title: Nitric oxide and endothelium-dependent relaxation in tracheobronchial lymph vessels.
abstract: Lymphatic smooth muscle tone and contractility are important determinants of lymph flow. Because we have shown previously that lymph vessels exhibit endothelium-dependent relaxation similar to that identified in blood vessels, we assessed the possible role of nitric oxide as an endothelium-dependent relaxant factor in lymph vessels using porcine tracheobronchial lymph vessel rings mounted in organ baths. Isometric active tension was measured and normalized as a percentage of response to 65 mM KCl-substituted perfusate. Histamine and NE elicited contraction in all vessel rings at a concentration of 10(-5) M, and we were unable to demonstrate relaxant responses to these substances even at low concentrations. In histamine- and NE-contracted vessel rings an increase in active tension was produced by NMMA (33.9 +/- 5.4 and 26.1 +/- 5%, respectively, P < 0.0001 for each), an effect that was reversed by addition of L-arginine but not by D-arginine. Endothelial disruption reversed the effects of NMMA in histamine-contracted (16.2 +/- 4.0% increase in active tension; P = N.S. vs initial histamine response) and in NE-contracted vessel rings (11.5 +/- 1.2% increase in active tension; P = N.S. vs initial NE response). The data provide evidence that nitric oxide is an endothelium-dependent relaxant factor that regulates tracheobronchial lymphatic smooth muscle tone and is released in response to administration of contractile agonists.
authors.affiliation: Department of Surgery, University of Chicago, Illinois 60637.
authors.forename: M K
authors.initials: MK
authors.lastname: Ferguson
authors.forename: V J
authors.initials: VJ
authors.lastname: DeFilippi
mesh_terms: D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D001980:Bronchi / Q000187:drug effects / Q000502:physiology; D004729:Endothelium, Lymphatic / Q000187:drug effects / Q000502:physiology*; D005260:Female; D006632:Histamine / Q000494:pharmacology; D066298:In Vitro Techniques; D008208:Lymphatic System / Q000187:drug effects / Q000502:physiology*; D008297:Male; D009126:Muscle Relaxation / Q000187:drug effects / Q000502:physiology; D009569:Nitric Oxide / Q000037:antagonists & inhibitors / Q000502:physiology*; D009638:Norepinephrine / Q000494:pharmacology; D010477:Perfusion; D014132:Trachea / Q000187:drug effects / Q000502:physiology; D019323:omega-N-Methylarginine
chemical_list: D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D006632:Histamine; D001120:Arginine; D009638:Norepinephrine