title: Somatomotor and sensory urethral control of micturition in female rats.
abstract: In rats, axons of external urethral sphincter (EUS) motoneurons travel through the anastomotic branch of the pudendal nerve (ABPD) and anastomotic branch of the lumbosacral trunk (ABLT) and converge in the motor branch of the sacral plexus (MBSP). The aim of the present study was to determine in female rats the contribution of these somatomotor pathways and urethral sensory innervation from the dorsal nerve of the clitoris on urinary continence and voiding. EUS electromyographic (EMG) activity during cystometry, leak point pressure (LPP), and voiding efficiency (VE) were assessed in anesthetized virgin Sprague-Dawley female rats before and after transection of the above nerve branches. Transection of the MBSP eliminated EUS EMG, decreased LPP by 50%, and significantly reduced bladder contraction duration, peak pressure, intercontraction interval, and VE. Transection of the ABPD or ABLT decreased EUS EMG discharge and LPP by 25% but did not affect VE. Transection of the dorsal nerve of the clitoris did not affect LPP but reduced contraction duration, peak pressure, intercontraction interval, and VE. We conclude that somatomotor control of micturition is provided by the MBSP with axons travelling through the ABPD and ABLT. Partial somatomotor urethral denervation induces mild urinary incontinence, whereas partial afferent denervation induces voiding dysfunction. ABPD and ABLT pathways could represent a safeguard ensuring innervation to the EUS in case of upper nerve damage. Detailed knowledge of neuroanatomy and functional innervation of the urethra will enable more accurate animal models of neural development, disease, and dysfunction in the future.
authors.affiliation: Centro Tlaxcala Biología de la Conducta, Universidad Autónoma de Tlaxcala, Tlaxcala, México;
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Cruz
authors.affiliation: Centro Tlaxcala Biología de la Conducta, Universidad Autónoma de Tlaxcala, Tlaxcala, México; Doctorado en Neuroetología, Universidad Veracruzana, Xalapa, Veracruz, México;
authors.forename: César
authors.initials: C
authors.lastname: Pastelín
authors.affiliation: Department of Biomedical Engineering, Cleveland Clinic, Cleveland, Ohio;
authors.forename: Brian M
authors.initials: BM
authors.lastname: Balog
authors.affiliation: Advanced Platform Technology Center, Louis Stokes Veterans Affairs Medical Center, Cleveland, Ohio; and.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Zaszczurynski
authors.affiliation: Department of Biomedical Engineering, Cleveland Clinic, Cleveland, Ohio; Advanced Platform Technology Center, Louis Stokes Veterans Affairs Medical Center, Cleveland, Ohio; and Glickman Urological and Kidney Institute, Cleveland Clinic, Cleveland, Ohio damasem@ccf.org.
authors.forename: Margot S
authors.initials: MS
authors.lastname: Damaser
mesh_terms: D000818:Animals; D002987:Clitoris / Q000294:innervation; D005260:Female; D008160:Lumbosacral Plexus / Q000502:physiology; D011312:Pressure; D060525:Pudendal Nerve / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D014521:Urethra / Q000294:innervation / Q000502:physiology*; D014549:Urinary Incontinence / Q000503:physiopathology; D014554:Urination / Q000502:physiology*; D014563:Urodynamics / Q000502:physiology
keywords: external urethral sphincter; neuroanatomy; neurourology; pudendal nerve; stress urinary incontinence