title: Endothelium-dependent responses in small human mesenteric arteries.
abstract: The aim of the present study was to investigate the endothelial function in human mesenteric arteries with specific reference to defining the role of endothelium-derived nitric oxide (EDNO) and the endothelium-derived hyperpolarizing factor (EDHF). Isolated segments of small human mesenteric arteries (225-450 microm inner diameter) were mounted in organ baths for recording isometric tension. In arteries precontracted with U46619 (thromboxane A(2) analogue, 10(-7) M), endothelium-dependent relaxations were induced in a concentration-dependent manner by substance P and histamine. In normal Krebs solution the relaxations to substance P (10(-9) M) and histamine (10(-7) M) were not significantly affected by preincubation with N(omega)-nitro-L-arginine (L-NNA, 10(-4) M) or indomethacin (10(-5) M). When the preparations were exposed to a solution containing 60 mM KCl, stable contractions were induced, but relaxations could still be induced by substance P and histamine. When the arteries were further preincubated with L-NNA, the relaxations were almost abolished. A combination of apamin (3 x 10(-7) M) and charybdotoxin (10(-9) M) almost abolished relaxations in normal Krebs solution. It is concluded that isolated human mesenteric arteries respond to substance P and histamine with relaxations that are endothelium-dependent. Synthesis of both EDNO and EDHF seem important for these relaxations, whereas prostaglandins seem to be of minor importance.
authors.affiliation: Department of Surgery L, University Hospital of Aarhus, Amtssygehuset, Aarhus C, Denmark. anders_tottrup@hotmail.com
authors.forename: A
authors.initials: A
authors.lastname: Tottrup
authors.forename: K
authors.initials: K
authors.lastname: Kraglund
mesh_terms: D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid / Q000494:pharmacology; D001685:Biological Factors / Q000378:metabolism*; D004730:Endothelium, Vascular; D045462:Endothelium-Dependent Relaxing Factors / Q000378:metabolism*; D006632:Histamine / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D008638:Mesenteric Arteries / Q000187:drug effects* / Q000502:physiology*; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000502:physiology*; D009569:Nitric Oxide / Q000378:metabolism*; D011188:Potassium / Q000378:metabolism; D015221:Potassium Channels / Q000187:drug effects / Q000502:physiology; D013152:Splanchnic Circulation / Q000187:drug effects / Q000502:physiology; D013373:Substance P / Q000494:pharmacology
chemical_list: D001685:Biological Factors; D045462:Endothelium-Dependent Relaxing Factors; D015221:Potassium Channels; C067410:endothelium-dependent hyperpolarization factor; D009569:Nitric Oxide; D013373:Substance P; D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; D006632:Histamine; D011188:Potassium