Previous spin-label and electromyographic experiments with rats fed 20,25-diazacholesterol, an inhibitor of the biosynthet ic conversion of desmostero[ to cholesterol, demonstrated an increased e ry th rocy te membrane f luidi ty and myotonia, a prolonged muscle contraction upon stimulation. The current studies with rats showed normal erythrocyte f luidi ty in animals fed 20,25-diazacholesterol...

A sporadic Japanese case of myotonia congenita with painful muscle cramps is reported. Electromyographic examinations disclosed myotonic discharge with dive bomber sounds at insertion, and high-amplitude, high-frequency motor unit potentials during the muscle cramps. Biopsied muscle specimens and EMGfindings showednon-specific mild myopathic changes. There was no abnormal expansion of CTGrepeat...

Mutations in the cytoplasmic tail (CT) of voltage gated sodium channels cause a spectrum of inherited diseases of cellular excitability, yet to date only one mutation in the CT of the human skeletal muscle voltage gated sodium channel (hNaV1.4F1705I) has been linked to cold aggravated myotonia. The functional effects of altered regulation of hNaV1.4F1705I are incompletely understood. The locati...