title: The hepatorenal reflex contributes to the induction of oliguria during pneumoperitoneum in the rat.
abstract: BACKGROUND
  Hepatic blood flow is known to decrease during pneumoperitoneum. Studies have shown that such changes affect kidney urinary output through the sympathetic pathway known as the hepatorenal reflex. This study investigated the potential role of the hepatorenal reflex in pneumoperitoneum-induced oliguria. The authors hypothesized that oliguria detectable during pneumoperitoneum is caused by activation of the hepatorenal reflex.
  
  
  METHODS
  Denervation of the sympathetic nervous structure was performed in 15 rats by applying 1 ml of 90 % aqueous phenol solution circumferentially to the portal vein and vena cava area at their entrance to the liver. The same was applied to only the peritoneum in 15 nondenervated rats. After 2 weeks, the rats were divided into three subgroups (5 rats per subgroup) that were exposed respectively to carbon dioxide-induced pneumoperitoneum at 0, 10, and 15 mmHg for 2 h. Statistical analysis was performed using Student's t test and analyses of variance.
  
  
  RESULTS
  Denervation did not affect the preinsufflation parameters. The denervated and the nondenervated 0-mmHg subgroups presented with similar parameters. The postinsufflation mean urine output was significantly lower in the nondenervated than in the denervated 10- and 15-mmHg subgroups (p = 0.0097). The denervated rats had a final creatinine clearance 29 % lower than the preinsufflation value (p = 0.83), whereas the nondenervated animals presented a 79 % drop in creatinine clearance (p = 0.02).
  
  
  CONCLUSIONS
  The study findings indicate that the hepatorenal reflex plays an important role in the pathophysiology of oliguria that occurs during pneumoperitoneum in the rat.
authors.affiliation: Department of Pediatric Surgery, Edith Wolfson Medical Center, Holon, Sackler Faculty of Medicine, Tel Aviv, Israel.
authors.forename: Gideon
authors.initials: G
authors.lastname: Karplus
authors.forename: Amir
authors.initials: A
authors.lastname: Szold
authors.forename: Francis
authors.initials: F
authors.lastname: Serour
authors.forename: Avi A
authors.initials: AA
authors.lastname: Weinbroum
mesh_terms: D000818:Animals; D007668:Kidney / Q000294:innervation*; D008099:Liver / Q000294:innervation*; D008297:Male; D009846:Oliguria / Q000209:etiology*; D011028:Pneumoperitoneum, Artificial / Q000009:adverse effects*; D051381:Rats; D017208:Rats, Wistar; D012018:Reflex