scholarly journals The Cerebral Metabolic Consequences of Nitric Oxide Synthase Deficiency: Glucose Utilization in Endothelial and Neuronal Nitric Oxide Synthase Null Mice

1999 ◽  
Vol 19 (2) ◽  
pp. 144-148 ◽  
Author(s):  
Susan E. Browne ◽  
Cenk Ayata ◽  
Paul L. Huang ◽  
Michael A. Moskowitz ◽  
M. Flint Beal

Nitric oxide has multiple physiologic roles in the CNS. Inhibiting nitric oxide synthesis might therefore alter functional activity within the brain. We used [14C]-2-deoxyglucose in vivo autoradiography to measure local CMRglc in “knockout” mice lacking the genes for either the endothelial (eNOS) or neuronal (nNOS) isoforms of nitric oxide synthase, and in the progenitor strains (SV129, CS7B1/6). Glucose utilization levels did not significantly differ between nNOS and eNOS knockout mice and C57B1/6 mice in any of the 48 brain regions examined, but were relatively lower in some subcortical regions in SV129 mice.

2000 ◽  
Vol 72 (6) ◽  
pp. 1001-1006 ◽  
Author(s):  
D. Desaiah ◽  
S. L. N. Reddy ◽  
S. Z. Imam ◽  
S. F. Ali

Methamphetamine (METH) is a potent psychostimulant known to produce neurotoxicity. The dopaminergic pathway is particularly sensitive to METH. Recent studies showed that 7-nitroindazole (7-NI), a selective inhibitor of neuronal nitric oxide synthase (nNOS), provided protection against METH neurotoxicity both in vitro and in vivo. The present studies were conducted to determine the nNOS activity in various regions of the brain of young adult male Sprague-Dawley rats treated with different doses of METH. Rats were injected ip with 5, 10, 20, and 40 mg/kg and 24 h after the rats were sacrificed and the brain regions (hippocampus, frontal cortex, and cerebellum) were quickly dissected. The cytosolic fractions were prepared, and the nNOS activity was determined using the 3H-citrulline assay. The results showed that nNOS activity was significantly increased in all three brain regions of rats treated with METH. The increase was dose dependent reaching a maximum of 40-100% over the control values. Rats treated with 7NI 30 min prior to METH injection provided protection against the toxicity and also showed a reduction of nNOS activity. The activation of nNOS is known to increase the synthesis of NO which is involved in the regulation of several neurotransmitter pathways including catecholaminergic system. Reducing the METH-induced production of NO by pretreatment with selective inhibitor of nNOS, 7-NI, provided protection against METH neurotoxicity.


Circulation ◽  
1997 ◽  
Vol 96 (9) ◽  
pp. 3104-3111 ◽  
Author(s):  
Yoshihiro Fukumoto ◽  
Hiroaki Shimokawa ◽  
Toshiyuki Kozai ◽  
Toshiaki Kadokami ◽  
Kouichi Kuwata ◽  
...  

1999 ◽  
Vol 17 (1) ◽  
pp. 45-55 ◽  
Author(s):  
A.E.-D El-Husseini ◽  
J Williams ◽  
P.B Reiner ◽  
S Pelech ◽  
S.R Vincent

2001 ◽  
Vol 132 (3) ◽  
pp. 677-684 ◽  
Author(s):  
Angeles Alvarez ◽  
Laura Piqueras ◽  
Regina Bello ◽  
Amparo Canet ◽  
Lucrecia Moreno ◽  
...  

2011 ◽  
Vol 301 (3) ◽  
pp. H721-H729 ◽  
Author(s):  
Katsuhiko Noguchi ◽  
Naobumi Hamadate ◽  
Toshihiro Matsuzaki ◽  
Mayuko Sakanashi ◽  
Junko Nakasone ◽  
...  

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.


ChemInform ◽  
2010 ◽  
Vol 32 (32) ◽  
pp. no-no
Author(s):  
Haydn Beaton ◽  
Nigel Boughton-Smith ◽  
Peter Hamley ◽  
Anant Ghelani ◽  
David J. Nicholls ◽  
...  

1995 ◽  
Vol 181 (1) ◽  
pp. 63-70 ◽  
Author(s):  
N K Worrall ◽  
W D Lazenby ◽  
T P Misko ◽  
T S Lin ◽  
C P Rodi ◽  
...  

The role of nitric oxide in the immune response to allogeneic tissue was explored in an in vivo cardiac transplant model in the rat. Nitric oxide production during organ rejection was demonstrated by elevations in systemic serum nitrite/nitrate levels and by electron paramagnetic resonance spectroscopy. Messenger RNA for the inducible nitric oxide synthase enzyme was detected in the rejecting allografted heart, but not in the nonrejecting isografted heart. The enzyme was demonstrated to be biologically active by the in vitro conversion of L-arginine to L-citrulline and was immunohistochemically localized to the infiltrating inflammatory cells. Treatment with aminoguanidine, a preferential inhibitor of the inducible nitric oxide synthase isoform, prevented the increased nitric oxide production in the transplanted organ and significantly attenuated the pathogenesis of acute rejection. Aminoguanidine treatment prolonged graft survival, improved graft contractile function, and significantly reduced the histologic grade of rejection. These results suggest an important role for nitric oxide in mediating the immune response to allogeneic tissue. Inhibition of inducible nitric oxide synthase may provide a novel therapeutic modality in the management of acute transplant rejection and of other immune-mediated processes.


Sign in / Sign up

Export Citation Format

Share Document