Time-Frequency Analysis of Increases in Vaginal Blood Perfusion Elicited by Long-Duration Pudendal Neuromodulation in Anesthetized Rats

Objectives Female sexual dysfunction (FSD) affects a significant portion of the population. Although treatment options for FSD are limited, neuromodulation for bladder dysfunction has improved sexual function in some women. A few studies have investigated peripheral neuromodulation for eliciting changes in vaginal blood flow, as a proxy for modulating genital sexual arousal, however results are generally transient. Our central hypothesis is that repeated or extended-duration pudendal nerve stimulation can elicit maintained vaginal blood flow increases. Materials and Methods Under ketamine anesthesia, the pudendal nerve of 14 female rats was stimulated at varying frequencies (1–100 Hz) and durations (0.15–60 min). Vaginal blood perfusion was measured with a laser Doppler flowmetry probe. Changes in blood perfusion were determined through raw signal analysis and increases in the energy of neurogenic (0.076–0.200 Hz) and myogenic (0.200–0.740 Hz) frequency bands through wavelet analysis. Additionally, a convolution model was developed for a carry-over stimulation effect. Results Each experiment had significant increases in vaginal blood perfusion due to pudendal nerve stimulation. In addition, there were large concurrent increases in neurogenic and myogenic frequency-band energy in 11/14 experiments, with an average maximal response at 31.3 min after stimulation initiation. An effective stimulation model with a 30-min carry-over effect had a stronger correlation to blood perfusion than the stimulation period itself. Conclusions Repeated or extended-duration pudendal nerve stimulation can elicit maintained increases in vaginal blood perfusion. This work indicates the potential for pudendal neuromodulation as a method for increasing genital arousal as a potential treatment for FSD.