Increase in presumptive sensory nerves of the urinary bladder in idiopathic detrusor instability.

The density of subepithelial, presumptive sensory nerves in the bladder wall was assessed in 21 women with idiopathic detrusor instability and compared with the density of these nerves in 21 asymptomatic women, using a point-counting technique on sections of bladder biopsies stained for acetylcholinesterase activity. The mean value (+/- S.E.) for the amount of such nerves in patients with detrusor instability (91 +/- 13/mm2) was significantly greater than that from the control group (61 +/- 7/mm2). This suggests that a relative abundance of subepithelial sensory nerves may serve to increase the appreciation of bladder filling, giving rise to the frequency and urgency of micturition which are characteristic of patients with detrusor instability.