Fig. 3.
Innervation of the lower urinary tract: The parasympathetic pelvic nerve stimulates the bladder detrusor muscle, mediated by muscarinic receptors (M3) being activated by ACh. The sympathetic hypogastric nerve stimulates urethral smooth muscle and inhibits bladder detrusor, mediated by α1-adrenergic and β3-adrenergic receptors, respectively. The somatic pudendal nerve stimulates striated muscle of the EUS, mediated by ACh activating nicotinic (N) receptors. ACh, acetylcholine; NE, norepinephrine. Plus and minus signs indicate neural stimulation and inhibition, respectively.