Botulinum toxin

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Botulinum toxin

• Kristen
• Alison
• Claire

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• Botulinum Toxin is the most poisonous substance
  know to man
• It can be used as a deadly weapon in biological
  warfare
• One gram of crystalline toxin evenly dispersed
  and inhaled would kill more than one million
  people.
  
• Journal of American Medicine
  
  
  
• http//jama.ama-assn.org/cgi/content/full/285
  /8/1059

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What is Botulinum?

• Botulinum toxin is produced by the bacteria
  Clostridium botulinum, an anaerobic, spore
  forming strain commonly found in soil
• Botulism is a form of food poisoning from
  undercooked foods that are contaminated with the
  toxinmost often found in ill- prepared canned
  foods

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How botulinum poisoning occurs

• Botulinum irreversibly prevents ACh from being
  exocytosed into the synaptic cleft
• The death of this part of the neuron may take a
  month or longer, although synaptic transmission
  ceases almost immediately

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Effects on Pre and Post Synapse

• Parameter
• Pre-synaptic resting potential
• Pre-synaptic action potential amplitude
• Pre-synaptic Ca2 influx
• Pre-synaptic neurotransmitter release
• Post-synaptic resting potential
• Post-synaptic end plate potential
• Post-synaptic action potential amplitude
• Post-synaptic action potential frequency
• Whole muscle contraction strength

• Prediction
• no Change
• no Change
• no Change
• Decrease or Stops
• no Change
• decrease
• no change (or none generated)
• decrease
• decrease in whole muscle strength and eventual
  paralysis

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Medicinal Uses for Botox

• uncontrollable or excessive muscle spasms
• severe underarm sweating
• blepharospasm
• strabismus --------------?
• cerebral palsy
• Migraine
• Chronic pelvic pain
• Overactive bladder
• Tennis elbow
• Correcting facial symmetry in patients with
  facial paralysis

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Why is it necessary for multiple sessions of
Botox injections?

• The Schwann cells of the damage neuron secrete
  certain neurotrophic factors that keep the cell
  body alive and that stimulate re-growth of the
  axon
• About 10 of the population is able to generate
  antibodies to botulinum toxinthis only happens
  to people who have higher dosages at higher
  frequencies of injections (not recommended by the
  FDA)

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The re-growth of axons can be likened to the
re-growth of starfish appendages in that it is
possible if the cell body is intact.
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QUESTIONS?