title: Endomicroscopy and electromyography of neuromuscular junctions in situ.
abstract: OBJECTIVE
  Electromyography (EMG) is used routinely to diagnose neuromuscular dysfunction in a wide range of peripheral neuropathies, myopathies, and neuromuscular degenerative diseases including motor neuron diseases such as amyotrophic lateral sclerosis (ALS). Definitive neurological diagnosis may also be indicated by the analysis of pathological neuromuscular innervation in motor-point biopsies. Our objective in this study was to preempt motor-point biopsy by combining live imaging with electrophysiological analysis of slow degeneration of neuromuscular junctions (NMJs) in vivo.
  
  
  METHODS
  We combined conventional needle electromyography with fiber-optic confocal endomicroscopy (CEM), using an integrated hand-held, 1.5-mm-diameter probe. We utilized as a test bed, various axotomized muscles in the hind limbs of anaesthetized, double-homozygous thy1.2YFP16: Wld (S) mice, which coexpress the Wallerian-degeneration Slow (Wld(S)) protein and yellow fluorescent protein (YFP) in motor neurons. We also tested exogenous vital stains, including Alexa488-α-bungarotoxin; the styryl pyridinium dye 4-Di-2-Asp; and a GFP conjugate of botulinum toxin Type A heavy chain (GFP-HcBoNT/A).
  
  
  RESULTS
  We show that an integrated EMG/CEM probe is effective in longitudinal evaluation of functional and morphological changes that take place over a 7-day period during axotomy-induced, slow neuromuscular synaptic degeneration. EMG amplitude declined in parallel with overt degeneration of motor nerve terminals. EMG/CEM was safe and effective when nerve terminals and motor endplates were selectively stained with vital dyes.
  
  
  CONCLUSIONS
  Our findings constitute proof-of-concept, based on live imaging in an animal model, that combining EMG/CEM may be useful as a minimally invasive precursor or alternative to motor-point biopsy in neurological diagnosis and for monitoring local administration of potential therapeutics.
authors.affiliation: Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh Hugh Robson Building, George Square, Edinburgh, EH8 9XD, United Kingdom.
authors.forename: Rosalind
authors.initials: R
authors.lastname: Brown
authors.affiliation: Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh Hugh Robson Building, George Square, Edinburgh, EH8 9XD, United Kingdom.
authors.forename: Kosala N
authors.initials: KN
authors.lastname: Dissanayake
authors.affiliation: Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh Hugh Robson Building, George Square, Edinburgh, EH8 9XD, United Kingdom.
authors.forename: Paul A
authors.initials: PA
authors.lastname: Skehel
authors.affiliation: Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh Hugh Robson Building, George Square, Edinburgh, EH8 9XD, United Kingdom.
authors.forename: Richard R
authors.initials: RR
authors.lastname: Ribchester