Nitrate Synthesis in the Germfree and Conventional Rat

Green, Laura C.; Tannenbaum, Steven R.; Goldman, Peter

doi:10.1126/science.6451927

Cited by 486 publications

(198 citation statements)

References 9 publications

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“…The basal levels of plasma nitrate and nitrite may de pend on the amount of intake of nitrogen compounds and on the anaerobic bacterial flora within the intestine (Hong et al, 1980;Green et al, 1981). We, therefore, used spe cific pathogen-free male Sprague-Dawley rats purchased from the same feeder and fed by the same standard food and water.…”

Section: Methodsmentioning

confidence: 99%

Elevation of Plasma Nitric Oxide End Products during Focal Cerebral Ischemia and Reperfusion in the Rat

Kumura

Kosaka

Shiga

et al. 1994

J Cereb Blood Flow Metab

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Summary:We investigated the alterations in the stable end products of nitric oxide, i.e., nitrate and nitrite, in the plasma during and after rat focal cerebral ischemia by an automated procedure based on the Griess reaction. At 2 h of middle cerebral artery (MCA) occlusion, plasma ni trate/nitrite levels were significantly higher (53 ± 8 ILM, mean ± SD, n = 5, p < 0.05) than in rats with sham operation (36 ± 9 ILM, n = 5), and were mildly elevated at 4 h of MCA occlusion (42 ± 9 ILM, n = 5, n.s.). At 30 min of reperfusion after 2 h of MCA occlusion, plasma nitrate/nitrite levels were more markedly elevated (72 ± 7 ILM, n = 5, p < 0.01 vs. sham operation), but were mod erately elevated at 2 h of reperfusion after 2 h of MCA occlusion (61 ± 10 ILM, n = 5, p < 0.05). Plasma nitrite To date, nitric oxide is considered both a free rad ical, an endothelium-derived relaxing factor, and a neurotransmitter (Palmer et aI., 1987;Garthwaite, 1991). In view of the fact that NOS is distributed within the brain, nitric oxide could be deeply in volved in the pathophysiology of cerebral ischemia Received July 9, 1993; final revision received September 7, 1993; accepted October 6, 1993.Address correspondence and reprint requests to Dr. Eiji Ku mura, Department of Physiology, Osaka University Medical School, 2-2 Yamadaoka, Suita, Osaka 565, Japan.Abbreviations used: ANOVA, analysis of variance; L-NAME, �-nitro-L-arginine methyl ester; MeA, middle cerebral artery; NOS, nitric oxide synthase. 487 levels were not changed during these experimental peri ods. Administration of 20 mg/kg of NG-nitro-L-arginine methyl ester (L-NAME) significantly decreased plasma nitrate/nitrite as well as nitrite at 30 min of reperfusion after 2 h of MCA occlusion (n = 5), but 2 mg/kg of L-NAME did not (n = 3). The effect of 20 mg/kg of L-NAME on plasma nitric oxide end products was re versed by the simultaneous administration of 200 mg/kg of L-arginine (n = 3), but not D-arginine (n = 3). The present study suggests that the L-arginine-nitric oxide pathway is activated during acute cerebral ischemia and reperfusion.

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Section: Methodsmentioning

confidence: 99%

Elevation of Plasma Nitric Oxide End Products during Focal Cerebral Ischemia and Reperfusion in the Rat

Kumura

Kosaka

Shiga

et al. 1994

J Cereb Blood Flow Metab

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“…The nitrate (NO 3 -) present in the serum samples obtained from infected and TNF- § mAb-treated animals was reduced to nitrite with nitrate reductase and the nitrite concentration was determined by the Griess method [27].…”

Section: Determination Of Serum Nitrate Concentrationmentioning

confidence: 99%

TNF‐α mediates the induction of nitric oxide synthase in macrophages but not in neutrophils in experimental cutaneous leishmaniasis

et al. 2003

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Leishmania major infection in C57BL/6 mice is controlled by the activation of a Th1 response and nitric oxide (NO) production by macrophages. TNF- § is considered one of the most important cytokines involved in this response. In the present study, we investigated the expression of nitric oxide synthase (iNOS) in the inflammatory cells present in the lesion and draining lymph nodes, and the cytokine production by lymph node cells in animals treated with anti-TNF- § . Our results demonstrated that mice treated with anti-TNF- § presented an increase in the number of parasites and the size of lesion, but they were able to control the infection. The increase in the lesion size correlated to the reduction of iNOS activity in the draining lymph nodes. Furthermore, the anti-TNF- § treatment also reduced the expression of iNOS in the macrophages, but did not affect the iNOS expression in the neutrophils. The anti-TNF- § mAb did not reduce the iNOS expression in IFN-+ -stimulated L. major infected neutrophils in vitro. Anti-TNF- § mAb treatment caused an increase in the production of IFN-+ and IL-10 by the lymph node cells from infected mice. Consequently, these results suggest that neutrophils do not respond to anti-TNF- § treatment and might be a source of NO to control L. major infection under these experimental conditions.

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“…Also, extensive research was conducted (e.g. [25]) to elucidate the metabolic basis for endogenous nitrate synthesis that had been discovered in humans and rats [26][27][28]. Key discoveries in 1987 included reports that arginine is the precursor for mammalian nitrite\nitrate synthesis [29] and that nitric oxide (NO) is the endothelium-derived relaxing factor [30,31].…”

Section: Introductionmentioning

confidence: 99%

Arginine metabolism: nitric oxide and beyond

Morris

1998

Biochemical Journal

2,425

2,036

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Arginine is one of the most versatile amino acids in animal cells, serving as a precursor for the synthesis not only of proteins but also of nitric oxide, urea, polyamines, proline, glutamate, creatine and agmatine. Of the enzymes that catalyse rate-controlling steps in arginine synthesis and catabolism, argininosuccinate synthase, the two arginase isoenzymes, the three nitric oxide synthase isoenzymes and arginine decarboxylase have been recognized in recent years as key factors in regulating newly identified aspects of arginine metabolism. In particular, changes in the activities of argininosuccinate synthase, the arginases, the inducible isoenzyme of nitric oxide synthase and also cationic amino acid transporters play major roles in determining the metabolic fates of arginine in health and disease, and recent studies have identified

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Nitrate Synthesis in the Germfree and Conventional Rat

Abstract: Metabolic balance studies show that germfree and conventional Sprague-Dawley rats synthesize nitrate. Equivalent results for germfree and conventional rats eliminate the microflora as obligatory components of nitrate production. Nitrate synthesis appears to be a mammalian process.

Cited by 486 publications

References 9 publications

Elevation of Plasma Nitric Oxide End Products during Focal Cerebral Ischemia and Reperfusion in the Rat

Elevation of Plasma Nitric Oxide End Products during Focal Cerebral Ischemia and Reperfusion in the Rat

TNF‐α mediates the induction of nitric oxide synthase in macrophages but not in neutrophils in experimental cutaneous leishmaniasis

Arginine metabolism: nitric oxide and beyond

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