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Variability and failure of neurotransmission in the diaphragm of mdx mice.
- Source :
-
Neuromuscular disorders : NMD [Neuromuscul Disord] 2006 Mar; Vol. 16 (3), pp. 168-77. Date of Electronic Publication: 2006 Feb 17. - Publication Year :
- 2006
-
Abstract
- Loss of specific muscle force and evidence of myopathy are present in the diaphragm of mdx mice by 4 weeks of age. The neuromuscular junction of dystrophic muscle also shows structural abnormalities at this age. Whether these structural alterations result in neural transmission abnormalities is currently unclear, particularly at physiological firing frequencies. Thus, we investigated the extent of neurotransmission variability and failure during 35 and 100 Hz stimulation in the diaphragm of 6 to 8-month-old mdx mice in comparison to age-matched controls. Neurotransmission failure was similar across groups at both stimulation frequencies, despite the presence of disrupted post-synaptic acetylcholine receptors (AChRs). Neural transmission variability, however, measured by comparing variation in force production during direct muscle stimulation compared to variation in force production during phrenic nerve stimulation was significantly greater in dystrophic muscle. Together, these results suggest that neurotransmission is maintained at physiologic firing frequencies in dystrophic muscle, but the precision of neurotransmission is attenuated. A reduced density of functional AChRs likely underlies the increase in neurotransmission variability.
- Subjects :
- Animals
Bungarotoxins pharmacokinetics
Dose-Response Relationship, Radiation
Electric Stimulation methods
Immunohistochemistry methods
In Vitro Techniques
Mice
Mice, Inbred C57BL
Mice, Inbred mdx
Muscle Contraction physiology
Muscle Contraction radiation effects
Phrenic Nerve physiopathology
Phrenic Nerve radiation effects
Receptors, Cholinergic metabolism
Diaphragm physiopathology
Synaptic Transmission physiology
Subjects
Details
- Language :
- English
- ISSN :
- 0960-8966
- Volume :
- 16
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- Neuromuscular disorders : NMD
- Publication Type :
- Academic Journal
- Accession number :
- 16483776
- Full Text :
- https://doi.org/10.1016/j.nmd.2006.01.002