HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 295/4/F923    most recent 90254.2008v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Chen, S.-L. Articles by Lin, T.-B. Search for Related Content PubMed PubMed Citation Articles by Chen, S.-L. Articles by Lin, T.-B.

Acute anal stretch inhibits NMDA-dependent pelvic-urethra reflex potentiation via spinal GABAergic inhibition in anesthetized rats

Departments of ¹Urology, ³Physical Medicine and Rehabilitation, ⁴Obstetrics and Gynecology, and ¹⁰Neurology, Chung-Shan Medical University Hospital, ²Institute of Medicine and ⁶Department of Physiology, College of Medicine, Chung-Shan Medical University, ⁵Division of Urology, Department of Surgery, Taichung Veterans General Hospital, and ⁷Department of Veterinary Medicine, College of Veterinary Medicine, ⁸Department of Life Science, Chung-Hsing University, Taichung; ⁹Department of Obstetrics and Gynecology, Chung-Gang Medical University Hospital, and ¹¹Medical Department, Saint Paul's Hospital, Taoyuan; and ¹²Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan

Submitted 15 April 2008 ; accepted in final form 10 July 2008

The impact of acute anal stretch on the pelvic-urethra reflex potentiation was examined in urethane-anesthetized rats by recording the external urethra sphincter electromyogram activity evoked by the pelvic afferent stimulation. Test stimulation (1 stimulation/30 s) evoked a baseline reflex activity with a single action potential that was abolished by gallamine (5 mg/kg iv). On the other hand, the repetitive stimulation (1 stimulation/1 s) induced spinal reflex potentiation (SRP) that was attenuated by intrathecal 6-cyano-7-nitroquinoxaline-2,4-dione (a glutamatergic -amino-3-hydroxy-5-methyl-4-isoxazoleproprionat receptor antagonist, 100 µM, 10 µl) and D-2-amino-5-phosphonovalerate [a glutamatergic N-methyl-D-aspartate (NMDA) antagonist, 100 µM, 10 µl]. Acute anal stretch using a mosquito clamp with a distance of 4 mm exhibited no effect, whereas distances of 8 mm attenuated and 12 mm abolished the repetitive stimulation-induced SRP. Intrathecal NMDA (100 µM, 10 µl) reversed the abolition on SRP caused by anal stretch. On the other hand, pretreated bicuculline [-aminobutyric acid (GABA) A receptor antagonist, 100 µM, 10 µl] but not hydroxysaclofen (GABA_B receptor antagonist) counteracted the abolition on the repetitive stimulation-induced SRP caused by the anal stretch. All of the results suggested that anal stretch may be used as an adjunct to assist voiding dysfunction in patients with overactive urethra sphincter and that GABAergic neurotransmission is important in the neural mechanisms underlying external urethra sphincter activity inhibited by anal stretch.

spinal cord; voiding dysfunction; glutamate; bicuculline; hydroxysaclofen