scholarly journals Some effects of aliphatic hydrocarbons on the electrical capacity and ionic currents of the squid giant axon membrane.

1980 ◽  
Vol 309 (1) ◽  
pp. 229-245 ◽  
Author(s):  
D A Haydon ◽  
J Requena ◽  
B W Urban
Keyword(s):  
Ionic Currents ◽  
Giant Axon ◽  
Squid Giant Axon ◽  
Aliphatic Hydrocarbons ◽  
Axon Membrane ◽  
Electrical Capacity

scholarly journals Effect of Temperature on the Potential and Current Thresholds of Axon Membrane

1962 ◽  
Vol 46 (2) ◽  
pp. 257-266 ◽  
Author(s):  
Rita Guttman ◽  
Keyword(s):  
Sea Water ◽  
Sucrose Solution ◽  
Giant Axon ◽  
Threshold Current ◽  
Squid Giant Axon ◽  
Effect Of Temperature ◽  
Threshold Potential ◽  
Axon Membrane ◽  
Central Segment ◽  
The Mean

The effect of temperature on the potential and current thresholds of the squid giant axon membrane was measured with gross external electrodes. A central segment of the axon, 0.8 mm long and in sea water, was isolated by flowing low conductance, isoosmotic sucrose solution on each side; both ends were depolarized in isoosmotic KCl. Measured biphasic square wave currents at five cycles per second were applied between one end of the nerve and the membrane of the central segment. The membrane potential was recorded between the central sea water and the other depolarized end. The recorded potentials are developed only across the membrane impedance. Threshold current values ranged from 3.2 µa at 267deg;C to 1 µa at 7.5°C. Threshold potential values ranged from 50 mv at 26°C to 6 mv at 7.5°C. The mean Q10 of threshold current was 2.3 (SD = 0.2), while the Q10 for threshold potentials was 2.0 (SD = 0.1).

scholarly journals Non-Linear Current-Potential Relations in an Axon Membrane

1961 ◽  
Vol 44 (6) ◽  
pp. 1055-1057 ◽  
Author(s):  
Kenneth S. Cole
Keyword(s):  
Membrane Potential ◽  
Giant Axon ◽  
Squid Giant Axon ◽  
External Current ◽  
Current Electrode ◽  
Axon Membrane ◽  
Linear Current ◽  
One Step ◽  
Original Derivation ◽  
Current Potential

The membrane current density, Im, in the squid giant axon has been calculated from the measured external current applied to the axon, Io, by the equation See PDF for Equation where Vm is the membrane potential under the current electrode and r1 and r2 are the external and internal longitudinal resistances. The original derivation of this equation included in one step an assumption of a linear relation between Im and Vm. It is shown that the same equation can be obtained without this restricting assumption.

scholarly journals RECTIFICATION AND INDUCTANCE IN THE SQUID GIANT AXON

1941 ◽  
Vol 25 (1) ◽  
pp. 29-51 ◽  
Author(s):  
Kenneth S. Cole
Keyword(s):  
Membrane Potential ◽  
Electrical Properties ◽  
Giant Axon ◽  
Squid Giant Axon ◽  
Constant Current ◽  
Ion Permeability ◽  
Squid Axon ◽  
Axon Membrane ◽  
Piezoelectric Structure ◽  
In Series

Previous measurements have shown that the electrical properties of the squid axon membrane are approximately equivalent to those of a circuit containing a capacity shunted by an inductance and a rectifier in series. Selective ion permeability of a membrane separating two electrolytes may be expected to give rise to the rectification. A quasi-crystalline piezoelectric structure of the membrane is a plausible explanation of the inductance. Some approximate calculations of behavior of an axon with these membrane characteristics have been made. Fair agreement is obtained with the observed constant current subthreshold potential and impedance during the foot of the action potential. In a simple case a formal analogy is found between the calculated membrane potential and the excitability defined by the two factor formulations of excitation. Several excitation phenomena may then be explained semi-quantitatively by further assuming the excitability proportional to the membrane potential. Some previous measurements and subthreshold potential and excitability observations are not consistent with the circuit considered and indicate that this circuit is only approximately equivalent to the membrane.

scholarly journals Thresholds and Plateaus in the Hodgkin-Huxley Nerve Equations

1960 ◽  
Vol 43 (5) ◽  
pp. 867-896 ◽  
Author(s):  
Richard Fitzhugh
Keyword(s):  
Membrane Conductance ◽  
Ionic Currents ◽  
Giant Axon ◽  
Analog Computer ◽  
Stable States ◽  
Axon Membrane ◽  
M Phase ◽  
Na Inactivation ◽  
Linear Differential ◽  
Phase Space Methods

Phase space methods and an analog computer are used to analyze the Hodgkin-Huxley non-linear differential equations for the squid giant axon membrane. V is the membrane potential, m the Na+ activation, h the Na+ inactivation, and n the K+ activation. V and m change rapidly, relative to h and n. The (V, m) phase plane of a reduced system of equations, with h and n held constant at their resting values, has three singular points: a stable resting point, a threshold saddle point, and a stable excited point. When h and n are allowed to vary, recovery and refractoriness result from the movement with subsequent disappearance of the threshold and excited points. Multiplying the time constant of n by 100 or more, and that of h by one-third, reproduces the experimental plateau action potentials obtained with tetraethylammonium by Tasaki and Hagiwara, including the phenomena of abolition and of refractoriness of the plateau duration. The equations have, transiently, two stable states, as found in the real axon by these authors. Since the theoretical membrane conductance curves differ significantly from the experimental ones, further experimental analysis of ionic currents with tetraethylammonium is needed to decide whether the Hodgkin-Huxley model can be generalized to explain these experiments completely.

scholarly journals Liquid Junction and Membrane Potentials of the Squid Giant Axon

1960 ◽  
Vol 43 (5) ◽  
pp. 971-980 ◽  
Author(s):  
Kenneth S. Cole ◽  
John W. Moore
Keyword(s):  
Membrane Potential ◽  
Sea Water ◽  
Specific Resistance ◽  
Cumulative Effect ◽  
Giant Axon ◽  
Squid Giant Axon ◽  
Liquid Junction ◽  
Axon Membrane ◽  
Best Value ◽  
Liquid Junction Potentials

The potential differences across the squid giant axon membrane, as measured with a series of microcapillary electrodes filled with concentrations of KCl from 0.03 to 3.0 M or sea water, are consistent with a constant membrane potential and the liquid junction potentials calculated by the Henderson equation. The best value for the mobility of an organic univalent ion, such as isethionate, leads to a probably low, but not impossible, axoplasm specific resistance of 1.2 times sea water and to a liquid junction correction of 4 mv. for microelectrodes filled with 3 M KCl. The errors caused by the assumptions of proportional mixing, unity activity coefficients, and a negligible internal fixed charge cannot be estimated but the results suggest that the cumulative effect of them may not be serious.

The kinetics of voltage-gated ion channels

1994 ◽  
Vol 27 (4) ◽  
pp. 339-434 ◽  
Author(s):  
R. D. Keynes
Keyword(s):  
Ion Channels ◽  
Ionic Currents ◽  
Giant Axon ◽  
General Information ◽  
Squid Giant Axon ◽  
Voltage Gated ◽  
Voltage Gated Ion Channels ◽  
Kinetics Of ◽  
Electrical Data ◽  
Gated Ion Channels

When Hodgkin & Huxley (1952) first embarked on the analysis of their voltageclamp data on the ionic currents in the squid giant axon, they hoped to be able to deduce a mechanism from it, but it soon became clear that the electrical data would by themselves yield only very general information about the class of system likely to be involved.

scholarly journals Mechanical characterization of squid giant axon membrane sheath and influence of the collagenous endoneurium on its properties

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Annaclaudia Montanino ◽  
Astrid Deryckere ◽  
Nele Famaey ◽  
Eve Seuntjens ◽  
Svein Kleiven
Keyword(s):  
Mechanical Characterization ◽  
Giant Axon ◽  
Squid Giant Axon ◽  
Axon Membrane
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