Dilantin - neuromyotonia and myelinopathy

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Hi ,

The abstract below is 5 years old, but read the last 7 lines. For a

short definition of Neuromyotonia read here

http://en.wikipedia.org/wiki/Neuromyotonia and here's a defintion of

myelinopathy - A disorder affecting the myelin of peripheral nerve

fibres, in contrast to one affecting axons (axonopathy). ~ G

Muscle Nerve. 2000 May;23(5):696-701.

Neuromyotonia in mice with hereditary myelinopathies.

Zielasek J, i R, Suter U, Toyka KV.

Department of Neurology, Julius-Maximilians-University, f-

Schneider-Str. 11, D-97080 Wurzburg, Germany.

The purpose of this study was to further characterize neuromyotonia

in mice with deletions and point mutations of myelin protein genes.

Clinical observation showed irregular stretching of the hindlimbs,

tremor and generalized myokymia in mice with targeted deletions of

the genes encoding myelin protein zero (P0-/-) or peripheral myelin

protein 22 (Pmp22-/-), and Trembler mice, which carry a point

mutation of Pmp22. By electromyography (EMG), we found irregular high-

frequency bursts of spontaneous motor unit activity and rhythmic

doublet or multiplet discharges of motor units in these mouse models

of human hereditary neuropathies. The EMG signs are typical for

neuromyotonia and myokymia, respectively. The activity persisted

after a proximal nerve section in many cases, localizing the

generator to the peripheral nerve or the muscle. We now show that

blocking neuromuscular transmission with suxamethonium abolished the

spontaneous activity, ruling out a muscle origin. Phenytoin

ameliorated the motor behavior. Taken together, our study shows that

neuromyotonia develops in different mouse models of hereditary

myelinopathies. This indicates that spontaneous motor unit activity

may underlie neuromyotonia, which is occasionally observed in Charcot-

Marie-Tooth disease. These animal models will be useful to study the

pathogenesis of neuromyotonia.