Nitric oxide modulates epithelial permeability in the feline small intestine
Kubes, P.
American Journal of Physiology 262(6 Pt 1): G1138-G1142
1992
ISSN/ISBN: 0002-9513 PMID: 1616043 Document Number: 391477
The objective of this study was to assess whether inhibition of nitric oxide production leads to increased epithelial permeability in feline small intestine. Local intra-arterial infusion of the nitric oxide synthesis inhibitor NG-nitro-L-arginine-methyl ester (L-NAME; 0.025 .mu.mol .cntdot. ml-1 < min-1) was performed in autoperfused segments of cat ileum for 90 min. An exogenous source of nitric oxide, sodium nitroprusside (SNP) was infused. (0.025 .mu.mol .cntdot. ml-1 .cntdot. min-1)for the last 30 min of the 90-min L-NAME infusion. Epithelial permeability was quantitated by measuring blood-to-lumen clearance of 51Cr-labeled EDTA throughout the experiment. An increase of approximately sixfold in mucosal permeability was observed within 30 min of L-NAME infusion and this effect was completely reversed by infusion of either SNP or L-arginine (0.125 .mu.mol .cntdot. ml-1 .cntdot. min-1). NG-nitro-D-arginine-methyl ester (D-NAME) had no effect on mucosal permeability. The increases in epithelial permeability was sufficiently large that rhodamine-dextran (mol wt = 17,200) clearance from interstitium to lumen was increased. Pretreatment with IB4, a monoclonal antibody directed against the leukocyte adhesive glycoprotein complex (CD11/CD18) did not prevent the L-NAME-induced increase in epithelial permeability. These data suggest that inhibiton of nitric oxide production leads to a reversible circulating leukocyte-independent increases in epithelial permeability.