Decreased endothelium dependent relaxation (nitric oxide) in diabetic kidneys.
To evaluate the endothelium-dependent vasodilatation in diabetic kidneys, we have perfused rabbit kidneys at 30 degrees C with Krebs-Henseleit solution in a non-recirculated perfusion system. To increase vascular tonus, we infused norepinephrine (NOR) (10(-6)M) into the renal artery. After the vasoconstriction reached steady state conditions, a dose-response study was performed with acetylcholine (Ach) and bradykinin (Bk). Administration of Ach (10(-7)M - 10(-5)M) or Bk (10(-8) - 10(-7)M) in cumulative curves through the renal artery promoted a vasodilation, which was dose-dependent in normal and diabetic (three weeks after 150 mg of alloxan, intraperitoneally) kidney. We found a decreased vasodilator response to Ach (p < 0.05) and Bk (p < 0.01) in diabetic animals, when compared to controls. When sodium nitroprusside (10(-8) - 10(-7)M) was administrated through the renal artery to evaluate the endothelium-independent vasodilating effects, a similar vasodilator response was found in both normal and diabetic kidneys. These data indicate for a failure of the vasodilator mechanism dependent on endothelium in alloxan-diabetic kidneys.
Costa e Forti
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Department of Clinical Medicine, Federal University of Cearä, Fortaleza.
Fonteles
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D000109:Acetylcholine / Q000494:pharmacology; D000496:Alloxan / Q000494:pharmacology; D000818:Animals; D001920:Bradykinin / Q000494:pharmacology; D003921:Diabetes Mellitus, Experimental / Q000503:physiopathology*; D004730:Endothelium, Vascular / Q000187:drug effects*; D005260:Female; D007668:Kidney / Q000502:physiology; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects; D009569:Nitric Oxide / Q000502:physiology; D009599:Nitroprusside / Q000494:pharmacology; D009638:Norepinephrine / Q000494:pharmacology; D011817:Rabbits; D014661:Vasoconstriction / Q000187:drug effects; D014664:Vasodilation / Q000187:drug effects*
D009599:Nitroprusside; D009569:Nitric Oxide; D000496:Alloxan; D000109:Acetylcholine; D001920:Bradykinin; D009638:Norepinephrine