Potassium channels in nodal and internodal axonal membrane of mammalian myelinated fibres

Nature ◽  
1980 ◽  
Vol 284 (5752) ◽  
pp. 170-171 ◽  
Author(s):  
S. Y. Chiu ◽  
J. M. Ritchie
Keyword(s):  
Potassium Channels ◽  
Axonal Membrane ◽  
Myelinated Fibres

Differential distribution of potassium channels in acutely demyelinated, primary-auditory neurons in vitro

1996 ◽  
Vol 76 (1) ◽  
pp. 438-447 ◽  
Author(s):  
R. L. Davis
Keyword(s):  
Potassium Channels ◽  
Potassium Channel ◽  
Myelin Sheath ◽  
Lucifer Yellow ◽  
The Other ◽  
K Channel ◽  
Channel Activity ◽  
Auditory Neurons ◽  
Axonal Membrane ◽  
Voltage Dependent

1. Single-channel recordings of potassium channel activity were made from two populations of primary-auditory neurons maintained in tissue culture. The saccular nerve, which is the auditory component of the eighth cranial nerve in goldfish, was separated into two branches according to its peripheral innervation pattern. Neurons which innervated the rostral saccular macula corresponded to a class of cells that showed spike frequency adaptation; whereas, neurons which innervated the caudal macula were consistent with another type of cell that demonstrated bursting spontaneous firing patterns in vivo. Both somatic and internodal axonal membranes from each of these neuronal classes were studied after acute removal of the myelin sheath by microdissection. 2. Dye injections were used to discriminate neuronal from myelin membrane. After successful removal of the myelin, patch electrodes containing Lucifer yellow were used to fill a neuron and reveal its morphology within the myelin sheath. Patches on myelin led to filling of Schwann cells that surrounded the neuron. 3. Four kinds of potassium channels were observed and characterized according to unitary conductance, inactivation, and sensitivity to internal calcium. Three voltage-dependent K+ channel types were found on the somatic and axonal membrane of the two neuronal populations. Two channel types showed voltage-dependent inactivation and had average conductances of 32 and 19 pS, each with distinctive subconductance states. The third type of channel activity had an estimated conductance of 12 pS and was noninactivating. 4. The fourth type of channel was the Ca2(+)-activated K+ channel (k(Ca)), which was classified by the dependence of its activity on the calcium concentration at its cytoplasmic surface. Unlike the other three potassium channel types, this kind of channel was found exclusively on neurons that innervated the caudal sensory epithelium. As with the other kinds of potassium channels, it was found on both somatic and axonal internodal membranes.

scholarly journals The Myelin Sheath Maintains the Spatiotemporal Fidelity of Action Potentials by Eliminating the Effect of Quantum Tunneling of Potassium Ions through the Closed Channels of the Neuronal Membrane

2019 ◽  
Vol 1 (2) ◽  
pp. 287-294 ◽  
Author(s):  
Abdallah Barjas Qaswal
Keyword(s):  
Potassium Channels ◽  
Action Potential ◽  
Myelin Sheath ◽  
Quantum Tunneling ◽  
Action Potentials ◽  
Quantum Physics ◽  
Demyelinating Diseases ◽  
Neuronal Membrane ◽  
Potassium Ions ◽  
Axonal Membrane

The myelin sheath facilitates action potential conduction along the axons, however, the mechanism by which myelin maintains the spatiotemporal fidelity and limits the hyperexcitability among myelinated neurons requires further investigation. Therefore, in this study, the model of quantum tunneling of potassium ions through the closed channels is used to explore this function of myelin. According to the present calculations, when an unmyelinated neuron fires, there is a probability of 9.15 × 10 − 4 that it will induce an action potential in other unmyelinated neurons, and this probability varies according to the type of channels involved, the channels density in the axonal membrane, and the surface area available for tunneling. The myelin sheath forms a thick barrier that covers the potassium channels and prevents ions from tunneling through them to induce action potential. Hence, it confines the action potentials spatiotemporally and limits the hyperexcitability. On the other hand, lack of myelin, as in unmyelinated neurons or demyelinating diseases, exposes potassium channels to tunneling by potassium ions and induces the action potential. This approach gives different perspectives to look at the interaction between neurons and explains how quantum physics might play a role in the actions occurring in the nervous system.

Potassium channels in the nodal membrane of rat myelinated fibres

Nature ◽  
1981 ◽  
Vol 290 (5807) ◽  
pp. 598-600 ◽  
Author(s):  
Ofer Binah ◽  
Yoram Palti
Keyword(s):  
Potassium Channels ◽  
Nodal Membrane ◽  
Myelinated Fibres

Dopamine and GABA outflow is modulated by ATP-sensitive potassium channels in the rat caudate nucleus

2006 ◽  
Vol 33 (S 1) ◽  
Author(s):  
H. Fuellgraf ◽  
M. Steinkamp ◽  
M. Kolbe ◽  
A. Moser
Keyword(s):  
Potassium Channels ◽  
Caudate Nucleus

Design of New Openers of ATP-Sensitive Potassium Channels of the Cell Membranes

2016 ◽  
Vol 12 (4) ◽  
pp. 36-44
Author(s):  
R.B. Strutynskyi ◽  
◽  
N.A. Strutynska ◽  
O.P. Maximyuk ◽  
M.O. Platonov ◽  
...  
Keyword(s):  
Potassium Channels ◽  
Cell Membranes
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