scholarly journals Tuning of Ranvier node and internode properties in myelinated axons to adjust action potential timing

2015 ◽  
Vol 6 (1) ◽  
Author(s):  
Marc C. Ford ◽  
Olga Alexandrova ◽  
Lee Cossell ◽  
Annette Stange-Marten ◽  
James Sinclair ◽  
...  
Keyword(s):  
Action Potential ◽  
Ranvier Node ◽  
Myelinated Axons

Emergence of an optimal temperature in action-potential propagation through myelinated axons

2019 ◽  
Vol 100 (3) ◽  
Author(s):  
Xinlin Song ◽  
Hengtong Wang ◽  
Yong Chen ◽  
Ying-Cheng Lai
Keyword(s):  
Action Potential ◽  
Optimal Temperature ◽  
Myelinated Axons ◽  
Action Potential Propagation

Dendrotoxin blocks accommodation in frog myelinated axons

1989 ◽  
Vol 62 (1) ◽  
pp. 174-184 ◽  
Author(s):  
M. O. Poulter ◽  
T. Hashiguchi ◽  
A. L. Padjen
Keyword(s):  
Action Potential ◽  
Computer Model ◽  
Action Potentials ◽  
Potassium Conductance ◽  
Constant Stimulus ◽  
Motor Axons ◽  
Myelinated Axons ◽  
Frequency Adaptation ◽  
Potassium Conductances ◽  
Slow Potassium

1. Intracellular microelectrode recordings from large sensory and motor myelinated axons in spinal roots of Rana pipiens were used to study the effects of dendrotoxin (DTX), a specific blocker of a fast activating potassium current (GKf1). 2. Dendrotoxin reduced the ability of myelinated sensory and motor axons to accommodate to a constant stimulus. A depolarizing current step, which normally evoked only one action potential, after dendrotoxin treatment (200-500 nM) produced a train of action potentials. These spike trains lasted 29 +/- 2.8 (SE) ms on average in sensory fibers (n = 18) and 40.2 +/- 4.5 ms in motor fibers (n = 9). 3. After dendrotoxin treatment, in addition to a reduction in the ability to accommodate to a constant stimulus, a slowing in the rate of action potential generation was evident (spike frequency adaptation). 4. Dendrotoxin had no effect on the rising phase of conducted action potentials evoked by peripheral stimulation. Together with a lack of effect on the absolute refractory period, these results indicate that dendrotoxin does not affect sodium channel activity. 5. The steady-state voltage/current relationship was unchanged in response to hyperpolarizing current pulses; however, there was a significant increase in cord resistance in response to depolarizing current steps, demonstrating that DTX decreases outward rectification. 6. A computer model based on Hodgkin and Huxley equations was developed, which included the three voltage-dependent potassium conductances described by Dubois. The model reproduced major experimental results: removal of the conductance, termed GKf1, reduced the accommodation in the early phase of a continuous stimulus, indicating that this current could be responsible for the early accommodation. The hypothesis that the slow potassium conductance GKs regulates late accommodation and action potential frequency adaptation is also supported by the computer model. 7. In summary, these results suggest that in amphibian myelinated sensory and motor axons, the activity of potassium conductances can account for accommodation and adaptation without involvement of sodium conductance activity.

Is the rise of the action potential of the ranvier node controlled by a paranodal organ?

1974 ◽  
Vol 61 (8) ◽  
pp. 369-370 ◽  
Author(s):  
H. M�ller-Mohnssen ◽  
A. Tippe ◽  
F. Hillenkamp ◽  
E. Uns�ld
Keyword(s):  
Action Potential ◽  
Ranvier Node

scholarly journals EFFECTS OF CALCIUM LACK ON ACTION POTENTIAL OF MOTOR AXONS OF THE LOBSTER LIMB

1959 ◽  
Vol 42 (3) ◽  
pp. 655-664 ◽  
Author(s):  
W. J. Adelman ◽  
J. Adams
Keyword(s):  
Action Potential ◽  
Refractory Period ◽  
Free Solution ◽  
Myelinated Axons ◽  
Similar Time ◽  
The Mean ◽  
Time Courses ◽  
High Degree ◽  
External Calcium ◽  
Linear Decline

The effects of external calcium deprivation on certain characteristics of the action potential of the lobster motor axon have been studied. Upon exposure to calcium-free solution the spike amplitude is rapidly decreased within a few minutes and is followed by a slow linear decline. The rates of spike rise and fall are proportionally reduced more than the spike but follow similar time courses during calcium lack. Associated with these phenomena are the loss in the normal slow spike repolarization process, the development of a large and lengthy undershoot, and the appearance of a high degree of refractoriness. The mean increase in the refractory period is 525 per cent upon 10 minutes' exposure to calcium-free solution. These effects are completely reversible upon returning the axons to normal solution. These results are compared to similar effects of calcium deprivation on frog myelinated axons and squid and lobster giant axons recently observed by other workers.

scholarly journals Physical model of electrical synapses in a neural network

2021 ◽  
Author(s):  
Mikhail Pekker ◽  
Mikhail Shneider
Keyword(s):  
Neural Network ◽  
Theoretical Model ◽  
Action Potential ◽  
Physical Model ◽  
Nodes Of Ranvier ◽  
Myelinated Axons ◽  
Active Neuron ◽  
Electrical Synapses ◽  
Ephaptic Coupling

A theoretical model of electrical synapses is proposed, in which connexons play the role of nails that hold unmyelinated areas of neurons at a distance of about 3.5 nm, and the electrical connection between them is provided by charging the membrane of an inactive neuron with currents generated in the intercellular electrolyte (saline) by the action potential in the active neuron. This mechanism is similar to the salutatory conduction of the action potential between the nodes of Ranvier in myelinated axons and the ephaptic coupling of sufficiently close spaced neurons.

Enhanced Action Potential Passage Through the Node of Ranvier of Myelinated Axons via Proton Hopping

2015 ◽  
Vol 11 (1) ◽  
pp. 5-7 ◽  
Author(s):  
Lemont Kier ◽  
Lowell Hall ◽  
Robert Tombes
Keyword(s):  
Action Potential ◽  
Node Of Ranvier ◽  
Myelinated Axons
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