title: Norepinephrine inhibits the pelvic pressure increase in response to flow perfusion.
abstract: OBJECTIVE
  We evaluated the effects of norepinephrine on transport pressures in the normal upper urinary tract of the pig during increasing perfusion rates.
  
  
  METHODS
  Anesthetized Danish landrace Yorkshire pigs weighing 38 to 40 kg were studied. Transparenchymally 2, 6Fr catheters were introduced into the left renal pelvis for pressure measurements and perfusion, respectively. An ultrasonic flow probe was inserted around the left renal artery to record blood flow. A 10Fr catheter was placed transurethrally for bladder drainage and the bladder was maintained empty during the entire study. In the 5 group 1 pigs the pelvic pressure increase was examined at increasing perfusion rates of the renal pelvis (2, 4, 6, 8, 10 and 15 ml per minute) in response to endoluminal administration of increasing concentrations of norepinephrine (0, 5, 50 and 100 microg/ml) in saline. In the 5 group 2 pigs the pressure flow study was also done 4 times per animal using isotonic saline.
  
  
  RESULTS
  Endoluminal norepinephrine had a dose dependent effect on the pressure flow relationship. Perfusion with 5 and 50 microg/ml norepinephrine caused a delayed increase and a decrease in pelvic pressure in response to increasing flow rates, whereas perfusion with 100 microg/ml norepinephrine significantly inhibited and almost eliminated the pressure increase at all perfusion rates compared with saline perfusion. Importantly there were no changes in blood pressure, the heart rate or renal arterial blood flow. In group 2 perfusion with isotonic saline resulted in the same pressure response to increasing flow rates each time.
  
  
  CONCLUSIONS
  Endoluminal administration of norepinephrine caused a dose dependent inhibition on the pressure phases of the pressure flow relationship of the upper urinary tract in pigs. No systemic changes were observed. These observations may provide a useful adjuvant treatment strategy for upper urinary tract stone treatment and endoscopy.
authors.affiliation: Department of Surgery, Haderslev Sygehus, Haderslev, Denmark.
authors.forename: U
authors.initials: U
authors.lastname: Holst
authors.forename: T
authors.initials: T
authors.lastname: Dissing
authors.forename: Y F
authors.initials: YF
authors.lastname: Rawashdeh
authors.forename: J
authors.initials: J
authors.lastname: Frokiaer
authors.forename: J C
authors.initials: JC
authors.lastname: Djurhuus
authors.forename: J
authors.initials: J
authors.lastname: Mortensen
mesh_terms: D000316:Adrenergic alpha-Agonists / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D004305:Dose-Response Relationship, Drug; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D009638:Norepinephrine / Q000008:administration & dosage / Q000494:pharmacology*; D013552:Swine; D014551:Urinary Tract / Q000187:drug effects; D014563:Urodynamics / Q000187:drug effects*
chemical_list: D000316:Adrenergic alpha-Agonists; D009638:Norepinephrine