Bladder inhibition or excitation by electrical perianal stimulation in a cat model of chronic spinal cord injury.
OBJECTIVE
To test the hypothesis that perianal electrical stimulation (PES) in chronic spinal cord-injured (SCI) cats could induce frequency-dependent inhibitory or excitatory reflex bladder responses.


METHODS
The experiments were conducted > or =4-5 weeks after spinal cord transection at the T9-T10 level. PES was applied via a pair of hook electrodes to the perianal skin area in three awake female cats with chronic SCI. A double-lumen balloon catheter was inserted through the urethra into the bladder to monitor bladder pressure and infuse saline (2-4 mL/min).


RESULTS
Under isovolumetric conditions PES at 3-10 Hz significantly inhibited large-amplitude reflex bladder activity induced by bladder distension above the micturition volume threshold. However, PES at 20-50 Hz induced large-amplitude bladder contractions when the bladder volume was below the micturition volume threshold. Inhibitory PES (7 Hz) significantly increased the mean (sem) bladder capacity by 40 (10)% when it was applied continuously during cystometrography. The optimum excitatory PES (30 Hz) induced large-amplitude (>25 cmH(2)O), long-duration (>20 s) bladder contractions at a wide range of bladder volumes (10-90% of bladder capacity).


CONCLUSIONS
This study showed that activation of pudendal afferent fibres by PES could induce frequency-dependent reflex bladder responses in awake cats with chronic SCI, indicating that a possible noninvasive treatment based on PES could be developed to restore both continence and micturition function for patients with SCI.
Wang
Jicheng
J
Department of Urology, University of Pittsburgh, Pittsburgh, PA 15261, USA.
Liu
Hailong
H
Shen
Bing
B
Roppolo
James R
JR
de Groat
William C
WC
Tai
Changfeng
C
D000344:Afferent Pathways / Q000502:physiology; D000818:Animals; D002415:Cats; D004599:Electric Stimulation Therapy; D005260:Female; D009119:Muscle Contraction / Q000502:physiology; D009130:Muscle, Smooth / Q000502:physiology; D010525:Peripheral Nerves / Q000502:physiology*; D012018:Reflex / Q000502:physiology; D013119:Spinal Cord Injuries / Q000503:physiopathology* / Q000628:therapy; D001743:Urinary Bladder / Q000294:innervation / Q000502:physiology*; D014554:Urination / Q000502:physiology