3 modified channel gating in both cell lines. PbTx-3 caused (1) significant increases in the frequency of channel reopening, indicating a slowing of channel inactivation, (2) a change in the voltage dependence of the channels, promoting channel opening during steady-state voltage clamp of the membrane at voltages throughout the activation range of Na+ currents, but notably near the resting potential of these cells (-60 - -50 mV), and (3) a significant, 6.7 mV hyperpolarized shift in the threshold potential for channel opening. Na+ channel slope conductance did not change in PbTx-3- exposed B50 and B104 neurons. These effects of Pbx-3 may cause hyperexcitability as well as inhibitory effects in intact brain. (C) 1999 Intox Press, Inc.

Original languageEnglish (US)
Pages (from-to)909-920
Number of pages12
JournalNeurotoxicology
Volume20
Issue number6
StatePublished - Dec 1 1999

Keywords

  • Brevetoxin
  • Cell Lines
  • Na Channel
  • Neurotoxic Shellfish Poisoning
  • Patch Clamp
  • Single Channel

ASJC Scopus subject areas

  • Cellular and Molecular Neuroscience
  • Neuroscience(all)
  • Toxicology

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