title: ONO-1714, a new inducible nitric oxide synthase inhibitor, attenuates diaphragmatic dysfunction associated with cerulein-induced pancreatitis in rats.
abstract: OBJECTIVE
  Acute experimental pancreatitis (induced by cerulein) recently has been reported to cause marked diaphragmatic dysfunction, which may contribute to respiratory distress in this setting. In cerulein-induced acute pancreatitis, expression of inducible nitric oxide synthase is induced to produce a large amount of nitric oxide. Nitric oxide excessively produced has been implicated in diaphragmatic dysfunction induced by a variety of etiologies. The aims of the current study were, first, to examine whether nitric oxide overproduced through inducible nitric oxide synthase is involved in cerulein-induced impairment of diaphragmatic function, and second, if demonstrated, to assess effects of ONO-1714, an inducible nitric oxide synthase inhibitor, on diaphragmatic dysfunction associated with cerulein-induced acute pancreatitis.
  
  
  METHODS
  Prospective, randomized animal study.
  
  
  METHODS
  University research laboratory.
  
  
  METHODS
  Ninety-one male Sprague-Dawley rats, weighing 200-250 g.
  
  
  METHODS
  Rats were randomly divided into seven groups (n = 8 each): CONT-SAL, CAER-SAL, CONT-ONO, CAER-DEX, CAER-AMI, CAER-ONOhigh, and CAER-ONOlow. Groups labeled CAER received two consecutive intraperitoneal doses (50 microg/kg) of cerulein, whereas groups labeled CONT received two consecutive intraperitoneal injections of saline. Groups labeled SAL received intraperitoneal saline before cerulein or saline. The group labeled DEX received 2 mg/kg intraperitoneal dexamethasone, and the group labeled AMI received 100 mg/kg intraperitoneal aminoguanidine. The groups labeled ONO, ONOhigh, and ONOlow received ONO-1714 at 0.1 mg/kg, 0.1 mg/kg, and 0.03 mg/kg, respectively, before cerulein or saline.
  
  
  RESULTS
  Diaphragmatic contractility and fatigability were assessed in vitro by using muscle strips excised from the costal diaphragms 6 hrs after the first dose of cerulein or saline. Expression of inducible nitric oxide synthase protein in the diaphragm was assessed by immunohistochemistry by using anti-inducible nitric oxide synthase antibody. Plasma concentrations of nitrite plus nitrate and diaphragmatic concentrations of malondialdehyde were measured. With another set of rats (n = 5 each group), diaphragmatic inducible nitric oxide synthase activity was determined. Twitch and tetanic tensions and tensions generated during fatigue trial were lower in group CAER-SAL than in group CONT-SAL. Cerulein increased diaphragmatic malondialdehyde and plasma nitrite plus nitrate concentrations. Positive immunostaining for inducible nitric oxide synthase protein was found in group CAER-SAL. Dexamethasone and aminoguanidine attenuated the diaphragmatic mechanical damages. A high dose of ONO-1714 attenuated cerulein-induced impairment of diaphragmatic contractility and endurance capacity, although a low dose of the drug failed to do so.
  
  
  CONCLUSIONS
  Cerulein-induced diaphragmatic dysfunction was attributable, in part, to nitric oxide overproduced via inducible nitric oxide synthase. Pretreatment with ONO-1714 at a dose of 0.1 mg/kg attenuated diaphragmatic dysfunction associated with cerulein-induced pancreatitis in rats assessed by contractile profiles and endurance capacity. This beneficial effect of ONO-1714 may be attributable, in part, to inhibition of diaphragmatic lipid peroxidation induced by nitric oxide-derived free radicals.
authors.affiliation: Departments of Anaesthesiology and Intensive Care Unit, Kobe University School of Medicine, Kusunoki-cho 7, Chuo-ku, Kobe 650-0017, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Mikawa
authors.forename: S I
authors.initials: SI
authors.lastname: Kodama
authors.forename: K
authors.initials: K
authors.lastname: Nishina
authors.forename: H
authors.initials: H
authors.lastname: Obara
mesh_terms: D000578:Amidines / Q000494:pharmacology*; D000704:Analysis of Variance; D000818:Animals; D002108:Ceruletide; D003964:Diaphragm / Q000378:metabolism / Q000503:physiopathology*; D004195:Disease Models, Animal; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006574:Heterocyclic Compounds, 2-Ring / Q000494:pharmacology*; D007150:Immunohistochemistry; D015227:Lipid Peroxidation; D008297:Male; D008315:Malondialdehyde / Q000378:metabolism; D009119:Muscle Contraction / Q000502:physiology; D009569:Nitric Oxide / Q000097:blood; D010195:Pancreatitis / Q000188:drug therapy* / Q000503:physiopathology*; D011446:Prospective Studies; D051381:Rats; D017207:Rats, Sprague-Dawley; D012120:Respiration Disorders / Q000188:drug therapy* / Q000209:etiology / Q000503:physiopathology; D018709:Statistics, Nonparametric
chemical_list: C407360:7-chloro-3-imino-5-methyl-2-azabicyclo(4.1.0)heptane; D000578:Amidines; D004791:Enzyme Inhibitors; D006574:Heterocyclic Compounds, 2-Ring; D009569:Nitric Oxide; D008315:Malondialdehyde; D002108:Ceruletide