Neuromodulation attenuates bladder hyperactivity in a rat cystitis model

We investigated the regulation of urinary bladder function by electrical stimulation of the L6 spinal nerve (SN) using cystometry in normal rats and in rats with cystitis induced by intravesical infusion of dilute acetic acid. In anesthetized rats, a cannula was placed into the bladder dome for saline/acetic acid infusion and intravesical pressure monitoring. Threshold pressure (TP), basal pressure (BP) and inter-contraction interval (ICI) were measured from the bladder pressure recording and void volume (VV) was measured by weighing the voided fluid. Comparison of cystometrograms obtained with infusion of saline or acetic acid showed that acetic acid decreases TP, ICI and VV. These excitatory effects, characteristic of acetic acid induced bladder hyperactivity, were significantly reversed by bilateral SN stimulation (P