title: Effects of endotoxin-induced shock on withdrawal contractions in the Guinea-pig isolated ileum.
abstract: 1. Taking into consideration the effect of septic shock on releasing various mediators, the present study was undertaken in an attempt to elucidate the effect of endotoxin on naloxone-induced withdrawal contractions in the guinea-pig isolated ileum. 2. To induce withdrawal contractions, preparations removed either from saline- or endotoxin (2.5 mg/kg in 0.4 mL, i.p.)-treated animals were incubated for 5 min with morphine (40 micromol/L) and naloxone (50 micromol/L) was then applied. 3. In tissues removed from endotoxin-treated animals, a significant reduction in withdrawal contractions was observed. In control preparations, indomethacin (1 micromol/L for 15 min) significantly reduced naloxone-induced contractions, whereas N(G)-nitro-L-arginine methyl ester (L-NAME; 10 micromol/L for 15 min) had no effect. However, indomethacin pretreatment of tissues removed from endotoxin-treated animals did not modify the withdrawal contractions, whereas L-NAME pretreatment enhanced the amplitude of the withdrawal-induced contractions. 4. These results suggest that attenuation of the withdrawal contractions in guinea-pig isolated ileum induced by endotoxin-pretreatment may be due, in part, to the activation of an L-arginine-nitric oxide pathway.
authors.affiliation: Department of Physiology and Pharmacology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: M
authors.initials: M
authors.lastname: Fatehi
authors.forename: A
authors.initials: A
authors.lastname: Tanomand
authors.forename: Z
authors.initials: Z
authors.lastname: Fatehi-Hassanabad
mesh_terms: D000818:Animals; D004731:Endotoxins / Q000633:toxicity*; D005260:Female; D006168:Guinea Pigs; D007082:Ileum / Q000187:drug effects; D066298:In Vitro Techniques; D007213:Indomethacin / Q000494:pharmacology; D008297:Male; D009020:Morphine / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects*; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009270:Naloxone / Q000494:pharmacology; D012772:Shock, Septic / Q000503:physiopathology*; D013375:Substance Withdrawal Syndrome / Q000503:physiopathology*
chemical_list: D004731:Endotoxins; D009270:Naloxone; D009020:Morphine; D019331:NG-Nitroarginine Methyl Ester; D007213:Indomethacin