Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.6.99.1 (NADPH-diaphorase)
 3,903 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Reflux nephropathy (RN) is recognized as a major cause of end-stage renal failure in children and young adults. Inhibition of nitric oxide (NO) exacerbates and enhanced production ameliorates tubulointerstitial fibrosis (TIF) in experimental obstructive uropathy. NO is synthesised by NO synthase (NOS), three distinct isoforms of which have been identified: inducible (iNOS), endothelial (eNOS), and neuronal (nNOS). It has been reported that iNOS induces immunologic injury to glomerular cells and enhances accumulation of extracellular matrix in the glomerulus and tubulointerstitial space. Furthermore, it has been suggested that nNOS and eNOS have beneficial effects in ameliorating TIF. We investigated the expression of different isoforms of NOS in severe refluxing kidneys in order to further understand the pathogenesis of RN in kidney specimens from nine children with severe RN obtained at nephrectomy. Control material included normal kidney specimens from three adult patients undergoing partial nephrectomy for small kidney tumours. Histochemistry for NO was performed using nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase. Single-label immunofluorescence histochemistry was carried out using polyclonal antibodies to nNOS, iNOS, eNOS, and transforming growth factor (TGF)-beta 1 employing laser-scanning confocal microscopy. The TUNEL method was used to assess tubular apoptosis. Strong NADPH staining was observed in the proximal tubules of RN kidneys compared to controls, where there was weak staining. Control kidneys demonstrated weak immunoreactivity for iNOS in the proximal tubules and a lack of immunoreactivity for nNOS and eNOS. RN kidneys demonstrated strong immunoreactivity for nNOS in the tubulointerstitial space, for eNOS in the glomerulus, and for iNOS in the glomerulus and proximal tubules. Strong immunoreactivity for TGF beta 1 was seen in the glomerulus and proximal tubules identical to iNOS. Increased immunoreactivity for iNOS and TGF-beta 1 strongly correlated with the severity of apoptosis in RN. Our data demonstrate that NO derived from nNOS, iNOS, and eNOS is strongly expressed in RN. The selective shunting of NO via iNOS may induce renal fibrosis in RN. The upregulation of nNOS and eNOS in RN appears to be a compensatory mechanism of ameliorating TIF.
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PMID:The role of nitric oxide in reflux nephropathy. 1247 80

We investigated the role of nitric oxide (NO)-guanosine 3',5'-cyclic monophosphate (cGMP) signaling in the regulation of rabbit clitoral cavernosum (CC) tone. Tension measurements, reverse transcriptase-polymerase chain reaction (RT-PCR), Western blotting, and NADPH-diaphorase staining were performed in CC. In the precontracted CC strips with phenylephrine (10(-5) M), acetylcholine (ACh) relaxed, dependent on dosage. Pretreatment with atropine, N(omega) nitro-L-arginine-methyl ester (NAME) or 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ), guanylate cyclase inhibitor abolished the ACh-induced relaxations, but tetrodotoxin (TTX) did not. Sodium nitroprusside relaxed the strips in the presence of atropine and NAME, but not in the presence of ODQ. Electrical field stimulation (EFS) relaxed the strips dependent on stimulus strength. Pretreatment with TTX, NAME, or ODQ abolished the EFS-induced relaxation, but atropine did not. L-Arginine partially restored the inhibited response to ACh and EFS. The inducible NO synthase (iNOS) and neuronal NOS (nNOS) mRNAs and iNOS and endothelial NOS (eNOS) proteins were identified in the CC. NADPH-diaphorase staining revealed the positivity on the nerve trunks and fine nerve fibers in the CC. Finally, results demonstrate that the nNOS, ENOS, and the NO-cGMP signaling pathway are involved in the regulation of clitoral tumescence.
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PMID:Nitric oxide-cyclic GMP signaling pathway in the regulation of rabbit clitoral cavernosum tone. 1248 13

Nitric oxide (NO) production in the sensory neurons of the rad nodose ganglion was studied by examining the distribuiotn of NO synthase (NOS) by use of NADPH diaphorase (NADPHD) histochemistry and immunohistochemistry ofr the presence of isoformes of NOS: neuronal (nNOS), endothelial (eNOS) and the inducible isoform (iNOS). Distribution and changes in NO production during acute hypoxia were studied in vital vibratome sections with the fluorescent marker for NO, diaminotriazolofluorescein (DAF-2T). Furthermore, changes in reactive oxygen species (ROS) in vibratome slices were examined utilizing 2',7'-dichlorofluorescein (DCF). By use of these histochemical methods, a positive NADPH reaction and positive immunoreactivity for eNOS were noted in all neurons observed. While for nNOS immunoreactivity, both strongly positive cells but also many negative cells are seen., no iNOS immunoreactive cells were observed. In vital vibratome slices, a dot-like distribution of fluorescence for DAF-2T, indicating production of NO, was observed in the nodose ganglion cells. Neurons exposed to hypoxia showed stronger DAF-2T fluorescence than cells exposed to normoxia, indicating an increased production of NO during hypoxia. When Ca(2+) was removed from the incubation buffer, the intensity of fluorescence for DAF-2T decreased but did not disappear completely. Using a photoconversion technique, DAF-2T was localized in the inner membrane of mitochondria in the ganglion cells by electron microscopy. The level of DCF signals for detection of ROS was higher in neurons incubated in the normoxic medium than those incubated under conditions of hypoxia. Nerve cells exposed to hypoxia followed by reoxygenation (3 min in normoxic conditions) showed higher fluorescence for DCF than those exposed to normoxia. The results of the present study demonstrate clearly that the basal production of NO in viscerosensory neurons is increased during hypoxia and is due to the isoform eNOS rather than nNOS, moreover, that ROS is augmented by reoxygenation but not during hypoxia.
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PMID:Altered production of nitric oxide and reactive oxygen species in rat nodose ganglion neurons during acute hypoxia. 1253 70

Cellular localization patterns of NOS isoforms 1 and 3 (nNOS and eNOS, respectively) in the mammalian heart under basal (non-stimulated) working conditions are still a matter of discussion. Therefore, this issue was reinvestigated in rats using RT-PCR, Western blotting, catalytic histochemistry, immunohistochemistry and image analysis. Tongue and extensor digitorum longus muscles served as positive controls for NOS-1 and NOS-3. RT-PCR revealed NOS-1 mRNA and NOS-3 mRNA in atria and ventricles. Western blotting showed NOS-1 protein in atria and NOS-3 protein in the walls of both heart chambers. Localization of the activity of urea-resistant (and therefore specific) NADPH diaphorase (NADPH-D) and NOS-1 immunohistochemistry showed that NOS-1 is present in the sarcolemma region of a subpopulation of atrial cardiomyocytes but not in working and impulse-conducting cardiomyocytes of atria and ventricles. Atrial natriuretic peptide (ANP) immunohistochemistry revealed that a minority of the NOS-1-expressing atrial cardiomyocytes are myoendocrine cells. eNOS immunostaining was present in endothelial cells of capillaries of the conducting and working myocardium and endocardial cells. Image analysis of the activity of urea-resistant NOS diaphorase showed that NOS-1 activity is lower in the sarcolemma region of atrial cardiomyocytes than in that of tongue and extensor digitorum longus myofibers. These data suggest that, in the non-stimulated rat heart. NOS-1 is expressed in a subpopulation of atrial cardiomyocytes including myoendocrine cells, and that NOS-3 is expressed in the vascular and endocardial endothelium.
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PMID:Localization of NOS-1 in the sarcolemma region of a subpopulation of atrial cardiomyocytes including myoendocrine cells and NOS-3 in vascular and endocardial endothelial cells of the rat heart. 1266 87

Coronary and valvular heart disease during diabetes mellitus (DM) are major contributors of morbidity and mortality in the diabetic population. Relatively little atention has been given to the study of heart valve nerve structures in different pathological processes. In this study we have demonstrated the presence of possible morphological alterations in vessels of the anterior cusp of the rat mitral valve during 8-12 weeks DM. A histochemical method was used for the detection of NADPH-diaphorase (NADPH-d), which is the indirect NO-synthase marker. Arterioles and fine capillaries were localized in the attachment zone of the anterior cusp. Perivascular nerve fibres were identified running in the tunica adventitia. A marked dilatation of the vessels was seen in diabetes in comparison with control samples. No NADPH-d positive nerve fibres were observed in the tunica adventitia. It can be presumed that metabolic changes in the vessel walls during DM reflect modified neurotransmission of NO by means of their excessive overproduction of NOS (endothelial--eNOS) in endothelial cells. (Fig. 6, Ref. 32.).
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PMID:Alterations of the vessel wall innervation during diabetes mellitus. 1269 74

There are controversies about the injury of the contralateral testis during unilateral testicular torsion (UTT). An autonomic reflex arc between bilateral testes has been proposed. The authors focused on the involvement of nitric oxide (NO) in the contralateral testis during UTT. Eight-week-old male Wistar rats underwent unilateral torsion (1 h)-detorsion (up to 24 h). NO synthase (NOS) activity was detected as NADPH-diaphorase activity after fixation by paraformaldehyde. N-nitro-L-Arginine methyl ester (L-NAME, 20 mg/kg) was injected intravenously to the other group of rats. To evaluate the testicular injury, proteolysis of alpha-fodrin production was detected by Western blotting. Apoptosis of the germ cells was evaluated by TUNEL. Long-term effect on spermatogenesis was evaluated by flow cytometry at 60 days after UTT. Transient activation of NOS was detected following the proteolysis of alpha-fodrin in the contralateral testis. L-NAME inhibited these alterations. NADPH-diaphorase activity and eNOS immunoreactivity were co-localized in the endothelial cells. These reactions were not observed in other organs. There was neither enhanced apoptosis nor deteriorated spermatogenesis in the contralateral testis during and 60 days after UTT. In the contralateral testis, eNOS-derived NO regulates the vasomotor function against unilateral testicular torsion, whereas it acts slightly cytotoxic. These results suggest the possible involvement of a testis-specific neurovasomotor reflex between the bilateral testes.
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PMID:Activation of endothelial nitric oxide synthase in contralateral testis during unilateral testicular torsion in rats. 1274 96

Nitric oxide (NO), a highly reactive free radical is involved in vasodilation, neurotransmission, hormone secretion, and reproduction. Since all known nitric oxide synthase (NOS) isoforms possess NADPH-diaphorase (NADPH-d) activity, NADPH-d histochemistry was used as a commonly accepted procedure for NOS identification. The aim of our study was to determine the cellular localization of NADPH-d, eNOS, and iNOS in the porcine uterus and the correlation between NADPH-d and NOS activity in the early, middle, late luteal, and follicular phase of the estrous cycle. Light-microscopic observations of the sections revealed the differential expression of the NADPH-d in the analyzed stages of the estrous cycle. The most intense staining was observed in the luminal epithelium in the late luteal phase and in some groups of the endometrial glands in all studied stages. Positive reaction was also found in the endothelial cells of blood vessels and in the myometrium itself. Immunostaining for eNOS was observed in the luminal and glandular epithelium in all studied stages, but no clear fluctuations were observed. The endothelium of both endometrial and myometrial blood vessels displayed pronounced eNOS immunostaining. Strong iNOS staining was observed in the luminal epithelium in the late luteal and follicular phase and in selected groups of endometrial glands. Thus, only NADPH-d and iNOS undergo cyclic changes in the studied stages of the estrous cycle. The differential expression of NADPH-d/NOS in the porcine uterine horn during the estrous cycle suggests a role for NO in modulating uterine function.
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PMID:Localization and correlation between NADPH-diaphorase and nitric oxide synthase isoforms in the porcine uterus during the estrous cycle. 1595 92

Nitrosative stress plays a role in calcium oxalate stone formation, as nitrosated proteins have been identified in stone formers. Nitric oxide (NO(*)), the common precursor for reactive nitrogen species, is synthesized in the juxtaglomerular apparatus of the kidneys. The present study is aimed to determine the role of nitric oxide synthase (NOS) in an experimental hyperoxaluric condition by histological and biochemical techniques. Hyperoxaluria was induced by 0.75% ethylene glycol in drinking water. L-arginine (L-arg) was supplemented at a dose of 1.25 g/kg body weight orally for 28 days. Nitric oxide metabolites (NOx), protein content in the urine and lipid peroxidation in the kidney were determined at the end of the experimental period. Histopathological examination of the rat kidneys was then carried out. NADPH-diaphorase and eNOS expression studies were carried out in control and hyperoxaluric rat kidneys using histochemical and immunohistochemical techniques. Significant amounts of NOx were present in the urine of hyperoxaluric animals when compared to control rats. Histopathological examinations revealed membrane injury, tubular dilatation and edema in the hyperoxaluric rats, whereas co-supplementation of L-arg to the hyperoxaluric rats significantly reduced these changes. The results of histochemical analysis for NADPH-diaphorase staining demonstrate the role of NOS in hyperoxaluric rats. Hyperoxaluric rats showed intense staining for NADPH-diaphorase when compared to control and L-arg co-supplemented hyperoxaluric rats. Immunohistochemical demonstration confirmed that eNOS expression was markedly increased in L-arg supplemented rats, when compared to EG treated rat kidney sections. Thus, from the present study, we conclude that supplementation of L-arg to the hyperoxaluric animals minimizes the cellular injury mediated by ethylene glycol, prevents oxidative/nitrosative damage to the membranes and reduces the incidence of calcium oxalate stone formation.
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PMID:Detection of endothelial nitric oxide synthase and NADPH-diaphorase in experimentally induced hyperoxaluric animals. 1600 48

In mammals, much is understood about the endothelial and neural NO control mechanisms in the vasculature. In contrast, NO control of blood vessels in lower vertebrates is poorly understood, with the majority of research focusing on the presence of an endothelial NO system; however, its presence remains controversial. This study examined the mechanisms by which NO regulates the large blood vessels of non-mammalian vertebrates. In all species examined, the arteries and veins contained a plexus of NOS-positive perivascular nerves that included nerve bundles and fine, varicose nerve terminals. However, in the large arteries and veins of various species of fishes and amphibians, no anatomical evidence was found for endothelial NOS using both NADPH-diaphorase and eNOS immunohistochemistry. In contrast, perinuclear NOS staining was readily apparent in blue-tongue lizard, pigeon and rat, which suggested that eNOS first appeared in reptiles. Physiological analysis of NO signalling in the vascular smooth muscle of short-finned eel and cane toad could not find any evidence for endothelial NO signalling. In contrast, it appears that activation of the nitrergic vasomotor nerves is responsible for NO control of the blood vessels.
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PMID:Nitric oxide control of lower vertebrate blood vessels by vasomotor nerves. 1613 37

Diabetes-induced erectile dysfunction is one of the most prevalent complications of diabetes in males. alpha-Lipoic acid (ALA) and its reduced form, dihydrolipoic acid, are powerful antioxidants. Data strongly suggest that, because of its antioxidant properties, ALA is particularly suited to the prevention and/or treatment of diabetic complications that arise from overproduction of reactive oxygen and nitrogen. The aim of this study was to investigate the localization of nitric oxide synthetase (NOS) in normal and diabetic rat cavernous smooth muscles and to examine the effects of ALA on them. Rats were divided into four groups: control, diabetic, diabetic plus ALA, and ALA only. Penile tissues were taken 15 days after drug application and examined histochemically and immunohistochemically. Comparison of the control and diabetic groups revealed that the axons of nerve cells were not identified with Masson trichrome in the diabetic group, whereas in the control group NOS localization and immunostaining (endothelial NOS [eNOS]) were normal. Diabetic rats administered ALA showed improvement in Masson trichrome, nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d) and eNOS localization compared with untreated diabetic rats. Although there was no difference between the control group and the group administered ALA only, we observed an increase in NADPH-d and eNOS. In erection, eNOS and neuronal NOS (nNOS) may have a significant role. In pathologic conditions, erectile dysfunction may occur as a result of an increase in inducible macrophage-type NOS (iNOS). ALA plays an important role in treatment of erectile dysfunction by decreasing iNOS and increasing other isoforms of NOS.
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PMID:The effects of alpha-lipoic acid on nitric oxide synthetase dispersion in penile function in streptozotocin-induced diabetic rats. 1637 81


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