Urology>>>>>Female and Functional Urology
Question 1#

Which of the following is the most predominant muscarinic receptor in the bladder?

A. M1
B. M2
C. M3
D. M4
E. M5

Correct Answer is B


Answer B

Post-ganglionic parasympathetic nerves release acetylcholine which binds to muscarinic receptors leading to detrusor contraction. There are five types of muscarinic receptors described (M1-5). M1-3 receptors are found in the bladder. Two thirds of receptors are M2 and one-third are M3. Functionally the most important muscarinic receptor is the M3 receptor, which induce entry of calcium into the cell leading to detrusor contraction even though the M2 receptor is the most commonly found one.