Effect of various cations and anions on the action of tetrodotoxin and saxitoxin on frog myelinated nerve fibers
- PMID: 6335243
- DOI: 10.1007/BF00583935
Effect of various cations and anions on the action of tetrodotoxin and saxitoxin on frog myelinated nerve fibers
Abstract
The influence of Mg2+, La3+, NO-3, and SCN- on the equilibrium effect of tetrodotoxin (TTX) and saxitoxin (STX) on single myelinated nerve fibres of the frog Rana esculenta was studied under voltage clamp conditions. Mg2+ and La3+ reduce the sodium permeability, shift the voltage dependence of the Na permeability PNa towards more positive potentials and reduce the effectiveness of TTX and STX. NO-3 and SCN- reduce the sodium permeability too, but shift the voltage dependence of PNa towards more negative potentials and increase the action of TTX and STX. In all experiments the change in effectiveness is larger for the divalent STX than for the monovalent TTX. It is concluded that changes of the monovalent TTX. It is concluded that changes of the external surface potential induced by Mg2+, La3+, NO-3 and SCN- affect the TTX and STX binding to toxin receptors. The apparent potential change at the toxin receptor is only a fraction of the change "seen' by the Na channel gates.
Similar articles
-
Use-dependent block with tetrodotoxin and saxitoxin at frog Ranvier nodes. II. Extrinsic influence of cations.Eur Biophys J. 1991;20(3):143-9. doi: 10.1007/BF01561136. Eur Biophys J. 1991. PMID: 1660396
-
Effects of deuterium oxide on the rate and dissociation constants for saxitoxin and tetrodotoxin action. Voltage-clamp studies on frog myelinated nerve.J Gen Physiol. 1981 Aug;78(2):113-39. doi: 10.1085/jgp.78.2.113. J Gen Physiol. 1981. PMID: 6268735 Free PMC article.
-
Use-dependent block of sodium channels in frog myelinated nerve by tetrodotoxin and saxitoxin at negative holding potentials.Biochim Biophys Acta. 1989 Oct 16;985(2):153-60. doi: 10.1016/0005-2736(89)90360-x. Biochim Biophys Acta. 1989. PMID: 2553115
-
A pharmacological approach to the structure of sodium channels in myelinated axons.Annu Rev Neurosci. 1979;2:341-62. doi: 10.1146/annurev.ne.02.030179.002013. Annu Rev Neurosci. 1979. PMID: 395883 Review.
-
An integrated view of the molecular toxinology of sodium channel gating in excitable cells.Annu Rev Neurosci. 1987;10:237-67. doi: 10.1146/annurev.ne.10.030187.001321. Annu Rev Neurosci. 1987. PMID: 2436544 Review.
Cited by
-
Divalent ion trapping inside potassium channels of human T lymphocytes.J Gen Physiol. 1989 Apr;93(4):609-30. doi: 10.1085/jgp.93.4.609. J Gen Physiol. 1989. PMID: 2786551 Free PMC article.
-
Magnesium sulfate diminishes the effects of amide local anesthetics in rat sciatic-nerve block.Reg Anesth Pain Med. 2007 Jul-Aug;32(4):288-95. doi: 10.1016/j.rapm.2007.03.008. Reg Anesth Pain Med. 2007. PMID: 17720112 Free PMC article.
-
Competitive binding interaction between Zn2+ and saxitoxin in cardiac Na+ channels. Evidence for a sulfhydryl group in the Zn2+/saxitoxin binding site.Biophys J. 1991 Mar;59(3):523-37. doi: 10.1016/S0006-3495(91)82269-X. Biophys J. 1991. PMID: 1646656 Free PMC article.
-
Influence of negative surface charge on toxin binding to canine heart Na channels in planar bilayers.Biophys J. 1989 Feb;55(2):359-65. doi: 10.1016/S0006-3495(89)82813-9. Biophys J. 1989. PMID: 2540849 Free PMC article.