Lumbosacral ventral root avulsion alters reflex activation of bladder, urethra, and perineal muscles during micturition in female rabbits

Abstract

Aim To determine the effect of the lumbosacral ventral root avulsion (VRA) on the reflex activation of bladder, urethra, and activation of perineal muscles during micturition in female rabbits. Methods We allocated 14 virgin female rabbits to evaluate, first, the gross anatomy of lumbosacral spinal cord root (n = 5) and, second, to determine the effect of VRA on perineal muscles during micturition (n = 9). We recorded cystometrograms, urethral pressure, and electromyograms of the bulbospongiosus (Bsm) and ischiocavernosus (Ism) muscles before and after the L6‐S2 VRA. Standard variables were measured from each recording and analyzed to identify significant differences (P < .05). Results We found that the L6‐S2 VRA affected directly the bladder and urethral function and reduced the duration and the frequency of the bursting of Ism and Bsm muscles during voiding. The Ism and Bsm showed a phasic activation, of different frequencies, during the voiding phase and the L6‐S2 VRA inhibited the co‐contraction of the Ism and Bsm‐bladder‐urethra. Conclusions The Ism and Bsm are activated at different frequencies to trigger the voiding phase. The L6‐S2 VRA affected the activity pattern of both perineal muscles. These modifications affected the bladder and urethra function. It is possible that the restoration of the activation frequency of perineal muscles contributed for an efficient bladder contraction.

Estrogens influence differentially on the pelvic floor muscles activation at somatovisceral reflexes involved in micturition of rabbits

“…We also obtained the power spectral density (PSD) from EMGs of the Pcm and Bsm through the fast Fourier transform filtered with Hamming windowing to help avoid distortion of the fast Fourier transform plot caused by the discontinuous start and stop of the data. 25 We sampled 11second windows (epochs) at the end of the storage, preceding voiding, during the voiding phase, around the MP, and at the resuming of the storage phase of the four micturition cycles per female rabbit. We calculated the mean power (MeanP) and the median of frequencies (MedianF) for each epoch and all groups.…”