PMID- 21747141
OWN - NLM
STAT- MEDLINE
DCOM- 20110825
LR  - 20110712
IS  - 1881-6096 (Print)
IS  - 1881-6096 (Linking)
VI  - 63
IP  - 7
DP  - 2011 Jul
TI  - [Neurophysiologic assessment of disorders affecting the neuromuscular junction].
PG  - 713-7
AB  - The neuromuscular junction (NMJ) is a specialized synapse with a complex 
      structural organization. Muscle contraction involves several steps: (1) nerve 
      conduction to depolarize the motor nerve terminals, (2) opening of voltage-gated 
      calcium channels (VGCCs) in the presynaptic membrane, (3) generation of endplate 
      potential in the postsynaptic membrane via acetylcholine receptors, (4) 
      depolarization of muscle sodium channels, and (5) excitation-contraction (E-C) 
      coupling. Each step can be affected by various diseases. Guillain-Barre syndrome 
      involves distal axons and possibly the presynaptic NMJ. The abnormalities can be 
      detected by nerve conduction studies and single-fiber electromyography (SFEMG). 
      Myasthenia gravis (MG) with anti-acetylcholine receptor (AChR) antibodies, is the 
      most common NMJ disorder, and ~5% of myasthenia patients are positive for 
      anti-muscle specific kinase (MuSK) antibodies. Patterns and severity of 
      neuromuscular transmission failure detected by repetitive nerve stimulation test 
      and SFEMG are somewhat different in AChR-MG and MuSK-MG. Excitation-contraction 
      (E-C) coupling can be affected by MG, possibly via antibodies against ryanodine 
      receptors. The E-C coupling time can be assessed with an accelerometer. 
      Lambert-Eaton myasthenic syndrome is caused by antibodies against presynaptic 
      VGCCs. This review will focus on neurophysiological testing, including SFEMG, and 
      measurements of E-C coupling time with an accelerometer. In addition to 
      confirming or excluding the diagnosis, these techniques can provide new insights 
      into the pathophysiology of a variety of neuromuscular disorders.
FAU - Kuwabara, Satoshi
AU  - Kuwabara S
AD  - Department of Neurology, Graduate School of Medicine, Chiba University, Chiba, 
      Japan.
LA  - jpn
PT  - English Abstract
PT  - Journal Article
PT  - Review
PL  - Japan
TA  - Brain Nerve
JT  - Brain and nerve = Shinkei kenkyu no shinpo
JID - 101299709
SB  - IM
MH  - Electromyography
MH  - Humans
MH  - Myasthenia Gravis/physiopathology
MH  - Neuromuscular Junction Diseases/diagnosis/*physiopathology
EDAT- 2011/07/13 06:00
MHDA- 2011/08/27 06:00
CRDT- 2011/07/13 06:00
PHST- 2011/07/13 06:00 [entrez]
PHST- 2011/07/13 06:00 [pubmed]
PHST- 2011/08/27 06:00 [medline]
AID - 1416100952 [pii]
PST - ppublish
SO  - Brain Nerve. 2011 Jul;63(7):713-7.