Neuromuscular

TERMINAL MOTOR AXONS & NEUROMUSCULAR JUNCTIONS

Acrylamide
Age
Atrophy
Axon Regrowth
  Ultraterminal sprouts (Botulinum toxin)
  Collateral sprouts
  Regeneration
CIDP
MMN
Dimethyaminopropionitrile (DMAPN)
Normal

Normal


Human: Silver-P0-Esterase stain

Rat: Silver-P0-Esterase stain
Normal neuromuscular junctions

Collateral sprouting


Collateral sprouting in patient with ALS

Silver-P0-Esterase stain


Silver (Black)-Esterase (Blue) stain: Rat muscle
Collateral Sprouting (Rat)
  Collateral sprouts: Several sprouts innervate one NMJ
    From Intact axons to Denervated NMJ (Arrow)
    May originate from
      Terminal axon branches (Above), or
      Preterminal axon (Below)

Silver (Blue)-Esterase (Blue) stain: Rat muscle

Collateral sprouts (Arrow)
  Preterminal axon origin: Arise from Nodes of Ranvier
  Size: Thin compared to original axon

Silver (Black)-Esterase (Blue) stain: Rat muscle

Axon Regeneration: Single axon innervates several NMJs

Silver (Black)-Esterase (Blue) stain: Rat muscle

Axon Atrophy

Silver-P0-Esterase stain
Loss of myelin sheath toward end of an atrophic axon

Botulinum Toxin


Silver-Esterase stain
Botulinum treatment (Rat)
NMJ: Enlarged
  Elongated
  2 segments
  Motor axon terminal: Increased branching

Botulinum Toxin Treatment: Ultraterminal sprouts

Silver-Esterase stain
Terminal axons at Neuromuscular junctions (Rat)
Botulinum toxin induces
  Enlargement of NMJs (middle) &
  Ultraterminal sprouts (Arrows) extending from nerve terminals at NMJs (middle & top)
Control NMJ (Bottom)

Acrylamide


Silver-Esterase stain

Acrylamide intoxication (Rat)
  Motor nerve terminals: Focal Enlargements

Dimethyaminopropionitrile


Silver-Esterase stain

Dimethyaminopropionitrile (DMAPN) intoxication (Rat)
  Swelling in sprout & axon terminal branches in NMJ
  Ultraterminal sprout with swelling (Top left)

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2/18/2021