Botox and Tetox Flashcards
What does Botox stand for?
Botulinum toxin.
Where does Botox act in the body?
At the NMJ.
What does Botox poisoning cause?
Flaccid paralysis.
What is flaccid paralysis?
Inability to contract skeletal muscles.
How does Botox cause botulism?
Via infection with anaerobic spore-forming clostridium botulinum.
How does Botox enter cells?
After presynaptic release of NT, Botox moves into the empty vesicle. The vesicle is recycled and refilled with NT. Botox interferes with SNARE proteins (cleaves SNAP-25) to prevent vesicle fusion with the membrane.
What does the cleavage of SNAP-25 cause?
Prevents calcium-dependent exocytosis.
Name the three SNARE proteins.
Syntaxin.
Synaptobrevin.
SNAP-25.
What is the role of syntaxin?
Involved in both spontaneous and evoked NT release.
List three clinical uses for Botox.
Strabismus.
Migraine.
Cerebral palsy.
What is strabismus?
Ocular muscle spasm.
How is Botox used to treat cerebral palsy?
Can help children to walk flat on both feet by injecting Botox into the calf muscle to reduce spasticity.
Botox is an extremely potent toxin. What is the clinical advantage of this?
A very low dose is required, which will elicit little to no antibody response.
What does TeNT stand for?
Tetanus toxin.
What does TeNT cause?
Tetanus.
What is tetanus/spastic paralysis?
Uncontrolled clenching of muscles.
What are two key features of tetanus?
Trismus = lock-jaw.
Risus sardonicus = sardonic smile.
How does TeNT enter cells?
Hijacks vesicles similar to Botox to get inside the cell.
Travels in the cell body to the spinal cord.
Moves into the presynaptic terminal of a GABAergic neuron.
When the vesicle fills with NT, the pH drops.
TeNT responds to the pH drop and falls apart.
One part forms an ion channel in the vesicle.
The other part moves through the ion channel and into the cytoplasm.
It drags the ion channel through and rebuilds itself outside of the vesicle (molten globule state).
