Distribution of alpha- and beta-adrenoceptors in human urinary bladder

1 The distribution of alpha- and beta-adrenoceptors in isolated preparations of human bladder neck and detrusor muscle has been studied.2 Adrenaline caused contraction of the bladder neck which was blocked by phenoxybenzamine but unaltered by propranolol.3 Isoprenaline caused relaxation of the bladder neck which was blocked by propranolol. High concentrations caused contraction which was enhanced by propranolol but blocked by phenoxybenzamine.4 Detrusor muscle was relaxed by isoprenaline and this effect was blocked by propranolol. Phenylephrine caused relaxation of detrusor which was unaffected by phenoxybenzamine; in some cases contraction was produced in the presence of propranolol.5 It is concluded that the bladder neck contains mainly alpha-receptors and the detrusor mainly beta-receptors but both regions posses both types of adrenoceptor.