Time-dependent alterations in serum NO concentration after oral administration of L-arginine, L-NAME, and allopurinol in intestinal ischemia/reperfusion

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Authors: Amalia E Yanni, Eleutherios Margaritis, Nikolaos Liarakos, Alkisti Pantopoulou, Maria Poulakou, et al

Published Date May 2008 Volume 2008:4(2) Pages 437 - 441

DOI: http://dx.doi.org/10.2147/VHRM.S2433

Amalia E Yanni¹, Eleutherios Margaritis², Nikolaos Liarakos², Alkisti Pantopoulou², Maria Poulakou², Maria Kostakis², Despoina Perrea², Alkis Kostakis³

¹Department of Science of Dietetics and Nutrition, Harokopio University of Athens, Athens, Greece, ²Laboratory of Experimental Surgery and Surgical Research, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece, ³2nd Department of Propedeutic Surgery, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece

Objective: To study the effect of oral administration of a nitric oxide (NO) donor L-arginine (L-Arg), a NO synthase inhibitor N^G-nitro-L-arginine methyl ester (L-NAME) and an inhibitor of xanthine oxidase, allopurinol (Allo), on serum NO concentration and catalase activity after intestinal ischemia/reperfusion (I/R) in rats.

Methods: Male Wistar rats received per os L-Arg (800 mg/kg) or L-NAME (50 mg/kg) or Allo (100 mg/kg) 24 hrs, 12 hrs and 1 hr before underwent 1 hr occlusion of superior mesenteric artery followed by 1 hr of reperfusion (L-Arg(IR1), L-NAME(IR1) and Allo(IR1) respectively) or 1 hr occlusion followed by 8 hrs of reperfusion (L-Arg(IR8), L-NAME(IR8) and Allo(IR8) respectively). There was one group underwent 1 hr occlusion (I), a group underwent 1 hr occlusion followed by 1 hr reperfusion (IR1), a group subjected to 1 hr occlusion followed by 8 hrs of reperfusion (IR8) and a last group that served as control (C). Serum NO concentration and catalase activity were measured.

Results: After 1 hr of reperfusion serum NO concentration was elevated in IR1 and L-Arg(IR1) groups compared with group C but not in L-NAME(IR1) and Allo(IR1) group. Catalase activity was enhanced in L-NAME(IR1) group. Interestingly, serum NO concentration was increased after 8 hrs of reperfusion in all groups (IR8, L-Arg(IR8), L-NAME(IR8) and Allo(IR8)) compared with control while catalase activity did not show significant difference in any group.

Conclusions: The results of the present study show that NO concentration is elevated in serum after intestinal I/R and the elevation sustained after administration of L-Arg but not after administration of L-NAME or Allo after 1 hr reperfusion. However, after 8 hrs of reperfusion NO concentration was increased in all groups studied, focusing attention on its possible important role in a complicated situation such as intestinal I/R that involves intestine and other organs. Serum catalase activity does not seem to be affected by per os supplementation of L-Arg or Allo in intestinal I/R.

Keywords: intestine, ischemia-reperfusion, nitric oxide, L-Arginine, N^G-nitro-L-arginine methyl ester, allopurinol

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