TY - JOUR T1 - Suppression of Acute Experimental Colitis by a Highly Selective Inducible Nitric-Oxide Synthase Inhibitor,<em>N</em>-[3-(Aminomethyl)benzyl]acetamidine JF - Journal of Pharmacology and Experimental Therapeutics JO - J Pharmacol Exp Ther SP - 1128 LP - 1132 VL - 298 IS - 3 AU - Esko Kankuri AU - Kirsi Vaali AU - Richard G. Knowles AU - Mari Lähde AU - Riitta Korpela AU - Heikki Vapaatalo AU - Eeva Moilanen Y1 - 2001/09/01 UR - http://jpet.aspetjournals.org/content/298/3/1128.abstract N2 - High concentrations of nitric oxide (NO) produced by the inducible nitric-oxide synthase (iNOS) are associated with ulcerative inflammation and disease activity in colitis. Therefore, inhibition of iNOS serves as a novel experimental approach to treat gut inflammation. The aim of the present study was to investigate the effects of a novel highly selective iNOS inhibitor,N-[3-(aminomethyl)benzyl]acetamidine (1400W), as compared with a nonselective NOS inhibitor,N(G)-nitro-l-arginine-methyl-ester (l-NAME), in 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced acute colitis in the rat. Increased expression of iNOS protein and mRNA was found in acute TNBS-induced colitis along with neutrophil infiltration, inflammatory edema, and tissue damage. In a 24-h model of acute colitis, subcutaneous injections of 1400W (5 or 10 mg/kg t.i.d.) produced a 56 and 95% reduction in inflammatory edema formation, a 68 and 63% reduction in neutrophil infiltration (measured as myeloperoxidase activity), and a 19 and 26% decrease in the size of mucosal lesions as compared with vehicle treatment. Administration ofl-NAME (35 mg/kg) failed to produce any significant beneficial effects as compared with vehicle treatment in this experimental model of acute colitis. Treatment with 1400W, a highly selective inhibitor of iNOS, reduced formation of edema, neutrophil infiltration, and macroscopic inflammatory damage in experimentally induced acute colitis in the rat. In contrast, nonselective nitric-oxide synthase inhibition with l-NAME provided no benefit. These results support the idea that selective iNOS inhibitors have a promise in the treatment of colitis. The American Society for Pharmacology and Experimental Therapeutics ER -