Stimulation of the pelvic nerve increases bladder capacity in the prostaglandin E2 rat model of overactive bladder

Overactive bladder (OAB) syndrome is a highly prevalent condition that may lead to medical complications and decreased quality of life. Emerging therapies focusing on selective electrical stimulation of peripheral nerves associated with lower urinary tract function may provide improved efficacy and reduced side effects compared with sacral neuromodulation for the treatment of OAB symptoms. Prior studies investigating the effects of pelvic nerve (PelN) stimulation on lower urinary tract function were focused on promoting bladder contractions, and it is unclear whether selective stimulation of the PelN would be beneficial for the treatment of OAB. Therefore our motivation was to test the hypothesis that PelN stimulation would increase bladder capacity in the prostaglandin E-2 (PGE(2)) rat model of OAB. Cystometry experiments were conducted in 17 urethane-anesthetized female SpragueDawley rats. The effects of intravesical PGE(2) vs. vehicle and PelN stimulation after intravesical PGE(2) on cystometric parameters were quantified. Intravesical infusion of PGE(2) resulted in decreased bladder capacity and increased voiding efficiency without a change in bladder contraction area under the curve, maximum contraction pressure, or contraction duration. Bladder capacity was also significantly decreased compared with vehicle (1% ethanol in saline) confirming that the change in bladder capacity was mediated by PGE(2). PelN stimulation reversed the PGE(2)-induced change in bladder capacity and increased the external urethral sphincter electromyogram activity at a specific stimulation condition (amplitude of 1.0 times threshold at 10 Hz). These results confirm that the urodynamic changes reported in conscious rats are also observed under urethane anesthesia and that PelN stimulation is a novel and promising approach for the treatment of the symptoms of OAB.