Helicobacter pylori lipopolysaccharide-provoked injury to rat gastroduodenal microvasculature involves inducible nitric oxide synthase

The actions of a purified Helicobacter pylori lipopolysaccharide (3 mg kg(- 1), i.v.) on rat gastric antral and duodenal microvascular integrity (deter mined as radiolabelled albumin leakage) and the expression of the inducible nitric oxide (NO) synthase (iNOS; assessed by the citrulline assay) were i nvestigated 4 h after challenge. Significant increases of albumin leakage a nd expression of iNOS in both antral and duodenal tissues were observed fol lowing challenge. Concurrent administration of the selective iNOS inhibitor , 1400W (N-(8-(aminomethyl)benzyl)-acetamidine: 0.2-1 mg kg (-1), s.c.), wi th lipopolysaccharide, caused a dose-dependent attenuation of the gastric a nd duodenal albumin leakage. Thus, H. pylori lipopolysaccharide can initiat e the expression of iNOS in the stomach and duodenum following systemic cha llenge, which can provoke gastroduodenal microvascular dysfunction. (C) 200 1 Elsevier Science B.V. All rights reserved.