Neuromuscular transmission in myasthenic single motor units.
AUTOR(ES)
Kadrie, H A
RESUMO
In patients with myasthenia gravis neuromuscular transmission has been tested in individual hypothenar and thenar motor units using trains of near threshold electrical stimuli delivered to the motor nerve. The most important observations included: (1) the proportion of motor units with pathological decrements varied from 0 to 90%, (2) the decrements in surface voltage were frequently much more normal in individual motor units than in the corresponding maximum compound potentials evoked by supramaximal nerve stimulation, and (3) the most abnormal decrements were observed in motor units at the low end of the surface voltage range. These observations can be interpreted to suggest important neurogenic factors in the pathogenesis of myasthenia gravis. An attractive alternative would be to suggest that the small motor units have the most abnormal neuromuscular transmission because they normally have a lower margin for safe neuromuscular transmission and, as a consequence, fail first in diseases of neuromuscular transmission.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=492998Documentos Relacionados
- Neuromuscular transmission in human single motor units.
- Regulation of the firing pattern of single motor units.
- Motor units in a skeletal muscle of neonatal rat: mechanical properties and weak neuromuscular transmission.
- Axonal refractory period of single short toe extensor motor units in neuropathies and neuromuscular diseases.
- Relationship between electrical and mechanical properties of motor units.