A 58-year-old woman with narrow-angle glaucoma is prescribed pilocarpine eye drops. Which receptor subtype mediates the reduction in intraocular pressure produced by pilocarpine?
- A M3 receptor ✓
- B Beta-2 receptor
- C Alpha-1 receptor
- D Nicotinic neuronal (Nn) receptor
Correct answer: A. M3 receptor
Explanation
Pilocarpine is a direct-acting muscarinic agonist. Contraction of the ciliary muscle via M3 receptors opens the trabecular meshwork, facilitating aqueous humor outflow and reducing intraocular pressure. It also contracts the sphincter pupillae (M3) to produce miosis, which pulls the iris away from the drainage angle.
Reference: Katzung's Basic and Clinical Pharmacology, 15th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.