Experimental Drug May Restore Function of Nerves
Posted: Fri Nov 20, 2009 12:20 pm
This is your friend again...
What a pity that potassium channel blockers prevent any possible remyelination...
The role of myelin is not just potassium channel covering. It reduces the impedance of the axon by presenting a layer of capacitors around it (the multiple sheaths behave as the foils of a capacitor) and increases the insulation.
When an axon fires, potassium leaves the body and sodium comes in, making it more positive, electrically. Myelin makes this signal travel along the axon requiring fewer "retransmissions" (exchange between sodium and potassium again), thus less time. Then, sodium exits the body and potassium reenters it.
Blocking the potassium channels could make the signal travel a bit further, however it could very well lead into seizures. In addition, blocking the potassium channels throughout the body (not only inside the CNS) could cause problems to the heart and muscles.
Aminopyridine could prove a very useful drug, despite some disappointing results, so far. But remyelination prevention worries me much...
sou