Multiple nitric oxide sources in neurogenic plasma extravasation in rat hindpaw skin.
The contribution of nitric oxide (NO) to capsaicin-evoked plasma extravasation was studied in rat hindpaw skin. Two inhibitors of NO synthase were used: 7-nitroindazole, with a selectivity for nerve-derived NO, and the L-arginine derivative, N(omega)-nitro-L-arginine (L-NOARG), which is a non-selective inhibitor. Plasma extravasation was induced by intraplantar injection of 5 microg/50 microl capsaicin and measured by the Evans blue leakage technique. Both acute and chronic administration of 7-nitroindazole significantly reduced capsaicin-evoked plasma extravasation in rat hind-paw skin, whereas L-NOARG enhanced it. This enhancement was abolished non-stereospecifically by either L- or D-arginine. Our results suggest that NO production from different sources yields a complex action in maintaining the endothelial integrity in neurogenic plasma extravasation.
Department of Physiology, Albert Szent-Györgyi Medical University, Szeged, Hungary. szikszay@phys.szote.u-szeged.hu
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D000818:Animals; D001120:Arginine / Q000494:pharmacology; D002199:Capillary Permeability / Q000187:drug effects; D002211:Capsaicin / Q000494:pharmacology; D004396:Coloring Agents / Q000493:pharmacokinetics; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005070:Evans Blue / Q000493:pharmacokinetics; D005119:Extravasation of Diagnostic and Therapeutic Materials / Q000097:blood*; D006614:Hindlimb; D007191:Indazoles / Q000494:pharmacology; D008297:Male; D009569:Nitric Oxide / Q000502:physiology*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D051381:Rats; D017208:Rats, Wistar; D012867:Skin / Q000098:blood supply* / Q000294:innervation
D004396:Coloring Agents; D004791:Enzyme Inhibitors; D007191:Indazoles; D009569:Nitric Oxide; D005070:Evans Blue; D001120:Arginine; D019001:Nitric Oxide Synthase; D002211:Capsaicin; C080122:7-nitroindazole