This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: A.N.S., Subject name: Pharmacology
[{'content': 'Botulinum toxin acts on: \nSelect and explain. \nA. Inhibition of release of neurotransmitter, B. Post synaptic block, C. At synapse, D. Reuptake inhibitor', 'role': 'user'}, {'content': "Answer: A \nExplanation: (Ref: KD Tripathi, 7th ed. pg. 99)Release of Ach from nerve terminals occurs in small quanta--amount contained in individual vesicles is extruded by exocytosis.Two toxins interfere with cholinergic transmission by affecting release:# Botulinum toxin inhibits release# Black widow spider toxin induces massive release and depletionBotulinum toxin# Botulinum toxin A and B are highly potent exotoxins produced by Clostridium botulinum that are responsible for 'botulism' (a type of food poisoning). These neurotoxic proteins cause long-lasting loss of cholinergic transmission by interacting with axonal proteins involved in exocytotic release of Ach.", 'role': 'assistant'}]