Q. 24 - Biology

Question

Botulinum toxin causes flaccid paralysis of the muscles, and is used for cosmetic purposes under the name Botox. Which of the following is the most likely mechanism of action of Botox? 

1. Botox decreases the production of acetylcholinesterase. 
2. Botox increases calcium release from the sarcoplasmic reticulum. 
3. Botox blocks the ATP binding site in actin. 
4. Botox decreases the release of acetylcholine from motor neurons. 

Step-by-Step Solution

Answer

The correct answer is option (d).

The motor neurons' ability to release acetylcholine is decreased by Botox. 

Step : 1 Botulinum toxin

• A pure chemical generated from bacteria is botulinum toxin. 
• Botulinum toxin injections prevent the nerve signals from reaching the targeted muscle.
• By preventing the release of acetylcholine, all serotypes disrupt neuronal communication. 

Step : 2 Explanation for Correct answer

• The mechanism of action of the botulinum toxin is to prevent presynaptic motor neurons from releasing acetylcholine.
• This chemical denervation leads to a series of subsequent occurrences in the muscle that result in muscular paralysis16. 
•  A common injectable that temporarily minimizes or removes facial small lines and wrinkles is botulinum toxin's cosmetic version, also known as "Botox" by patients. Thus, the option d is correct.

Step : 3 Explanation for incorrect answer

In order to stop the release of the neurotransmitter acetylcholine, the toxin binds with a high affinity to peripheral cholinergic nerve terminals, including those in the autonomic nervous system and at the neuromuscular junction. Therefore, options a, b, and c are unsatisfactory. Due to the irrelevant nature of the selections.