Demonstration of Sodium and Potassium Conductance Changes during a Nerve Action Potential

Nature ◽  
1970 ◽  
Vol 225 (5234) ◽  
pp. 747-748 ◽  
Author(s):  
E. ROJAS ◽  
F. BEZANILLA ◽  
R. E. TAYLOR
Keyword(s):  
Action Potential ◽  
Potassium Conductance ◽  
Nerve Action ◽  
Conductance Changes ◽  
Sodium And Potassium

scholarly journals Sodium and potassium conductance changes during a membrane action potential

1970 ◽  
Vol 211 (3) ◽  
pp. 729-751 ◽  
Author(s):  
Francisco Bezanilla ◽  
Eduardo Rojas ◽  
Robert E. Taylor
Keyword(s):  
Action Potential ◽  
Potassium Conductance ◽  
Membrane Action ◽  
Conductance Changes ◽  
Sodium And Potassium

scholarly journals The exponential tracking and disturbance rejection of the propagated membrane action potential with conductance coefficient feedforward controllers

2021 ◽  
Author(s):  
Weijiu Liu
Keyword(s):  
Action Potential ◽  
Disturbance Rejection ◽  
Surface Membrane ◽  
Potassium Conductance ◽  
Initial Condition ◽  
Membrane Action ◽  
Feedback Controllers ◽  
Pde Model ◽  
Potassium Conductances ◽  
Sodium And Potassium

In the early 1950's, using their experimental data, Hodgkin and Huxley constructed the sodium and potassium conductance feedback controllers for their mathematical model of the flow of electric current through the surface membrane of a giant nerve fibre. In this paper, we re-formulate the construction as a problem of exponential tracking and disturbance rejection and then re-construct new conductance feedforward controllers in the more complicated case of a propagated action potential. The dynamics of the potential is governed by the Hodgkin-Huxley's partial differential equation (PDE) model. The problem is solved for any current disturbances and potential references and conductance coefficient feedforward controllers are designed by using the method of variable transform. It is proved that, under the designed feedforward controllers, the potential tracks exponentially a desired potential reference uniformly on an interval of one unit and the reference satisfies the controlled PDE model except an initial condition. A numerical example shows that the simulated action potential and sodium and potassium conductances are close to the experimental observations.

scholarly journals Competitive Action of Calcium and Procaine on Lobster Axon

1966 ◽  
Vol 49 (5) ◽  
pp. 1043-1063 ◽  
Author(s):  
Mordecai P. Blaustein ◽  
David E. Goldman
Keyword(s):  
Calcium Concentration ◽  
Potassium Conductance ◽  
Membrane Conductance ◽  
Giant Axon ◽  
Sodium Conductance ◽  
Potassium Conductances ◽  
Conductance Changes ◽  
Sodium And Potassium ◽  
External Calcium

Voltage clamp studies with the squid giant axon have shown that changes in the external calcium concentration (Frankenhaeuser and Hodgkin, 1957) shift the sodium and potassium conductance versus membrane potential curves along the potential axis. Taylor (1959) found that procaine acts primarily by reducing the sodium and, to a lesser extent, the potassium conductances. Both procaine and increased calcium also delay the turning on of the sodium conductance mechanism. Calcium and procaine have similar effects on lobster giant axon. In addition, we have observed that the magnitude of the response to procaine is influenced by the external calcium concentration. Increasing external calcium tends to reduce the effectiveness of procaine in decreasing sodium conductance. Conversely, procaine is more effective in reducing the membrane conductance if external calcium is decreased. The amplitude of the nerve action potential reflects these conductance changes in that, for example, reductions in amplitude resulting from the addition of procaine to the medium are partially restored by increasing external calcium, as was first noted by Aceves and Machne (1963). These phenomena suggest that calcium and procaine compete with one another with respect to their actions on the membrane conductance mechanism. The fact that procaine and its analogues compete with calcium for binding to phospholipids in vitro (Feinstein, 1964) suggests that the concept of competitive binding to phospholipids may provide a useful model for interpreting these data.

scholarly journals The exponential tracking and disturbance rejection of the propagated membrane action potential with conductance coefficient feedforward controllers

2021 ◽  
Author(s):  
Weijiu Liu
Keyword(s):  
Action Potential ◽  
Disturbance Rejection ◽  
Surface Membrane ◽  
Potassium Conductance ◽  
Initial Condition ◽  
Membrane Action ◽  
Feedback Controllers ◽  
Pde Model ◽  
Potassium Conductances ◽  
Sodium And Potassium

In the early 1950's, using their experimental data, Hodgkin and Huxley constructed the sodium and potassium conductance feedback controllers for their mathematical model of the flow of electric current through the surface membrane of a giant nerve fibre. In this paper, we re-formulate the construction as a problem of exponential tracking and disturbance rejection and then re-construct new conductance feedforward controllers in the more complicated case of a propagated action potential. The dynamics of the potential is governed by the Hodgkin-Huxley's partial differential equation (PDE) model. The problem is solved for any current disturbances and potential references and conductance coefficient feedforward controllers are designed by using the method of variable transform. It is proved that, under the designed feedforward controllers, the potential tracks exponentially a desired potential reference uniformly on an interval of one unit and the reference satisfies the controlled PDE model except an initial condition. A numerical example shows that the simulated action potential and sodium and potassium conductances are close to the experimental observations.

How Gymnodinium breve red tide toxin(s) produces repetitive firing in squid axons

1977 ◽  
Vol 232 (1) ◽  
pp. 23-29 ◽  
Author(s):  
M. Westerfield ◽  
J. W. Moore ◽  
Y. S. Kim ◽  
G. M. Padilla
Keyword(s):  
Action Potential ◽  
Action Potentials ◽  
Red Tide ◽  
Potassium Conductance ◽  
Giant Axon ◽  
Resting Potential ◽  
Repetitive Firing ◽  
Gymnodinium Breve ◽  
Rate Of Recovery ◽  
Conductance Changes

Partially purified toxin(s), GbTX, extracted from Gymnodinium breve red tide organisms elicits a spontaneous train of action potentials in the squid giant axon. The spikes have a shape similar to that in the normal seawater control except for an increase in the rate of recovery from the afterhyperpolarization. With this more rapid recovery, the membrane potential overshoots the resting potential and threshold, triggers another spike, and thus produces repetitive firing. Voltage-clamp studies revealed that the toxin has no effect on the normal sodium or potassium conductance changes produced by step depolarization. However, consistent with the faster recovery after an action potential, GbTX speeds recovery of the “shut-off” currents to their steady-state values after a depolarization. The most likely mechanism by which the toxin accelerates recovery after an action potential (leading to repetitive firing) is the induction of a small additional inward current which was found to be reduced by prehyperpolarization. This toxin-induced current which speeds recovery is blocked by tetrodotoxin and hence presumably flows through the sodium channel.

scholarly journals Electrophysiological diagnosis using sensory nerve action potential for the intraforaminal and extraforaminal L5 nerve root entrapment

2012 ◽  
Vol 22 (4) ◽  
pp. 833-839 ◽  
Author(s):  
Muneharu Ando ◽  
Tetsuya Tamaki ◽  
Mamoru Kawakami ◽  
Akihito Minamide ◽  
Yukihiro Nakagawa ◽  
...  
Keyword(s):  
Action Potential ◽  
Nerve Root ◽  
Sensory Nerve ◽  
Sensory Nerve Action Potential ◽  
Nerve Action ◽  
Sensory Nerve Action ◽  
Nerve Root Entrapment

A model of the nerve action potential

1979 ◽  
Vol 46 (1-2) ◽  
pp. 11-36 ◽  
Author(s):  
Jonathan Bell ◽  
L. Pamela Cook
Keyword(s):  
Action Potential ◽  
Nerve Action
Sign in / Sign up

Export Citation Format

Share Document