An improved voltage clamp for gating current recording from the squid giant axon

1995 ◽  
pp. 97-106
Author(s):  
Ian C. Forster ◽  
Nikolaus G. Greeff
Keyword(s):  
Voltage Clamp ◽  
Giant Axon ◽  
Squid Giant Axon ◽  
Gating Current

Conduction velocity and gating current in the squid giant axon

1975 ◽  
Vol 189 (1094) ◽  
pp. 81-86 ◽  
Keyword(s):  
Sodium Channel ◽  
Conduction Velocity ◽  
Charged Particles ◽  
Giant Axon ◽  
Squid Giant Axon ◽  
Gating Current ◽  
Giant Axons ◽  
Sodium Conductance ◽  
Conduction Velocities

As predicted by Hodgkin (1975), calculation of conduction velocities in squid giant axons shows that if each sodium channel is gated by charged particles moving in the membrane field there will be a maximum in the relation between sodium conductance and conduction velocity.

scholarly journals Sodium influxes in internally perfused squid giant axon during voltage clamp

1969 ◽  
Vol 201 (3) ◽  
pp. 657-664 ◽  
Author(s):  
I. Atwater ◽  
F. Bezanilla ◽  
E. Rojas
Keyword(s):  
Voltage Clamp ◽  
Giant Axon ◽  
Squid Giant Axon

The effect of displacement current on the measurement of reversal potential in squid giant axon

1982 ◽  
Vol 60 (12) ◽  
pp. 1541-1544 ◽  
Author(s):  
H. Wodlinger ◽  
H. Kunov ◽  
H. L. Atwood
Keyword(s):  
Voltage Clamp ◽  
Time Constant ◽  
Reversal Potential ◽  
Giant Axon ◽  
Squid Giant Axon ◽  
Displacement Current ◽  
Before And After

The measurement of the sodium reversal potential (Erev), as that potential where the early current reverses during voltage clamp, was found to exceed the true Erev by 4.1 ± 2.4 mV (mean ± SD) in squid giant axon. This error was found in both intact and internally perfused axons and is due to interference from the displacement current. This was shown by subtraction of the current records obtained before and after treatment with tetrodotoxin (TTX). The error in Erev is proportional to [Formula: see text] where Td is the time constant of the displacement current.

scholarly journals Time course of the sodium influx in squid giant axon during a single voltage clamp pulse

1970 ◽  
Vol 207 (1) ◽  
pp. 151-164 ◽  
Author(s):  
Francisco Bezanilla ◽  
Eduardo Rojas ◽  
Robert E. Taylor
Keyword(s):  
Voltage Clamp ◽  
Time Course ◽  
Giant Axon ◽  
Squid Giant Axon ◽  
Sodium Influx

scholarly journals THE EFFECT OF SODIUM AND POTASSIUM IONS ON THE IMPEDANCE CHANGE ACCOMPANYING THE SPIKE IN THE SQUID GIANT AXON

1953 ◽  
Vol 37 (1) ◽  
pp. 25-37 ◽  
Author(s):  
Harry Grundfest ◽  
Abraham M. Shanes ◽  
Walter Freygang
Keyword(s):  
Voltage Clamp ◽  
Potassium Level ◽  
Giant Axon ◽  
Sodium Concentration ◽  
Squid Giant Axon ◽  
Potassium Ions ◽  
Impedance Change ◽  
Voltage Clamp Technique ◽  
Sodium And Potassium ◽  
Identical Fashion

Decrease of the sodium concentration of the medium depresses both the spike and the associated impedance change in almost identical fashion. Elevation of the potassium level also depresses both phenomena, but affects the impedance change more than the spike; it slows the return to the initial impedance level. The effects on the threshold to brief square waves are also described. These results appear largely accounted for by the observations of Hodgkin and Huxley with the voltage clamp technique and by their recent hypothesis as to nature of the spike processes.

Kinetic analysis of the sodium gating current in the squid giant axon

1990 ◽  
Vol 240 (1299) ◽  
pp. 411-423 ◽  
Keyword(s):  
Giant Axon ◽  
Squid Giant Axon ◽  
Critical Study ◽  
Gating Current ◽  
Time Constants ◽  
Delayed Onset ◽  
Sodium System ◽  
Relaxation Time Constants ◽  
Fast Rise ◽  
Intermediate Rate

A critical study has been made of the characteristics of the kinetic components of the sodium gating current in the squid giant axon, of which not less than five can be resolved. In addition to the principal fast component I g 2 , there are two components of appreciable size that relax at an intermediate rate, I g 3a and I g 3b , I g 3a has a fast rise, and is present over the whole range of negative test potentials. I g 3b absent below -40 mV, exhibits a delayed onset and disappears on inactivation of the sodium system. There are also two smaller components, I g 1 and I g 4 , with very fast and much slower relaxation time constants, respectively.

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