Urinary bladder innervation in children.

Muscle strips from the fundus, trigone, and distal ureter obtained from children at operation for vesicoureteric reflux were studied using histochemical and immunohistochemical methods, and electrical nerve stimulation in an organ bath. A rich supply of cholinergic nerves was found and the transmitter causing contraction of the detrusor muscle was regarded as being acetylcholine. The adrenergic innervation was very sparse except around the ureteric orifices. No contractile alpha-adrenoceptors could be detected but beta-receptor-mediated relaxation was found. The type was not beta 1 or beta 2, suggesting a third type of beta-receptor. Peptidergic nerves containing vasoactive intestinal peptide (VIP) were demonstrated in a few nerve terminals. No nerves containing enkephalin, somatostatin, or substance P were found. VIP affected the detrusor muscle, indicating a possible role as a modulator of transmitter action. Imipramine, used for enuresis, had no anticholinergic effect on the bladder in the doses used clinically. The anticholinergic and calcium antagonistic drug terodiline inhibited all muscle activity, making it suitable for treatment of diurnal enuresis.