Experimental observations on the integration of bladder and urethral function.

Bladder and urethral pressure responses to pelvic sympathetic and pudendal nerve stimulation in 60 anesthetized cats were studied. Results show that urethral resistance is composed of smooth and skeletal muscular components, which relax with pelvic nerve stimulation. Reciprocal inhibition of the detrusor-external sphincter is a spinal-mediated reflex that can be elicited by pelvic or pudendal nerve stimulation. Urethral smooth muscular pressure loss with pelvic nerve stimulation can be blocked with propranolol, suggesting that beta-receptors are involved in this response.