Introduction Dysport Certification Training (abobotulinumtoxin A) History of Botulinum Neurotoxin A In 1950, researchers at McGill discovered that botulinum toxin from the bacterial Clostridium botulinum presynaptically blocked the release of acetylcholine from motor nerve terminals. Effect was muscle weakening due to chemical denervation. It was also discovered that botulinum toxins blocked the exocytosis of acetylcholine…