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 language | English (US) |
|---|---|
| Pages (from-to) | 909-920 |
| Number of pages | 12 |
| Journal | Neurotoxicology |
| Volume | 20 |
| Issue number | 6 |
| State | Published - 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