scholarly journals Effects of in vivo adventitial expression of recombinant endothelial nitric oxide synthase gene in cerebral arteries

1997 ◽  
Vol 94 (23) ◽  
pp. 12568-12573 ◽  
Author(s):  
A. F. Y. Chen ◽  
S.-W. Jiang ◽  
T. B. Crotty ◽  
M. Tsutsui ◽  
L. A. Smith ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Endothelial Nitric Oxide Synthase ◽  
Cerebral Arteries ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide

Increasing dihydrobiopterin causes dysfunction of endothelial nitric oxide synthase in rats in vivo

2011 ◽  
Vol 301 (3) ◽  
pp. H721-H729 ◽  
Author(s):  
Katsuhiko Noguchi ◽  
Naobumi Hamadate ◽  
Toshihiro Matsuzaki ◽  
Mayuko Sakanashi ◽  
Junko Nakasone ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Endothelial Nitric Oxide Synthase ◽  
Control Treatment ◽  
Enos Uncoupling ◽  
Nos Inhibitor ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide ◽  
First Time

An elevation of oxidized forms of tetrahydrobiopterin (BH4), especially dihydrobiopterin (BH2), has been reported in the setting of oxidative stress, such as arteriosclerotic/atherosclerotic disorders, where endothelial nitric oxide synthase (eNOS) is dysfunctional, but the role of BH2 in the regulation of eNOS activity in vivo remains to be evaluated. This study was designed to clarify whether increasing BH2 concentration causes endothelial dysfunction in rats. To increase vascular BH2 levels, the BH2 precursor sepiapterin (SEP) was intravenously given after the administration of the specific dihydrofolate reductase inhibitor methotrexate (MTX) to block intracellular conversion of BH2 to BH4. MTX/SEP treatment did not significantly affect aortic BH4 levels compared with control treatment. However, MTX/SEP treatment markedly augmented aortic BH2 levels (291.1 ± 29.2 vs. 33.4 ± 6.4 pmol/g, P < 0.01) in association with moderate hypertension. Treatment with MTX alone did not significantly alter blood pressure or BH4 levels but decreased the BH4-to-BH2 ratio. Treatment with MTX/SEP, but not with MTX alone, impaired ACh-induced vasodilator and depressor responses compared with the control treatment (both P < 0.05) and also aggravated ACh-induced endothelium-dependent relaxations ( P < 0.05) of isolated aortas without affecting sodium nitroprusside-induced endothelium-independent relaxations. Importantly, MTX/SEP treatment significantly enhanced aortic superoxide production, which was diminished by NOS inhibitor treatment, and the impaired ACh-induced relaxations were reversed with SOD ( P < 0.05), suggesting the involvement of eNOS uncoupling. These results indicate, for the first time, that increasing BH2 causes eNOS dysfunction in vivo even in the absence of BH4 deficiency, demonstrating a novel insight into the regulation of endothelial function.

scholarly journals The Key Role of Caveolin-1 in Estrogen-Mediated Regulation of Endothelial Nitric Oxide Synthase Function in Cerebral Arterioles In vivo

2001 ◽  
Vol 21 (8) ◽  
pp. 907-913 ◽  
Author(s):  
Hao-Liang Xu ◽  
Elena Galea ◽  
Roberto A. Santizo ◽  
Verna L. Baughman ◽  
Dale A. Pelligrino
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Functional Activity ◽  
Endothelial Nitric Oxide Synthase ◽  
Down Regulation ◽  
Caveolin 1 ◽  
Cerebral Arterioles ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide

The marked impairment in cerebrovascular endothelial nitric oxide synthase (eNOS) function that develops after ovariectomy may relate to the observation that the abundance of cerebral vascular eNOS and its endogenous inhibitor, caveolin-1, vary in opposite directions with chronic changes in estrogen status. The authors endeavored, therefore, to establish a link between these correlative findings by independently manipulating, in ovariectomized female rats, eNOS and caveolin-1 expression, while monitoring agonist (acetylcholine)-stimulated eNOS functional activity. In the current study, the authors showed that individually neither the up-regulation of eNOS (through simvastatin treatment), nor the down-regulation of caveolin-1 (through antisense oligonucleotide administration) is capable of restoring eNOS function in pial arterioles in vivo in these estrogen-depleted rats. Only when eNOS up-regulation and caveolin-1 down-regulation are combined is activity normalized. These results establish a mechanistic link between the estrogen-associated divergent changes in the abundance of caveolin-1 and eNOS protein and eNOS functional activity in cerebral arterioles.

scholarly journals Characterization of three inhibitors of endothelial nitric oxide synthase in vitro and in vivo

1990 ◽  
Vol 101 (3) ◽  
pp. 746-752 ◽  
Author(s):  
D.D. Rees ◽  
R.M.J. Palmer ◽  
R. Schulz ◽  
H.F. Hodson ◽  
S. Moncada
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Endothelial Nitric Oxide Synthase ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide

scholarly journals Can endothelial hemoglobin-α regulate nitric oxide vasodilatory signaling?

2017 ◽  
Vol 312 (4) ◽  
pp. H854-H866 ◽  
Author(s):  
Jaimit Parikh ◽  
Adam Kapela ◽  
Nikolaos M. Tsoukias
Keyword(s):  
Mathematical Modeling ◽  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Endothelial Nitric Oxide Synthase ◽  
Cellular Models ◽  
No Signaling ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide

We used mathematical modeling to investigate nitric oxide (NO)-dependent vasodilatory signaling in the arteriolar wall. Detailed continuum cellular models of calcium (Ca2+) dynamics and membrane electrophysiology in smooth muscle and endothelial cells (EC) were coupled with models of NO signaling and biotransport in an arteriole. We used this theoretical approach to examine the role of endothelial hemoglobin-α (Hbα) as a modulator of NO-mediated myoendothelial feedback, as previously suggested in Straub et al. ( Nature 491: 473–477, 2012). The model considers enriched expression of inositol 1,4,5-triphosphate receptors (IP3Rs), endothelial nitric oxide synthase (eNOS) enzyme, Ca2+-activated potassium (KCa) channels and Hbα in myoendothelial projections (MPs) between the two cell layers. The model suggests that NO-mediated myoendothelial feedback is plausible if a significant percentage of eNOS is localized within or near the myoendothelial projection. Model results show that the ability of Hbα to regulate the myoendothelial feedback is conditional to its colocalization with eNOS near MPs at concentrations in the high nanomolar range (>0.2 μM or 24,000 molecules). Simulations also show that the effect of Hbα observed in in vitro experimental studies may overestimate its contribution in vivo, in the presence of blood perfusion. Thus, additional experimentation is required to quantify the presence and spatial distribution of Hbα in the EC, as well as to test that the strong effect of Hbα on NO signaling seen in vitro, translates also into a physiologically relevant response in vivo. NEW & NOTEWORTHY Mathematical modeling shows that although regulation of nitric oxide signaling by hemoglobin-α (Hbα) is plausible, it is conditional to its presence in significant concentrations colocalized with endothelial nitric oxide synthase in myoendothelial projections. Additional experimentation is required to test that the strong effect of Hbα seen in vitro translates into a physiologically relevant response in vivo

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