Botox (OnabotulinumtoxinA) inhibits the release which of the following?

a. Serotonin
b. Histamine
c. Acetylcholine
e. Dopamine

The active ingredient found in Botox is OnabotulinumtoxinA. It is an acetylcholine release inhibitor and a neuromuscular blocking agent.

Botox (OnabotulinumtoxinA) blocks neuromuscular transmission by binding to acceptor sites on motor or autonomic nerve terminals, entering the nerve terminals, and inhibiting the release of acetylcholine. This inhibition occurs as the neurotoxin cleaves SNAP-25, a protein integral to the successful docking and release of acetylcholine from vesicles situated within nerve endings.

When injected intramuscularly at therapeutic doses, Botox (OnabotulinumtoxinA) produces partial chemical denervation of the muscle resulting in a localized reduction in muscle activity. In addition, the muscle may atrophy, axonal sprouting may occur, and extrajunctional acetylcholine receptors may develop. There is evidence that reinnervation of the muscle may occur, thus slowly reversing muscle denervation produced by Botox (OnabotulinumtoxinA).

When injected intradermally, Botox (OnabotulinumtoxinA) produces temporary chemical denervation of the sweat gland resulting in local reduction in sweating.

Following intradetrusor injection, Botox (OnabotulinumtoxinA) affects the efferent pathways of detrusor activity via inhibition of acetylcholine release.

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