Rate of action of Anemonia sulcata toxin II on sodium channels in myelinated nerve fibres

Toxicon ◽  
1984 ◽  
Vol 22 (6) ◽  
pp. 989
Author(s):  
H.P. Kolm
Keyword(s):  
Sodium Channels ◽  
Nerve Fibres ◽  
Myelinated Nerve ◽  
Anemonia Sulcata

Rate of action ofAnemonia sulcata toxin II on sodium channels in myelinated nerve fibres

1982 ◽  
Vol 394 (4) ◽  
pp. 313-319 ◽  
Author(s):  
Johann Schmidtmayer ◽  
Mechthild Stoye-Herzog ◽  
Werner Ulbricht
Keyword(s):  
Sodium Channels ◽  
Nerve Fibres ◽  
Myelinated Nerve

Sodium and potassium channels in regenerating and developing mammalian myelinated nerves

1982 ◽  
Vol 215 (1200) ◽  
pp. 273-287 ◽  
Keyword(s):  
Potassium Channels ◽  
Action Potential ◽  
Sodium Channels ◽  
Unit Length ◽  
Nerve Fibres ◽  
Myelinated Nerve ◽  
Complementary Distribution ◽  
Myelinated Nerves ◽  
Sodium And Potassium ◽  
Regenerating Nerve

A study has been made of how the normal complementary distribution of sodium and potassium channels in mammalian myelinated nerve fibres (all the sodium channels being in the node with all the potassium channels in the internode) is altered in regenerating and in developing rabbit sciatic nerves. In regenerating nerve fibres, where a marked increase in the number of nodes per unit length occurs, there is a corresponding increase in the sodium channel content (determined from the maximum saturable binding of labelled saxitoxin), consistent with the idea that the number of sodium channels per node remains roughly constant. The use of 4-aminopyridine, which by blocking potassium channels prolongs the action potential, has shown that both in regenerating nerve fibres and in developing nerve fibres potassium currents contribute to the mammalian action potential. In both cases, with the passage of time, the sensitivity to 4-aminopyridine progressively decreases.

Binding of tetrodotoxin and saxitoxin to sodium channels

1975 ◽  
Vol 270 (908) ◽  
pp. 319-336 ◽  
Keyword(s):  
Sodium Channels ◽  
Specific Binding ◽  
Chemical Characterization ◽  
Nerve Fibres ◽  
Myelinated Nerve ◽  
Channel Density ◽  
Binding Curve ◽  
Measurable Property ◽  
Binding Component

A useful first step in any chemical characterization of the sodium channels in nerve membrane would clearly be the identification of some measurable property of the channel that does not depend on the intactness of the tissue. To this end, tetrodotoxin and saxitoxin, which bind specifically to sodium channels, have been tritiated and their binding to rabbit, lobster and garfish non-myelinated nerve fibres examined. In each case, a component of the binding curve was found that saturated at concen­ trations of a few nanomolar. In addition, non-specific binding, indicated by a linear dependence of the amount bound on concentration, occurred. A solubilized membrane preparation from garfish nerve shows the same specific binding component as that of the intact nerve. The saturable component of binding seems to reflect the sodium channel density in nerve, and this is extremely small, being about 27/m 2 in the rabbit nerve and as small as 6/jtfjtm 2 in the garfish nerve.

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