Supersensitivity of the rat urinary bladder following "chemical sympathectomy"

6-hydroxydopamine (100 mg/kg injected intravenously twice with a weekly interval) was used for the destruction of the adrenergic nerves in the rat detrusor muscle. Two to three weeks after the first injection of this substance the sensitivity of the detrusor muscle to parasympathomimetic and sympathomimetic drugs was tested by recording the intravesical pressure in situ. The sensitivity to methacholine was found to be unchanged, whereas a supersensitivity to noradrenaline, adrenaline, phenylephrine and isoprenaline was found to have developed, thus involving both alpha-adrenoceptor mediated contraction and beta-adrenoceptor mediated relaxation. The supersensitivity was of the postjunctional type.