Differences in action potentials and accommodation of sensory and motor myelinated nerve fibres as computed on the basis of voltage clamp data

1975 ◽  
Vol 354 (3) ◽  
pp. 257-271 ◽  
Author(s):  
A. H. Bretag ◽  
R. St�mpfli
Keyword(s):  
Voltage Clamp ◽  
Action Potentials ◽  
Nerve Fibres ◽  
Myelinated Nerve

Oscillating repolarization in action potentials of frog sensory myelinated nerve fibres

1983 ◽  
Vol 36 (1) ◽  
pp. 49-53 ◽  
Author(s):  
Rolf P. Spielmann ◽  
Jürgen R. Schwarz ◽  
Burkhart Bromm
Keyword(s):  
Action Potentials ◽  
Nerve Fibres ◽  
Myelinated Nerve

scholarly journals Effects of deuterium oxide on the rate and dissociation constants for saxitoxin and tetrodotoxin action. Voltage-clamp studies on frog myelinated nerve.

1981 ◽  
Vol 78 (2) ◽  
pp. 113-139 ◽  
Author(s):  
R Hahin ◽  
G Strichartz
Keyword(s):  
Steady State ◽  
Sodium Channel ◽  
Voltage Clamp ◽  
Action Potentials ◽  
Dissociation Constants ◽  
Deuterium Oxide ◽  
Hydrogen Binding ◽  
Myelinated Nerve ◽  
Normal Water ◽  
Isotopic Effects

The actions of tetrodotoxin (TTX) and saxitoxin (STX) in normal water and in deuterium oxide (D2O) have been studied in frog myelinated nerve. Substitution of D2O for H2O in normal Ringer's solution has no effect on the potency of TTX in blocking action potentials but increases the potency of STX by approximately 50%. Under voltage clamp, the steady-state inhibition of sodium currents by 1 nM STX is doubled in D2O as a result of a halving of the rate of dissociation of STX from the sodium channel; the rate of block by STX is not measurably changed by D2O. Neither steady-state inhibition nor the on- or off-rate constants of TTX are changed by D2O substitution. The isotopic effects on STX binding are observed less than 10 min after the toxin has been added to D2O, thus eliminating the possibility that slow-exchange (t 1/2 greater than 10 h) hydrogen-binding sites on STX are involved. The results are consistent with a hypothesis that attributes receptor-toxin stabilization to isotopic changes of hydrogen bonding; this interpretation suggests that hydrogen bonds contribute more to the binding of STX than to that of TTX at the sodium channel.

Sign in / Sign up

Export Citation Format

Share Document