title: The impact of discrete modes of spinal cord injury on bladder muscle contractility.
abstract: BACKGROUND
  Prior studies have compared the effect of spinal cord injury elicited using distinct approaches on motor and visceral function. However, the impact of such discrete modes of injury specifically on bladder muscle contractility has not been explored in detail. The goal of this study is to compare the impact of complete spinal cord transection versus clip compression at thoracic vertebra eight (T8) on bladder muscle contractility.
  
  
  METHODS
  Rats underwent no treatment (Control), laminectomy (Sham, SH); complete extradural transection (TX); or cord compression with an aneurysm clip (CX). Bladders and spinal cords were harvested at 6 wk for contractility studies or histological analysis.
  
  
  RESULTS
  Detrusor strips from TX and CX rats showed higher spontaneous activity than those from SH rats. Furthermore, the duration of the neurally-mediated contractile response was longer in TX and CX rats compared to controls and showed attenuated relaxation. No significant differences were observed between muscle strips from SH, TX or CX rats in response to KCl, ATP or phenylephrine. However, tissues from TX and CX rats showed a higher sensitivity to carbachol compared to that from SH animals.
  
  
  CONCLUSIONS
  Complete SCI in rats either by cord transection or compression elicits qualitatively similar changes in bladder muscle contractility. Whereas cord transection is arguably easier to perform experimentally, cord compression better models the situation observed clinically, such that each approach has clear advantages and limitations.
authors.affiliation: Urological Diseases Research Center, Boston Children's Hospital, Boston, MA 02115, USA.
authors.forename: Abhishek
authors.initials: A
authors.lastname: Seth
authors.forename: Yeun Goo
authors.initials: YG
authors.lastname: Chung
authors.forename: Daniel
authors.initials: D
authors.lastname: Kim
authors.forename: Aruna
authors.initials: A
authors.lastname: Ramachandran
authors.forename: Vivian
authors.initials: V
authors.lastname: Cristofaro
authors.forename: Pablo
authors.initials: P
authors.lastname: Gomez
authors.forename: Duong
authors.initials: D
authors.lastname: Tu
authors.forename: Lin
authors.initials: L
authors.lastname: Huang
authors.forename: Larry I
authors.initials: LI
authors.lastname: Benowitz
authors.forename: Dolores
authors.initials: D
authors.lastname: Di Vizio
authors.forename: Maryrose P
authors.initials: MP
authors.lastname: Sullivan
authors.forename: Rosalyn M
authors.initials: RM
authors.lastname: Adam
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D006801:Humans; D007796:Laminectomy; D008297:Male; D009119:Muscle Contraction; D009130:Muscle, Smooth / Q000503:physiopathology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013045:Species Specificity; D013117:Spinal Cord Compression / Q000503:physiopathology*; D013119:Spinal Cord Injuries / Q000503:physiopathology*; D001743:Urinary Bladder / Q000503:physiopathology*