Brands, Medical Use, Clinical Data
- Anti-Wrinkle Agents
- Antidystonic Agents
Brands / Synonyms
BoNT/A; Bontoxilysin A; BOTOX[Contains: Botulinum neurotoxin A light- chain, Botulinum neurotoxin A heavy-chain]; Botulinum neurotoxin type A precursor; Myobloc (Elan Corp; Solstice Neurosciences)
Neurotoxin produced by fermentation of clostridium botulinum type B. The protein exists in noncovalent association with hemagglutinin and nonhemagglutinin proteins as a neurotoxin complex. The neurotoxin complex is recovered from the fermentation process and purified through a series of precipitation and chromatography steps.
For treatment of cervical dystonia, axillary hyperhidrosis, strabismus, facial wrinkles
Myobloc inhibits acetylcholine release at the neuromuscular junction via a three stage process: 1) Heavy Chain mediated neurospecific binding of the toxin, 2) internalization of the toxin by receptor-mediated endocytosis, and 3) ATP and pH dependent translocation of the Light Chain to the neuronal cytosol where it acts as a zinc-dependent endoprotease cleaving polypeptides essential for neurotransmitter release.
Mechanism of Action
Myobloc binds to and cleaves the synaptic Vesicle Associated Membrane Protein (VAMP, also known as synaptobrevin) which is a component of the protein complex responsible for docking and fusion of the synaptic vesicle to the presynaptic membrane, a necessary step to neurotransmitter release.
Biotrnasformation / Drug Metabolism