Google sodium depletion effects on the nervous system.
Ditto the effects of potassium depletion and excess on myocardial tissue.
In short, "sustained" changes in the cell PD acroos the cell wall would make you somewhat dead before any possible "side issues" would take hold.
Cells have had millions of years of evolution to do what they do, and NEED to work within a very tight, homeostatically balanced, biological environment.
Yes, renal patients can kill themselves with a fruit salad (bananas and strawberries -high in K) as they cannot remove the excess from their circulation.
Everyone can "drown" themselves by drinking way too much water (ca 20% of your bodyweight in a day) leading to the Na depletion of the CNS.
