title: Flow-induced endothelium-dependent vasoreactivity in rat mesenteric arterial bed.
abstract: We studied rat mesenteric arterial beds to determine the relationship between the effects of flow-induced shear stress and agonists on mesenteric vasoreactivity. When beds were perfused at gradually increasing flow rates, perfusion pressure was flow rate-dependently increased. The flow rate-mediated increase in perfusion pressure was significantly enhanced by N(G)-nitro-L-arginine (L-NOARG) plus methylene blue (MB) and slightly enhanced by treatment with tetraethylammonium (TEA). In the presence of L-NOARG, MB, TEA, and indomethacin, the flow rate-induced increase in perfusion pressure was significantly enhanced, but this enhancement was significantly inhibited by combined treatment with BQ-123 plus BQ-788 (ET(A)- and ET(B)- receptor antagonists, respectively). The ET-1 content of the perfusate was significantly increased following combined pretreatment with L-NOARG, MB, TEA, and indomethacin at a high flow rate. The methoxamine-induced contraction was significantly enhanced by NOS inhibition in both high- and low- flow-treated groups. The released nitrite level was significantly greater in high-flow-loaded than in the low-flow-loaded beds. We conclude that in this model, the response of vascular tone to flow stimulation is subtly regulated by endothelium-derived factors (especially, NO, endothelium-derived hyperpolarizing factor, and ET-1), and that these factors interact with each other.
authors.affiliation: Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Tokyo, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Matsumoto
authors.forename: Shu-ich
authors.initials: SI
authors.lastname: Oda
authors.forename: Tsuneo
authors.initials: T
authors.lastname: Kobayashi
authors.forename: Katsuo
authors.initials: K
authors.lastname: Kamata
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000502:physiology; D002317:Cardiovascular Agents / Q000494:pharmacology; D019332:Endothelin-1 / Q000378:metabolism; D004730:Endothelium, Vascular / Q000502:physiology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007213:Indomethacin / Q000494:pharmacology; D008297:Male; D008638:Mesenteric Arteries / Q000502:physiology*; D008751:Methylene Blue / Q000494:pharmacology; D009566:Nitrates / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism; D019335:Nitroarginine / Q000494:pharmacology; D010477:Perfusion; D026902:Potassium Channel Blockers / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D012039:Regional Blood Flow / Q000187:drug effects / Q000502:physiology*; D013314:Stress, Mechanical; D019789:Tetraethylammonium / Q000494:pharmacology; D014661:Vasoconstriction / Q000187:drug effects / Q000502:physiology
chemical_list: D002317:Cardiovascular Agents; D019332:Endothelin-1; D004791:Enzyme Inhibitors; D009566:Nitrates; D009573:Nitrites; D026902:Potassium Channel Blockers; D019335:Nitroarginine; D019789:Tetraethylammonium; D008751:Methylene Blue; D007213:Indomethacin