This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Autonomic nervous system, Subject name: Pharmacology
[{'content': 'The most impoant action of beta-blockers in glaucoma is : \nSelect and explain. \nA. Membrane stabilizing effect, B. Refinal neuron protecting effect, C. Decrease in the production of aqueous humor, D. Pupillary constriction', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ref: KD Tripathi pharmacology 7th edition (page.no: 144) Topical b blockers are one of the first-line drug for glaucoma In contrast to miotics, the b blockers do not affect pupil size, the tone of ciliary muscle or outflow facility, but lower i.o.t. by reducing aqueous formation. This probably results from down-regulation of adenylyl cyclase due to b 2 receptor blockade in the ciliary epithelium and a secondary effect due to a reduction in ocular blood flow.', 'role': 'assistant'}]