Excitatory and Inhibitory Effects of Saphenous Nerve Stimulation on Two Different Bladder Conditons: Underactivity and Overactivity

BackgroundThis study aimed at exploring the effects of saphenous nerve stimulation (SNS) on treating both overactive bladder (OAB) and underactive bladder (UAB). MethodIn 6 -chloralose anesthetized cats, bipolar nerve cuff electrodes were implanted on the saphenous nerve and pudendal nerve. UAB was induced by pudendal nerve stimulation (PNS) at 5Hz, 2 threshold (T) and OAB was induced by infusion of 0.25% acetic acid (AA). Multiple cystometrograms (CMGs) were performed to investigate the effects of SNS on pathological bladder at 1Hz and 20Hz, respectively. ResultsApplication of PNS (5Hz, 2T) induced UAB by significantly increasing the bladder capacity (BC) to 156.3%{+/-}9.8% of control level, while combination of PNS and SNS (1Hz, 2T) applied during CMGs normalized the bladder underactivity by significantly reducing the BC to 93.6%{+/-}9.5% (P =0.026). Moreover, the BC was reduced to 64.1%{+/-}5.4% of control after infusion of AA, and SNS at 20Hz, 6T significantly increased the BC back to 93.4%{+/-}6.3% (P =0.005). No post-stimulation effect of SNS was detected at both 1Hz and 20Hz. However, there were no significant changes of contraction amplitude and duration during stimulation. ConclusionIn this study, we confirmed the frequency-dependence of SNS in regulating pathological bladder in cats. It provided experimental evidence for treating both OAB and UAB using SNS in clinic.