MP8-18 THE ROLE OF THE BRAINSTEM IN TIBIAL INHIBITION OF THE MICTURITION REFLEX IN CATS

Abstract

You have accessJournal of UrologyUrodynamics/Incontinence/Female Urology: Basic Research I1 Apr 2015MP8-18 THE ROLE OF THE BRAINSTEM IN TIBIAL INHIBITION OF THE MICTURITION REFLEX IN CATS Matthew Ferroni, Richard Slater, Bing Shen, Zhiying Xiao, Jicheng Wang, Andy Lee, James Roppolo, William de Groat, and Changfeng Tai Matthew FerroniMatthew Ferroni More articles by this author , Richard SlaterRichard Slater More articles by this author , Bing ShenBing Shen More articles by this author , Zhiying XiaoZhiying Xiao More articles by this author , Jicheng WangJicheng Wang More articles by this author , Andy LeeAndy Lee More articles by this author , James RoppoloJames Roppolo More articles by this author , William de GroatWilliam de Groat More articles by this author , and Changfeng TaiChangfeng Tai More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2015.02.285AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Tibial Nerve Stimulation (TNS) has been shown to significantly inhibit the micturition reflex when the bladder is distended by saline infusion or irritated by 0.25% acetic acid (AA) in cats. However, TNS inhibition of AA-induced bladder overactivity is lost after acute spinal cord transection at the level of T9/T10 indicating a supraspinal site of action. This study determines the role of the brainstem in TNS inhibition, which is important for understanding the mechanism of action of tibial neuromodulation therapy for overactive bladder. METHODS 16 cats under isoflurane anesthesia underwent decerebration by surgical transection rostral to the superior colliculi. Then, multiple saline cystometrograms (CMGs) were performed under á-chloralose anesthesia to elicit micturition reflex contractions (>30 cmH2O). 30 minutes of continuous TNS at three times threshold intensity for inducing toe movement was then applied during isovolumetric bladder contractions at frequencies of either 5Hz or 30Hz. After each stimulation, five consecutive CMGs were performed to assess post-stimulation changes of bladder capacity. CMGs were then performed during TNS at either 5Hz or 30Hz. Next, the same stimulation protocol was repeated during AA irritation. At the end of each experiment, naloxone (an opioid receptor antagonist) was administered either intravenously (1 mg/kg) or directly into the brainstem (2.0-4.0 mg in 0.1-0.2 cc) followed by a series of CMGs with/without TNS. ANOVA tests were used to determine statistical significance (p<0.05). RESULTS During saline infusion, 30 minutes of TNS significantly increased post-stimulation bladder capacity above controls with a mean increase of 27.2% (p<0.01) at a frequency of 5 Hz and 44.2% (p<0.01) at a frequency of 30 Hz. However, post-stimulation TNS inhibition was not observed during AA infusion. TNS applied during CMG significantly increased bladder capacity by 27.3% (saline, p<0.01) and 87.6% (AA, p<0.01) respectively over controls at 5 Hz, but failed to achieve significant inhibition at 30 Hz. Naloxone treatments significantly reduced control bladder capacity whether given intravenously (68.1% reduction, p<0.01) or directly into brainstem (58.8% reduction, p<0.01) and completely eliminated the acute TNS inhibition. CONCLUSIONS Our results suggest: (1) the brainstem plays an important role in TNS inhibition of both non-nociceptive (saline distention) and nociceptive (AA irritation) bladder reflexes while the cerebrum is not necessary; (2) opioid receptors in the brainstem are involved in TNS inhibition of the nociceptive bladder reflex. © 2015 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 193Issue 4SApril 2015Page: e79-e80 Advertisement Copyright & Permissions© 2015 by American Urological Association Education and Research, Inc.MetricsAuthor Information Matthew Ferroni More articles by this author Richard Slater More articles by this author Bing Shen More articles by this author Zhiying Xiao More articles by this author Jicheng Wang More articles by this author Andy Lee More articles by this author James Roppolo More articles by this author William de Groat More articles by this author Changfeng Tai More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...