Hi Paula, Sending you good vibes for a speedy recovery. I PMed you earlier with some personal recommendations for your extended rehab period.
As for potassium and acetylcholine, I have not researched that specific topic, though I know low potassium can cause leg cramps and severe muscle weakness, in addition to many other severe effects. It is a crucial component generating the electrical gradient across all membranes. On the other hand, too much potassium results in cessation of heart function.
I am reminded of Rick's post concerning potassium:

http://neurotalk.psychcentral.com/sh...t123+potassium

From wikipedia: http://en.wikipedia.org/wiki/Potassium

Potassium cations are important in neuron (brain and nerve) function, and in influencing osmotic balance between cells and the interstitial fluid, with their distribution mediated in all animals (but not in all plants) by the so-called Na+/K+-ATPase pump.[50] This ion pump uses ATP to pump three sodium ions out of the cell and two potassium ions into the cell, thus creating an electrochemical gradient over the cell membrane. In addition, the highly selective potassium ion channels (which are tetramers) are crucial for the hyperpolarization, in for example neurons, after an action potential is fired. ]
Membrane polarization
Potassium is also important in preventing muscle contraction and the sending of all nerve impulses in animals through action potentials.

Do you know if you possess the gene mutations noted in the reference?
madelyn