Biophysical costs associated with tetrodotoxin resistance in the sodium channel pore of the garter snake, Thamnophis sirtalis

Chong Hyun Lee; David K Jones; Christopher Ahern; Maen F Sarhan; Peter C Ruben

doi:10.1007/s00359-010-0582-9

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Biophysical costs associated with tetrodotoxin resistance in the sodium channel pore of the garter snake, Thamnophis sirtalis

Journal article

Peer reviewed

Biophysical costs associated with tetrodotoxin resistance in the sodium channel pore of the garter snake, Thamnophis sirtalis

Chong Hyun Lee, David K Jones, Christopher Ahern, Maen F Sarhan and Peter C Ruben

Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology, Vol.197(1), pp.33-43

01/2011

DOI: 10.1007/s00359-010-0582-9

PMID: 20820785

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Abstract

Tetrodotoxin (TTX) is a potent toxin that specifically binds to voltage-gated sodium channels (NaV). TTX binding physically blocks the flow of sodium ions through NaV, thereby preventing action potential generation and propagation. TTX has different binding affinities for different NaV isoforms. These differences are imparted by amino acid substitutions in positions within, or proximal to, the TTX-binding site in the channel pore. These substitutions confer TTX-resistance to a variety of species. The garter snake Thamnophis sirtalis has evolved TTX-resistance over the course of an arms race, allowing some populations of snakes to feed on tetrodotoxic newts, including Taricha granulosa. Different populations of the garter snake have different degrees of TTX-resistance, which is closely related to the number of amino acid substitutions. We tested the biophysical properties and ion selectivity of NaV of three garter snake populations from Bear Lake, Idaho; Warrenton, Oregon; and Willow Creek, California. We observed changes in gating properties of TTX-resistant (TTXr) NaV. In addition, ion selectivity of TTXr NaV was significantly different from that of TTX-sensitive NaV. These results suggest TTX-resistance comes at a cost to performance caused by changes in the biophysical properties and ion selectivity of TTXr NaV.

Membrane Potentials - drug effects

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Membrane Potentials - genetics

Humans

Microinjections - methods

Biophysical Phenomena - drug effects

NAV1.4 Voltage-Gated Sodium Channel

Sodium Channel Blockers - pharmacology

Colubridae - metabolism

Patch-Clamp Techniques - methods

Muscle Proteins - genetics

Animals

Ion Channel Gating - genetics

Muscle Proteins - metabolism

Sodium Channels - metabolism

Biophysical Phenomena - genetics

Sodium Channel Blockers - chemistry

Sodium Channels - genetics

Tetrodotoxin - pharmacology

Biophysics - methods

Electric Stimulation - methods

Oocysts

Tetrodotoxin - chemistry

Ion Channel Gating - drug effects

Details

Title: Subtitle: Biophysical costs associated with tetrodotoxin resistance in the sodium channel pore of the garter snake, Thamnophis sirtalis
Creators: Chong Hyun Lee - Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada. paull@sfu.ca
David K Jones
Christopher Ahern
Maen F Sarhan
Peter C Ruben
Resource Type: Journal article
Publication Details: Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology, Vol.197(1), pp.33-43
Publisher: Germany
DOI: 10.1007/s00359-010-0582-9
PMID: 20820785
ISSN: 0340-7594
eISSN: 1432-1351
Language: English
Date published: 01/2011
Academic Unit: Molecular Physiology and Biophysics; Iowa Neuroscience Institute
Record Identifier: 9984070699302771

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