Title

Ciguatoxin (CTX-1) modulates single tetrodotoxin-sensitive sodium channels in rat parasympathetic neurones

RIS ID

106118

Publication Details

Hogg, R. C., Lewis, R. J. & Adams, D. J. (1998). Ciguatoxin (CTX-1) modulates single tetrodotoxin-sensitive sodium channels in rat parasympathetic neurones. Neuroscience Letters, 252 (2), 103-106.

Abstract

The actions of the marine neurotoxin, ciguatoxin-1 (CTX-1), were investigated in isolated parasympathetic neurones from neonatal rat intracardiac ganglia using patch-clamp recording techniques. Under current clamp conditions, bath application of 1-10 nM CTX-1 caused gradual membrane depolarization and tonic action potential firing. Action potential firing ceased with depolarization beyond approximately -35 mV and application of 300 nM tedrodotoxin (TTX) repolarized the cell to its control resting potential. In cell-attached membrane patches, 1-10 nM CTX-1 in the patch pipette markedly increased the open probability of single TTX-sensitive Na+ channels in response to depolarizing voltage steps but did not alter the unitary conductance (10 pS) or reversal potential. Under steady-state conditions, CTX-1 caused spontaneous opening of single Na+ channels which did not inactivate at hyperpolarized membrane potentials. CTX-1 increases neuronal excitability by shifting the voltage of activation of TTX-sensitive Na+ channels to more negative potentials.

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Link to publisher version (DOI)

http://dx.doi.org/10.1016/S0304-3940(98)00575-8