Repetitive CMAPs: Mechanisms of neural and synaptic genesis

Dijk, J. Gert van; Lammers, Gert Jan; Wintzen, Axel R.; Molenaar, Peter

doi:10.1002/(sici)1097-4598(199609)19:9<1127::aid-mus7>3.0.co;2-1

Cited by 43 publications

(13 citation statements)

References 41 publications

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“…Neuromuscular hyperactivity can be identified by EDs following the CMAP on motor nerve stimulation in cases of excess ACh at the neuromuscular junction (NMJ), including high dose of AChEIs, including organophosphate poisoning, congenital myasthenia with AChE deficiency and in slow-channel syndrome [22,23]. Since overt reactions to AChEIs with frequent nicotinergic symptoms such as muscle cramps, fasciculations and more pronounced fatigue have been reported to a relatively high extent in MuSK + MG [7], the administration of neostigmine served the purpose of a detailed in-vivo neurophysiological analysis of this medication at different doses and in MuSK + EAMG mice with low disease severity.…”

Section: Discussionsupporting

confidence: 83%

Neurophysiological characteristics of MuSK antibody positive Myasthenia Gravis mice: Focal denervation and hypersensitivity to acetylcholinesterase inhibitors

Chroni

Punga

2012

Journal of the Neurological Sciences

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Section: Discussionsupporting

confidence: 83%

Neurophysiological characteristics of MuSK antibody positive Myasthenia Gravis mice: Focal denervation and hypersensitivity to acetylcholinesterase inhibitors

Chroni

Punga

2012

Journal of the Neurological Sciences

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“…Our study has demonstrated that a similar refractory period may occur between the first two impulses of a NMT train, where the maximum recorded intraburst frequency is about 200–250 H Z . Other studies have reported similar findings of repetitive NMT discharges with a maximum intraburst frequency of 250–333 H Z also displaying refractoriness, where a second train of impulses could only be triggered by a second externally applied nerve stimulus after a period of 250 ms 25…”

Section: Discussionsupporting

confidence: 65%

Clinical electrophysiological characterization of the acquired neuromyotonia phenotype of autoimmune peripheral nerve hyperexcitability

2006

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Acquired autoimmune neuromyotonia is regarded as part of the spectrum of peripheral nerve hyperexcitability disorders. We aimed to use clinical neurophysiological measurements to study the extent, distribution, and characteristics of spontaneous motor unit potentials in 11 patients with acquired neuromyotonia. Investigations revealed that most spontaneous discharges recorded were motor unit, or partial motor unit potentials of normal size. Bursts of motor unit potentials arose more commonly from distal portions of the peripheral nerve and had abnormal absolute and relative refractory periods. Spontaneous discharges in some patients occurred in semirhythmic bursts in certain muscles. No patient had neurophysiological abnormalities detectable in first-order neurons of the central nervous system when using transcranial magnetic stimulation to estimate the threshold for corticomotor excitation and determine central motor conduction time. Only patients with coexistent myasthenia gravis had neurophysiologically detectable defects in neuromuscular transmission. The pathogenic region of abnormality in peripheral nerve hyperexcitability disorders therefore seems to lie within the terminal branches of peripheral motor nerves.

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“…Repetitive muscle discharge in response to a single nerve stimulus usually implies re‐excitation of muscle fibers by prolonged EPPs 3, 6, 7, 9. This is seen not only in congenital end‐plate AChE deficiency but also in other entities, such as organophosphate poisoning,1, 9 exposure to other anti‐acetylcholinesterases,3, 14 another form of congenital myasthenia called slow‐channel syndrome,6 and acquired slow‐channel syndrome 16. All of these conditions are characterized by prolonged end‐plate depolarization, which results from excess ACh caused by depression of AChE or abnormal channel kinetics of receptors.…”

Section: Discussionmentioning

confidence: 99%

Pathophysiology of weakness in a patient with congenital end‐plate acetylcholinesterase deficiency

et al. 2002

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A Japanese patient with congenital end-plate acetylcholinesterase (AChE) deficiency developed severe proximal and truncal muscle weakness with preservation of distal strength. Electrophysiological studies included a train of stimuli at 3 HZ, which induced a marked decremental response in the deltoid but not in the first dorsal interosseous (FDI) muscle. Single fiber electromyography (EMG) revealed a high blocking rate (23.1 +/- 30.5%, n = 13) with a markedly increased jitter (mean consecutive difference [MCD] 297 +/- 218 micros) in the deltoid, but a low blocking rate (6.2 +/- 7.4%, n = 16) despite an equally increased jitter (MCD 227 +/- 147 micros) in the FDI. In vitro microelectrode study and computer simulation suggested that the combination of a large jitter and a low blocking rate may be ascribed to a reduced end-plate potential (EPP) amplitude with an abnormally prolonged decay time constant (tau). These characteristics may constitute the primary underlying pathophysiologic mechanism in our patient and in similar cases of congenital myasthenic syndrome.

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Repetitive CMAPs: Mechanisms of neural and synaptic genesis

Cited by 43 publications

References 41 publications

Neurophysiological characteristics of MuSK antibody positive Myasthenia Gravis mice: Focal denervation and hypersensitivity to acetylcholinesterase inhibitors

Neurophysiological characteristics of MuSK antibody positive Myasthenia Gravis mice: Focal denervation and hypersensitivity to acetylcholinesterase inhibitors

Clinical electrophysiological characterization of the acquired neuromyotonia phenotype of autoimmune peripheral nerve hyperexcitability

Pathophysiology of weakness in a patient with congenital end‐plate acetylcholinesterase deficiency

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