Tag Archives: Botox Neuroscience

How does Botox Work?

The Biology of Botox

I was a neuroscience concentrator at Brown University.  So I might just call this blog the Neuroscience of Botox instead.  My wife, while at Brown, studied Biochemistry, so I might also call it the Biochemistry of Botox.  Regardless…

botox mechanism 2 botox mechanism

The main gist of what Botox does is a relaxation of muscles.  At least that’s how we view it on a grand scale.  On a more minute scale, we might see it as the prevention of release of neurotransmitters and peptides from the axon of neurons.

Mechanism of action for Botox, sequentially:

  1. Biochemical activity occurs at the neuron side (rather than the muscle) of the neuromuscular junction (NMJ)
  2. Two chain polypeptide with a heavy chain and light chain.
  3. Heavy chain of Botox targets axon terminals of neurons.
  4. After the heavy chain of Botox attaches to the surface of axon terminals, the toxin is taken into the neurons by endocytosis.
  5. The light chain is released inside the neuron cytoplasm.
  6. The light chain has protease activity and degrades the SNAP-25 protein (Synaptosomal-associated protein 25).  SNAP-25 is normally required for vesicle fusion which releases neurotransmitters from the axonal endings – usually acetylcholine (ACH).  Without the intact SNAP-25 protein, ACH is not released as a signal for muscle contraction.

 More Botox Biochemistry Notes

  • SNAP-25 is a type of SNARE protein.  SNARE stands for Soluble N-ethylmaleimide-sensitive factor attachment Protein Receptor.  SNAP 25 stands for Synaptosomal-associated protein 25.
  • Without SNAREs there is no fusion and thus no synaptic signal transfer.
  • Without acetylcholine being released the muscles no longer have their signal for contraction.  Acetylcholine is an excitatory neurotransmitter at the neuromuscular junction in skeletal muscle.

YouTube Video demonstrating the Biology of Botox

Botox on a molecular level is shown in the video above.  I did not make this video.

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Disclaimer:  There is no medical advice here.  Medical facts change from time to time, please double check these facts.

Calvin Lee, MD
Calvin Lee, MD