Original article
English
Wisam Elbishti
Department of Pharmacology, Faculty of Medicine, Al-Fateh University of Medical Sciences, Tripoli, Libya
JMJ Vol.8, No.1 (Spring) 2008:26-30
Abstract
Recent research has indicated that nitric oxide (NO) has gastric mucosal protective effects similar to those of prostaglandins (PGs), and that NO and PGs may act synergistically to maintain gastric mucosal integrity. Therefore, the present study aimed at evaluating the anti-ulcer activity of NO and its possible mechanism(s) of action. This was established by investigating the effects of orally administered single and repeated doses of the NO donor sodium nitroprusside ( SNP, 3 mg / Kg ) or the NO precursor L-arginine ( 200 mg / Kg ) on cold restraint stress-induced and aspirin-induced gastric ulcer in rats, as well as on total gastric acidity in pyloric-ligated rats subjected to stress ulcer. The effects of the H2-receptor antagonist ranitidine also were investigated for comparison. Single and repeated doses of SNP caused a significant decrease in the number ( 56 % and 64 %, respectively ) and length ( 51 % and 48 %, respectively ) of gastric lesions in stress-induced ulcer. The protective effect of SNP against ulcer formation was even more marked on aspirin-induced ulcer, causing 71 % and 92 % decrease in the number, and 62 % and 82 % decrease in the length of gastric lesions, respectively. Single and repeated doses of L-arginine also were effective in reducing the number and length of gastric lesions in both ulcer models, but to a lesser extent than with SNP. In pyloric-ligated rats, single and repeated doses of SNP or L-arginine caused only moderate reductions in total gastric acidity ( 27 % and 31 % for SNP ; 20 % and 25 % for L-arginine, respectively ). Single and repeated doses of ranitidine also produced a significant decrease in the number and length of gastric lesions in both ulcer models, and in total gastric acidity in pyloric-ligated rats. The order of anti-ulcer activity of the three drugs was as follows : Stress-induced ulcer : ranitidine > SNP > L-arginine. Aspirin-induced ulcer : SNP > L-arginine > ranitidine. These results show that NO exerts a significant protective effect against both stress-induced and aspirin-induced ulcer. Inhibition of gastric acid secretion may contribute but is not the only mechanism of the anti-ulcer activity of NO. The results also suggest that concurrent administration of NO donors or L-arginine may be beneficial in prophylaxis against non-steroidal anti-inflammatory drugs ( NSAIDs )- induced gastric ulcer.
Keywords: Nitric oxide, Stress and aspirin-induced gastric ulcer
Link/DOI: http://www.jmj.org.ly/modules.php?name=News&file=article&sid=1447