Cholinergic and purinergic responses in isolated human detrusor in relation to age

PURPOSE: We investigated whether the contractility of isolated human detrusor muscle, responsiveness to commonly used spasmolytic drugs, and expression of selected muscarinic and purinergic (P2X) receptor subtypes (M2, M3, P2X1 and P2X3) change with age. MATERIALS AND METHODS: Tissues were taken from 63 patients 37 to 84 years old undergoing radical cystectomy. Specimens from 49 patients were used for contractility studies and those from 50 were used for mRNA analysis. RESULTS: Propiverine, oxybutynin, tolterodine and atropine decreased contractions evoked by electric field stimulation to different degrees. However, neither the efficacy nor potency of the drugs showed age related changes. Since human detrusor muscle shows atropine resistant noncholinergic responses, we also studied the putative age dependence of concentration-response curves to the muscarinic agonist carbachol, and the purinergic agonists adenosine triphosphate (ATP) and alpha-beta-methylene-ATP. Sensitivity to alpha-beta-methylene-ATP increased with age, while the efficacy and potency of spasmolytic drugs did not depend on age. In addition, mRNA detected for M2, M3, P2X1 and P2X3 receptors did not change with age. CONCLUSIONS: Our results do not provide evidence for age related contractile deterioration in human detrusor muscle strips, nor do they suggest that responses to anticholinergic spasmolytic drugs change substantially with age.