Thursday, 18 February 2016

Education:How a nerve transmits recap

Yesterday we examined how nerves transmit and we have voltage gated sodium and potassium channels working in concert. Here's a recap


So as the action potential (nerve impulse) arrives it causes membrane depolarisation because the sodium channels open. Sodium enters the nerve

Then repolarisation as the sodium channels close and potassium channels open. This resets the nerve.


5 comments:

  1. Still waiting to hear if sodium channel drugs are safe to use with potassium drugs (Ampyra).

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    Replies
    1. I was once prescribed Tegretol, (a sodium channel blocker), even though I was on Fampridine, (potassium channel blocker).

      After 4 days the two drugs cancelled each other out and I couldn't walk. I ceased the Tegretol and regained walking ability after 2 days. So no damage, but they just counteract each other.

      I would love to be on sodium channel blockers because of their neuro-protective possibilities. But the positive benefits of walking mean I will keep off them until some other walking drugs are discovered that can be taken with sodium channel blockers.

      Incidentally, a 2009 paper in the Journal of Biology suggested that 4-AP and it's analogues do block potassium channels, but their ability to help nerve impulses travel along the axons might be due to its effect on the Calcium channels as well. A pure potassium channel blocker does not help nerve impulses travel (tested in rats, not humans).

      So are there any other drugs out there that might be used to help walking that can be used with sodium channel blockers so that we get the best of both worlds?

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    2. I suspect the trick is to have a potassium channel oepner.

      Have Biogen made a nice video explaining how ampyra works? We wondered whether amprya did the opposite to sodium chanel blockers, but Biogen weren't interested at the time.

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    3. I took Tegretol 30 years ago on its own. I had a horrible reaction to it. It made me very wary of the drugs I'm offered.

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  2. Ampyra is made by Acorda. Don't know.

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