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Neuromuscular transmission in the mdx mouse
A Nagel1, F Lehmann-Horn, A G Engel
1Department of Neurology, Mayo Clinic, Rochester, MN 55905.
Muscle & Nerve
|August 1, 1990
Summary
Dystrophin deficiency in muscular dystrophy causes muscle membrane vulnerability and neuromuscular junction abnormalities. Electrophysiology revealed altered potentials but preserved neuromuscular transmission safety margins in mdx mice.
Area of Science:
- Neuromuscular Disorders
- Muscle Physiology
- Neuroscience
Background:
- Dystrophin deficiency compromises muscle fiber plasma membrane integrity.
- Ultrastructural abnormalities are observed at the postsynaptic membrane of the neuromuscular junction in muscular dystrophy.
Purpose of the Study:
- To investigate if ultrastructural changes at the mdx neuromuscular junction correlate with impaired neuromuscular transmission.
- To assess neuromuscular transmission in dystrophin-deficient mdx mice.
Main Methods:
- Electrophysiologic recordings were performed on mdx mice and age-matched controls.
- Analysis focused on miniature end-plate potential amplitude and quantal content of end-plate potentials.
Main Results:
- Mdx mice exhibited an age-dependent reduction in miniature end-plate potential amplitude.
- Quantal content of end-plate potentials increased concurrently in mdx mice compared to controls.
- Despite alterations, the safety margin of neuromuscular transmission remained unimpaired.
Conclusions:
- Ultrastructural abnormalities at the mdx neuromuscular junction are associated with specific electrophysiologic changes.
- Neuromuscular transmission is functionally preserved in mdx mice, indicating a maintained safety margin.