Effects of nitric oxide donor and nitric oxide synthase inhibitor on the resistance, exchange and capacitance functions of the canine intestinal vasculature.
In the present study, we determined the vascular functions using a canine model of isolated intestinal segment perfused with constant flow. The effects of an NO donor, S-nitroso-N-acetylpenicillamine (SNAP) and an NO synthase inhibitor, N(omega)-nitro-l-arginine methyl ester (l-NAME) on the vascular factors (resistance, exchange and capacitance) were evaluated. In condition of venous pressure at 0 mmHg, we determined and calculated arterial pressure (Pa) and capillary pressure (Pc). Vascular factors including total, pre- and post-capillary resistance (R(T), Ra and Rv), vascular compliance (VC) and capillary filtration coefficient (K(fc)) were obtained. SNAP at doses 10(-6) to 10(-4) mol/l produced vasodilatory effects. It dose-dependently reduced the Pa, Pc, R(T) and Ra, as well as the Ra/Rv ratio. The Rv was slightly decreased. This agent increased the vascular capacity, VC and K(fc). NO inhibition with l-NAME (10(-6) to 10(-4) mol/l) produced the opposite effects. The vasoconstrictory effects of l-NAME increased Pa, Pc, R(T) and Ra as well as the Ra/Rv ratio. It slightly raised the Rv. l-NAME reduced the vascular capacity, VC and K(fc). The effects of l-NAME were also dose-dependent. This study has provided a detailed data of the vasodilatory and vasoconstrictory effects NO donation and inhibition on vascular factors in the intestinal vasculature.
Hsieh
Nan-Kuang
NK
Department of Family Medicine, Tao-Yuan General Hospital, Taoyuan, Taiwan.
Chang
Huai-Ren
HR
Hu
Cheng-Tao
CT
Chen
Hsing I
HI
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002196:Capillaries / Q000187:drug effects / Q000201:enzymology; D002199:Capillary Permeability / Q000187:drug effects*; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D025802:Electric Capacitance; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D007082:Ileum / Q000098:blood supply*; D066298:In Vitro Techniques; D008638:Mesenteric Arteries / Q000187:drug effects / Q000201:enzymology; D008642:Mesenteric Veins / Q000187:drug effects / Q000201:enzymology; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism; D020030:Nitric Oxide Donors / Q000494:pharmacology*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors* / Q000378:metabolism; D010477:Perfusion; D026423:S-Nitroso-N-Acetylpenicillamine / Q000494:pharmacology; D013997:Time Factors; D014655:Vascular Resistance / Q000187:drug effects*; D014661:Vasoconstriction / Q000187:drug effects; D014662:Vasoconstrictor Agents / Q000494:pharmacology*; D014664:Vasodilation / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology*; D014690:Venous Pressure / Q000187:drug effects
D004791:Enzyme Inhibitors; D020030:Nitric Oxide Donors; D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D009569:Nitric Oxide; D026423:S-Nitroso-N-Acetylpenicillamine; D019001:Nitric Oxide Synthase; D019331:NG-Nitroarginine Methyl Ester