The Mechanism of Botox in Wrinkles Reduction
Figure 1:Binding of BT-A with receptors on plasma membrane
Figure 2:Endocytosis of BT-A into motor nerve cytoplasm
All the images above adopted from:
Figure 4: Difference in the neuromuscular junction after botox injection. Notice that the acetylcholine is no longer released into end plate region after injection. (Image adopted from emedicine.com)
Click on the video below to view how botox inhibit muscle contraction.
(Video adopted from youtube.com)
Generally, the Botox or BT-A works by weakens or paralyzes muscles by inhibiting the release of acetylcholine. Soon after the Botox is injected,
Figure 1:Binding of BT-A with receptors on plasma membrane
1.0 The heavy chain of the BT-A bind irreversible with specific receptors called sialoglycoproteins in the plasma membrane of motor nerve.
1.1 The binding allows efficient uptake of Botox by the motor nerve and facilitates selective targeted treatment at the injection site.
Figure 2:Endocytosis of BT-A into motor nerve cytoplasm
2.0 The binding induces receptor-mediated endocytosis of the toxin where the Botox molecule passes through the cell membrane of the motor nerve and into its cytoplasm.
2.1 The light chain of BT-A that is responsible for the toxicity is activated and split off in the cell.
(This is due to the fact that the subunit of BT-A are linked together by only single disulphide bond, the BT-A is therefore unstable and can break down into inactive subunits as a result of minimal mechanical and thermal stresses. )
(This is due to the fact that the subunit of BT-A are linked together by only single disulphide bond, the BT-A is therefore unstable and can break down into inactive subunits as a result of minimal mechanical and thermal stresses. )
Figure3: Inactivation of SNAP 25
3.0 Light chain of Botox cleaves apart a synapse-specific protein, synaptosomal-associated protein of 25kDa( SNAP25) that enable neurotransmitter acetylcholine storing vesicles to attach to cell membrane.
3.1 SNAP-25 is inactivated from a fusion complex of three proteins.
All the images above adopted from:
Allergan Incorporation. 2010. Mechanism of Action.
4. Cleaving SNAP25 prevents acetylcholine storing vesicles from fusing with the membrane and prevents the release of acetylcholine into the neuromuscular junction (the space between the motor nerve and the muscle).
As Acetylcholine act as chemical trigger of ion channel, inhibiting the release of acetylcholine causes blockage in transmission of the nerve impulses to neuromuscularjunction and myoneural (muscle-nerve) junctions. Thus, muscle cannot contract and the muscle activity decreases. (P. Becker-Wegerich, L. Rauch and T. Ruzicka. 2001.)
Click on the video below to view how botox inhibit muscle contraction.
(Video adopted from youtube.com)
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