The muscle membrane in myotonia congenita is characterized by a normal resting potential
with a greatly increased resting resistance usually attributed to a decrease in membrane
chloride permeability (P cl). In this report, the hypothesis that decreased P cl alone can
account for the repetitive action potentials of myotonia is tested with a mathematical model of
the muscle membrane and is shown to be valid. Reduction of P cl to 20% of control values
will produce myotonic activity in response to a single stimulus. Membrane resistance and …