Question

Botox blocks synaptosomal-associated protein 25 (SNAP-25), a protein that promotes synaptic vesicle fusion. The mechanism by which Botox can temporarily reduce the formation of wrinkles in the face is most directly due to which of the following?

Locally blocking the release of synaptic transmitter from motor neurons

Preventing the opening of sodium channels on muscle membranes

Decreasing the amount of calcium released from the sarcoplasmic reticulum

Enhancing the enzymatic hydrolysis of acetylcholine at the neuromuscular junction

Answer 1

Botox reduces wrinkles by blocking the release of acetylcholine from motor neurons, leading to muscle relaxation in the face.

Step-by-step explanation:

The mechanism by which Botox can temporarily reduce the formation of wrinkles in the face is most directly due to locally blocking the release of synaptic transmitter from motor neurons. Botox, a neurotoxin produced by Clostridium botulinum, works by inhibiting the release of acetylcholine, a neurotransmitter that signals muscles to contract. By preventing the release of acetylcholine at the neuromuscular junction, Botox causes a temporary relaxation of the facial muscles, thereby smoothing wrinkles.

It does not prevent the opening of sodium channels on muscle membranes, decrease the amount of calcium released from the sarcoplasmic reticulum, or enhance the hydrolysis of acetylcholine. Therefore, Botox specifically targets the synaptic process to achieve muscle relaxation, resulting in the cosmetic benefit of reducing facial wrinkles.