title: Relationship between nitric oxide and platelet-activating factor in castor-oil induced mucosal injury in the rat duodenum.
abstract: The modulation of platelet activating factor (PAF) formation in duodenal tissue by nitric oxide (NO) released in response to castor oil was studied in rats pretreated with NG-nitro-L-arginine methyl ester (L-NAME, 6.25-25 mg/kg, i.p.), an inhibitor of NO synthase, NG-nitro-D-arginine methyl ester (D-NAME, 25 mg/kg, i.p.), the inactive enantiomer of L-NAME or isosorbide-5-mononitrate (IMN, 30-90 mg/kg, p.o.), a NO donating compound. Castor oil (2 ml/rat orally) increased PAF production in the rat duodenum 3 h after challenge. L-NAME, but not D-NAME, enhanced the amount of PAF formed by duodenal tissue, while IMN (30-90 mg/kg) counteracted the effects of L-NAME (12.5 mg/kg) and also reduced PAF release in the tissue of rats treated with castor oil. L-NAME 12.5 mg/kg, but not D-NAME, enhanced both macroscopic damage and acid phosphatase release induced by castor oil. These effects were reduced by a PAF antagonist BN 52021 (3-t-Butyl-hexahydro-4, 7b, 11-trihydroxy-8-methyl-9H-1, 7a-epoxymethano-1H, 6aH-cyclopenta [c] furo [2, 3b] furo [3'2':3,4] cyclopenta [1.2-d]furan-5,9,12(4H)trione) 10 and 20 mg/kg i.p. Such findings suggest that endogenous nitric oxide could reduce PAF biosynthesis in castor oil-treated rats.
authors: Department of Experimental Pharmacology, School of Pharmacy, Naples, Italy.
authors: N
authors: N
authors: Mascolo
authors: A A
authors: AA
authors: Izzo
authors: T S
authors: TS
authors: Gaginella
authors: F
authors: F
authors: Capasso
mesh_terms: D000135:Acid Phosphatase / Q000378:metabolism; D000818:Animals; D002368:Castor Oil / Q000009:adverse effects / Q000494:pharmacology*; D002400:Cathartics / Q000494:pharmacology*; D004234:Diuretics, Osmotic / Q000494:pharmacology; D004386:Duodenum / Q000187:drug effects* / Q000378:metabolism; D007547:Isosorbide / Q000494:pharmacology; D008297:Male; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000502:physiology*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000494:pharmacology; D010972:Platelet Activating Factor / Q000096:biosynthesis*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D002400:Cathartics; D004234:Diuretics, Osmotic; D010972:Platelet Activating Factor; D009569:Nitric Oxide; D002368:Castor Oil; D019001:Nitric Oxide Synthase; D000135:Acid Phosphatase; D019331:NG-Nitroarginine Methyl Ester; D007547:Isosorbide