ArticleBiophysical journal2003
Tonic and phasic guanidinium toxin-block of skeletal muscle Na channels expressed in Mammalian cells.
Article in Biophysical journal, 2003. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 11 papers.
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Who cites it
11 citing papers in PubMed, 27 citations in OpenAlex.
- Functional effects of drugs and toxins interacting with NaFrontiers in pharmacology · 2024Review
- Trifunctional Saxitoxin Conjugates for Covalent Labeling of Voltage-Gated Sodium Channels.Chembiochem : a European journal of chemical biology · 2023Article
- Differential effects of modified batrachotoxins on voltage-gated sodium channel fast and slow inactivation.Cell chemical biology · 2022Article
- Mutant cycle analysis with modified saxitoxins reveals specific interactions critical to attaining high-affinity inhibition of hNaV1.7.Proceedings of the National Academy of Sciences of the United States of America · 2016Article
- Sodium channel diversity in the vestibular ganglion: NaV1.5, NaV1.8, and tetrodotoxin-sensitive currents.Journal of neurophysiology · 2016Article
- Review
- Marked difference in saxitoxin and tetrodotoxin affinity for the human nociceptive voltage-gated sodium channel (Nav1.7) [corrected].Proceedings of the National Academy of Sciences of the United States of America · 2012Article
- Use-dependent block of the voltage-gated Na(+) channel by tetrodotoxin and saxitoxin: effect of pore mutations that change ionic selectivity.The Journal of general physiology · 2012Article
- The outer vestibule of the Na+ channel-toxin receptor and modulator of permeation as well as gating.Marine drugs · 2010Review
- De novo synthesis of modified saxitoxins for sodium ion channel study.Journal of the American Chemical Society · 2009Article
- Beta1-subunit modulates the Nav1.4 sodium channel by changing the surface charge.Experimental brain research · 2006Article
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Authors and funding
3 authors at 1 institution in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
The blockage of skeletal muscle sodium channels by tetrodotoxin (TTX) and saxitoxin (STX) have been studied in CHO cells permanently expressing rat Nav1.4 channels. Tonic and use-dependent blockage were analyzed in the framework of the ion-trapped model. The tonic affinity (26.6 nM) and the maximum affinity (7.7 nM) of TTX, as well as the "on" and "off" rate constants measured in this preparation, are in remarkably good agreement with those measured for Nav1.2 expressed in frog oocytes, indicating that the structure of the toxin receptor of Nav1.4 and Nav1.2 channels are very similar and that the expression method does not have any influence on the pore properties of the sodium channel. The higher affinity of STX for the sodium channels (tonic and maximum affinity of 1.8 nM and 0.74 nM respectively) is explained as an increase on the "on" rate constant (approximately 0.03 s(-1) nM(-1)), compared to that of TTX (approximately 0.003 s(-1) nM(-1)), while the "off" rate constant is the same for both toxins (approximately 0.02 s(-1)). Estimations of the free-energy differences of the toxin-channel interaction indicate that STX is bound in a more external position than TTX. Similarly, the comparison of the toxins free energy of binding to a ion-free, Na(+)- and Ca(2+)-occupied channel, is consistent with a binding site in the selectivity filter for Ca(2+) more external than for Na(+). This data may be useful in further attempts at sodium-channel pore modeling.
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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.