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1.
Braz. j. med. biol. res ; 36(9): 1175-1178, Sept. 2003. tab, graf
Article in English | LILACS | ID: lil-342859

ABSTRACT

Mechanical forces including pressure and shear stress play an important role in vascular homeostasis via the control of the production and release of a variety of vasoactive factors. An increase in vascular shear stress is accompanied by nitric oxide (NO) release and NO synthase activation. Previously, we have demonstrated that shear stress induces angiotensin-I converting enzyme (ACE) down-regulation in vivo and in vitro. In the present study, we determined whether NO participates in the shear stress-induced ACE suppression response. Rabbit aortic endothelial cells were evaluated using the NO synthase inhibitor L-NAME, and two NO donors, diethylamine NONOate (DEA/NO) and sodium nitroprusside (SNP). Under static conditions, incubation of endothelial cells with 1 mM L-NAME for 18 h increased ACE activity by 27 percent (from 1.000 ± 0.090 to 1.272 ± 0.182) while DEA/NO and SNP (0.1, 0.5 and 1 mM) caused no change in ACE activity. Interestingly, ACE activity was down-regulated similarly in the presence or absence of L-NAME (delta(0 mM) = 0.26 ± 0.055, delta(0.1 mM) = 0.21 ± 0.22, delta(1 mM) = 0.36 ± 0.13) upon 18 h shear stress activation (from static to 15 dyn/cm²). Taken together, these results indicate that NO can participate in the maintenance of basal ACE levels in the static condition but NO is not associated with the shear stress-induced inactivation of ACE


Subject(s)
Animals , Rabbits , Hemorheology , Nitric Oxide , Nitric Oxide Synthase , Peptidyl-Dipeptidase A , Aorta , Endothelium, Vascular , Enzyme Activation , Enzyme Inhibitors , Hydrazines , Luciferases , NG-Nitroarginine Methyl Ester , Nitric Oxide Donors , Nitric Oxide Synthase , Nitroprusside , Peptidyl-Dipeptidase A , Time Factors
2.
Braz J Med Biol Res ; 36(9): 1175-8, 2003 Sep.
Article in English | MEDLINE | ID: mdl-12937782

ABSTRACT

Mechanical forces including pressure and shear stress play an important role in vascular homeostasis via the control of the production and release of a variety of vasoactive factors. An increase in vascular shear stress is accompanied by nitric oxide (NO) release and NO synthase activation. Previously, we have demonstrated that shear stress induces angiotensin-I converting enzyme (ACE) down-regulation in vivo and in vitro. In the present study, we determined whether NO participates in the shear stress-induced ACE suppression response. Rabbit aortic endothelial cells were evaluated using the NO synthase inhibitor L-NAME, and two NO donors, diethylamine NONOate (DEA/NO) and sodium nitroprusside (SNP). Under static conditions, incubation of endothelial cells with 1 mM L-NAME for 18 h increased ACE activity by 27% (from 1.000 +/- 0.090 to 1.272 +/- 0.182) while DEA/NO and SNP (0.1, 0.5 and 1 mM) caused no change in ACE activity. Interestingly, ACE activity was down-regulated similarly in the presence or absence of L-NAME (delta(0 mM) = 0.26 0.055, delta(0.1 mM) = 0.21 +/- 0.22, delta(1 mM) = 0.36 +/- 0.13) upon 18 h shear stress activation (from static to 15 dyn/cm2 ). Taken together, these results indicate that NO can participate in the maintenance of basal ACE levels in the static condition but NO is not associated with the shear stress-induced inactivation of ACE.


Subject(s)
Hemorheology , Nitric Oxide Synthase/metabolism , Nitric Oxide/physiology , Peptidyl-Dipeptidase A/metabolism , Animals , Aorta/cytology , Cells, Cultured , Down-Regulation , Endothelium, Vascular/enzymology , Enzyme Activation , Enzyme Inhibitors/pharmacology , Hydrazines/pharmacology , Luciferases/drug effects , Luciferases/metabolism , NG-Nitroarginine Methyl Ester/pharmacology , Nitric Oxide Donors/pharmacology , Nitric Oxide Synthase/drug effects , Nitrogen Oxides , Nitroprusside/pharmacology , Peptidyl-Dipeptidase A/drug effects , Rabbits , Time Factors
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