title: Pudendal but not tibial nerve stimulation inhibits bladder contractions induced by stimulation of pontine micturition center in cats.
abstract: This study examined the possibility that pudendal nerve stimulation (PNS) or tibial nerve stimulation (TNS) inhibits the excitatory pathway from the pontine micturition center (PMC) to the urinary bladder. In decerebrate cats under α-chloralose anesthesia, electrical stimulation of the PMC (40 Hz frequency, 0.2-ms pulse width, 10-25 s duration) using a microelectrode induced bladder contractions >20 cmH2O amplitude when the bladder was filled to 60-70% capacity. PNS or TNS (5 Hz, 0.2 ms) at two and four times the threshold (2T and 4T) to induce anal or toe twitch was applied to inhibit the PMC stimulation-induced bladder contractions. Propranolol, a nonselective β-adrenergic receptor antagonist, was administered intravenously (1 mg/kg i.v.) to determine the role of sympathetic pathways in PNS/TNS inhibition. PNS at both 2T and 4T significantly (P < 0.05) reduced the amplitude and area under the curve of the bladder contractions induced by PMC stimulation, while TNS at 4T facilitated the bladder contractions. Propranolol completely eliminated PNS inhibition and TNS facilitation. This study indicates that PNS, but not TNS, inhibits PMC stimulation-induced bladder contractions via a β-adrenergic mechanism that may occur in the detrusor muscle as a result of reflex activity in lumbar sympathetic nerves. Neither PNS nor TNS activated a central inhibitory pathway with synaptic connections to the sacral parasympathetic neurons that innervate the bladder. Understanding the site of action involved in bladder neuromodulation is important for developing new therapies for bladder disorders.
authors.affiliation: Department of Urology, University of Pittsburgh, Pittsburgh, Pennsylvania;
authors.forename: Timothy D
authors.initials: TD
authors.lastname: Lyon
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: Brian T
authors.initials: BT
authors.lastname: Kadow
authors.affiliation: Department of Urology, University of Pittsburgh, Pittsburgh, Pennsylvania;
authors.forename: Richard C
authors.initials: RC
authors.lastname: Slater
authors.affiliation: Department of Urology, University of Pittsburgh, Pittsburgh, Pennsylvania; Department of Urology, Qilu Hospital, Shandong University, Jinan, People's Republic of China; and.
authors.forename: Zhaocun
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Department of Urology, University of Pittsburgh, Pittsburgh, Pennsylvania;
authors.forename: Victor
authors.initials: V
authors.lastname: Chang
authors.affiliation: Department of Urology, University of Pittsburgh, Pittsburgh, Pennsylvania;
authors.forename: Vladimir
authors.initials: V
authors.lastname: Lamm
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;
authors.forename: Jicheng
authors.initials: J
authors.lastname: Wang
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: D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D002415:Cats; D003655:Decerebrate State / Q000503:physiopathology; D004558:Electric Stimulation; D005260:Female; D008297:Male; D008839:Microelectrodes; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology; D009130:Muscle, Smooth / Q000187:drug effects / Q000502:physiology; D010275:Parasympathetic Nervous System / Q000502:physiology; D011149:Pons / Q000502:physiology*; D011433:Propranolol / Q000494:pharmacology; D060525:Pudendal Nerve / Q000502:physiology*; D013126:Spinal Nerve Roots / Q000502:physiology; D013979:Tibial Nerve / Q000502:physiology*; D001743:Urinary Bladder / Q000502:physiology*; D014554:Urination / Q000502:physiology*
chemical_list: D000319:Adrenergic beta-Antagonists; D011433:Propranolol
keywords: bladder; cat; propranolol; pudendal; tibial