Action of Drugs on the Innervated and Denervated Urinary Bladder of the Rat

Abstract

Abstract In the normally innervated rat bladder methacholine, acetylcholine, adrenaline and phenylephrine elicited contraction of the detrusor muscle in situ, while isoprenaline caused relaxation. The response to noradrenaline varied but was most often relaxation. Experiments with dihydroergotamine and propranolol indicated the presence of both excitatory a‐receptors and inhibitory β‐receptors in the detrusor muscle. The bladder developed supersensitivity to parasympathomimetic agents and in the case of a‐receptor mediated effects also to sympathomimetic agents after parasympathetic decentralization and denervation, and after sympathetic denervation. Regarding the adrenergic β‐receptor effects, however, no supersensitivity developed after any of the denervation procedures. Parasympathetic denervation or decentralization uncovered a contractile response to noradrenaline most often masked by predominant relaxation in the normal bladder.