Stimulation of muscarinic receptors on the bladder most directly causes which response?

Prepare for the Axonics Entrance Test. Practice with flashcards and multiple choice questions featuring detailed explanations and hints, helping you succeed in your exam!

Muscarinic receptors in the bladder primarily drive the emptying reflex. Acetylcholine from parasympathetic nerves binds mainly to M3 receptors on the detrusor smooth muscle. This activates a Gq signaling pathway that increases intracellular calcium, causing the detrusor to contract. That contraction raises bladder pressure and promotes urination. By contrast, bladder neck constriction and urine storage involve other pathways (often sympathetic control and detrusor relaxation), so muscarinic activation on the bladder does not directly cause storage or neck constriction. The direct effect of muscarinic stimulation is detrusor contraction.