title: Role of the brain stem in tibial inhibition of the micturition reflex in cats.
abstract: This study examined the role of the brain stem in inhibition of bladder reflexes induced by tibial nerve stimulation (TNS) in α-chloralose-anesthetized decerebrate cats. Repeated cystometrograms (CMGs) were performed by infusing saline or 0.25% acetic acid (AA) to elicit normal or overactive bladder reflexes, respectively. TNS (5 or 30 Hz) at three times the threshold (3T) intensity for inducing toe movement was applied for 30 min between CMGs to induce post-TNS inhibition or applied during the CMGs to induce acute TNS inhibition. Inhibition was evident as an increase in bladder capacity without a change in amplitude of bladder contractions. TNS applied for 30 min between saline CMGs elicited prolonged (>2 h) poststimulation inhibition that significantly (P < 0.05) increased bladder capacity to 30-60% above control; however, TNS did not produce this effect during AA irritation. TNS applied during CMGs at 5 Hz but not 30 Hz significantly (P < 0.01) increased bladder capacity to 127.3 ± 6.1% of saline control or 187.6 ± 5.0% of AA control. During AA irritation, naloxone (an opioid receptor antagonist) administered intravenously (1 mg/kg) or directly to the surface of the rostral brain stem (300-900 μg) eliminated acute TNS inhibition and significantly (P < 0.05) reduced bladder capacity to 62.8 ± 22.6% (intravenously) or 47.6 ± 25.5% (brain stem application). Results of this and previous studies indicate 1) forebrain circuitry rostral to the pons is not essential for TNS inhibition; and 2) opioid receptors in the brain stem have a critical role in TNS inhibition of overactive bladder reflexes but are not involved in inhibition of normal bladder reflexes.
authors.affiliation: Department of Urology, University of Pittsburgh, Pittsburgh, Pennsylvania;
authors.forename: Matthew C
authors.initials: MC
authors.lastname: Ferroni
authors.affiliation: Department of Urology, University of Pittsburgh, Pittsburgh, Pennsylvania;
authors.forename: Rick C
authors.initials: RC
authors.lastname: Slater
authors.affiliation: Department of Urology, University of Pittsburgh, Pittsburgh, Pennsylvania;
authors.forename: Bing
authors.initials: B
authors.lastname: Shen
authors.affiliation: Department of Urology, University of Pittsburgh, Pittsburgh, Pennsylvania; Department of Urology, The Second Hospital, Shandong University, Jinan, P.R. China; and.
authors.forename: Zhiying
authors.initials: Z
authors.lastname: Xiao
authors.affiliation: Department of Urology, University of Pittsburgh, Pittsburgh, Pennsylvania;
authors.forename: Jicheng
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Urology, University of Pittsburgh, Pittsburgh, Pennsylvania;
authors.forename: Andy
authors.initials: A
authors.lastname: Lee
authors.affiliation: Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors.forename: James R
authors.initials: JR
authors.lastname: Roppolo
authors.affiliation: Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors.forename: William C
authors.initials: WC
authors.lastname: de Groat
authors.affiliation: Department of Urology, University of Pittsburgh, Pittsburgh, Pennsylvania; Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania cftai@pitt.edu.
authors.forename: Changfeng
authors.initials: C
authors.lastname: Tai
mesh_terms: D019342:Acetic Acid; D000818:Animals; D001933:Brain Stem / Q000502:physiology*; D002415:Cats; D003655:Decerebrate State / Q000503:physiopathology; D004558:Electric Stimulation; D005260:Female; D008297:Male; D009270:Naloxone / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology; D060525:Pudendal Nerve / Q000187:drug effects; D012018:Reflex / Q000502:physiology*; D013979:Tibial Nerve / Q000502:physiology*; D001743:Urinary Bladder / Q000294:innervation / Q000503:physiopathology; D053201:Urinary Bladder, Overactive / Q000139:chemically induced / Q000503:physiopathology; D014554:Urination / Q000502:physiology*
chemical_list: D009292:Narcotic Antagonists; D009270:Naloxone; D019342:Acetic Acid
keywords: brain stem; cat; neuromodulation; opioid; tibial