title: Phasic activation of the external urethral sphincter increases voiding efficiency in the rat and the cat.
abstract: OBJECTIVE
  Electrical stimulation of the pudendal nerve (PN) is a potential therapy for bladder dysfunction, but voiding efficiency (VE) produced by PN stimulation appears limited to 60-70%. We conducted experiments in rats and cats to investigate the hypothesis that introduction of artificial phasic bursting activity of the external urethral sphincter (EUS) would enhance VE under conditions where such activity was absent.
  
  
  METHODS
  Cystometry experiments were conducted in 17 urethane anesthetized female Sprague-Dawley rats and 4 α-chloralose anesthetized male cats. The effects of phasic stimulation of the pudendal motor branch on VE were quantified in intact conditions, following bilateral transection of the motor branch of the PN, and following subsequent bilateral transection of the sensory branch of the PN.
  
  
  RESULTS
  Artificial phasic bursting activity in the EUS generated by electrical stimulation of the motor branch of the PN increased VE in both rats and cats. Subsequent transection of the sensory branch of the PN abolished the increased VE elicited by phasic stimulation in both rats and cats.
  
  
  CONCLUSIONS
  Artificial phasic EUS bursting restored efficient voiding in rats. Introduction of artificial phasic bursting in cats, which normally exhibit EUS relaxation while voiding, was also effective in promoting efficient voiding. In both species phasic EUS activity increased voiding efficiency via activation of pudendal sensory pathways. These results provide further insight into the function of phasic EUS activity in efficient voiding and highlight a novel approach to increase VE generated by pudendal afferent nerve stimulation.
authors.affiliation: Department of Biomedical Engineering, Duke University, Durham, NC, USA.
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Langdale
authors.affiliation: Department of Biomedical Engineering, Duke University, Durham, NC, USA; Department of Electrical and Computer Engineering, Duke University, Durham, NC, USA; Department of Neurobiology, Duke University, Durham, NC, USA; Department of Surgery, Duke University, Durham, NC, USA. Electronic address: warren.grill@duke.edu.
authors.forename: Warren M
authors.initials: WM
authors.lastname: Grill
mesh_terms: D000344:Afferent Pathways / Q000502:physiology; D000704:Analysis of Variance; D000818:Animals; D002415:Cats; D004558:Electric Stimulation; D004576:Electromyography; D019054:Evoked Potentials, Motor / Q000502:physiology; D005260:Female; D008297:Male; D009119:Muscle Contraction / Q000502:physiology; D060525:Pudendal Nerve / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014521:Urethra / Q000502:physiology*; D001743:Urinary Bladder / Q000294:innervation; D014554:Urination / Q000502:physiology*
keywords: Augmentation reflex; Bladder; Deep perineal nerve; Electrical stimulation; Micturition; Pudendal-pudendal reflex