title: Propagation of the electrical impulse in reversible unilateral ureteral obstruction as determined at high electrophysiological resolution.
abstract: OBJECTIVE
  We investigated the propagation of electrical impulses in a reversible, complete or partial unilateral ureteral obstruction model in vivo.
  
  
  METHODS
  In Wistar rats the left mid ureter was completely (8) or partially (7) occluded and released after 24 hours. We recorded electrical activity of the left and right ureter before, during and after obstruction at different stages up to 2 weeks after obstruction using a high resolution, 64 extracellular electrode probe.
  
  
  RESULTS
  Complete obstruction in the left proximal ureter caused an immediate increase in frequency from a mean ± SEM of 14.8 ± 1.3 to 18.6 ± 1.7 per minute (p <0.05), followed by a 1.4 ± 0.9 per minute decrease (p <0.001). Within the first 2 days after reversal velocity gradually decreased from 1.82 ± 0.12 to 0.79 ± 0.17 cm per second (p <0.001). Release of obstruction gradually restored frequency and velocity, which returned to baseline at 2 weeks. Generally the alterations in rats with complete and partial obstruction were similar but they were less marked in those with partial obstruction. Distal to the obstruction site the impulses disappeared (38%) or propagated retrograde (43%) at some stage in the post-obstruction period. These abnormal impulse propagations also gradually disappeared in the post-obstruction stage.
  
  
  CONCLUSIONS
  After complete or partial ureteral obstruction there were immediate, significant changes in the propagation of electrical impulses in the proximal and distal left ureter, which were generally less marked after partial than after complete obstruction. Reversal of obstruction resulted in the gradual disappearance of this abnormality in 2 weeks.
authors.affiliation: Department of Surgery, Faculty of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates. fayez@mail2doctor.com
authors.forename: Fayez T
authors.initials: FT
authors.lastname: Hammad
authors.forename: Wim J
authors.initials: WJ
authors.lastname: Lammers
authors.forename: Betty
authors.initials: B
authors.lastname: Stephen
authors.forename: Loay
authors.initials: L
authors.lastname: Lubbad
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D004195:Disease Models, Animal; D004553:Electric Conductivity; D004558:Electric Stimulation; D004576:Electromyography; D004594:Electrophysiology; D008297:Male; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D012016:Reference Values; D014517:Ureteral Obstruction / Q000503:physiopathology*