Question

Which one of the following interferes with the release of cholingeric neurotransmitter, acetylcholine by the neurons of autonomic nervous system?

• A. Reserpine
• B. Guanethidine
• C. Hemicholinium
• D. Botulinum toxin

Answer 1

The Correct Option is D

To determine which substance interferes with the release of the cholinergic neurotransmitter, acetylcholine, by neurons of the autonomic nervous system, we need to examine how each option affects neurotransmission:

1. Reserpine: This drug interferes with the storage of neurotransmitters like norepinephrine, dopamine, and serotonin in vesicles of presynaptic neurons. It primarily affects adrenergic neurons and has little to no direct effect on the release of acetylcholine.
2. Guanethidine: This drug prevents the release and uptake of norepinephrine by targeting adrenergic neurons. Similar to reserpine, it does not directly inhibit acetylcholine release.
3. Hemicholinium: This compound inhibits the uptake of choline, which is a precursor in the synthesis of acetylcholine. While it can affect acetylcholine production indirectly by depleting choline stores, it does not inhibit the release of acetylcholine.
4. Botulinum toxin: This neurotoxin specifically blocks the release of acetylcholine at the neuromuscular junction and autonomic synapses. It achieves this by cleaving proteins essential for the vesicular release process of acetylcholine, effectively preventing neurotransmission and inducing muscle paralysis.

Conclusion: Botulinum toxin directly interferes with the release of acetylcholine by cleaving synaptic proteins necessary for the fusion of synaptic vesicles with the neuron membrane. Thus, the correct answer is Botulinum toxin.