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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Neuronal nitric oxide synthase (nNOS) mRNA levels and NADPH diaphorase (NADPH-d) staining were compared in the frontal cortex, visual cortex and hippocampus (dentate gyrus and CA subfields of Ammon's horn) of five Alzheimer's disease (AD) and six control brains. The cellular abundance of nNOS mRNA was quantified by in-situ hybridisation using 35S-labelled antisense oligonucleotides complementary to the human nNOS sequence. Although the mean level of nNOS expression was decreased in all three regions in AD cases as compared to controls, it did not reach significance. Neurones positively labelled for nNOS mRNA and neurones positive for NADPH-d histochemistry displayed similar distribution in control and AD cases. In AD brains the density of neurones having detectable levels of nNOS mRNA was significantly decreased in the white matter underlying the frontal cortex (P < 0.05) but not in the frontal cortex gray matter; no change was observed in the gray or white matter of the visual cortex in AD. The number of cells expressing detectable levels of nNOS mRNA in the hippocampus was also significantly decreased (P < 0.05) in AD. The density of NADPH-d-positive cells was not significantly decreased in the gray or white matter of the frontal or visual cortices in AD compared to controls; however, the number of NADPH-d-positive cells was significantly decreased in the hippocampus (P < 0.01). These data indicate that although the cellular abundance of nNOS mRNA is not significantly decreased in these three regions in AD, there is a significant decrease in the number of cells expressing detectable levels of nNOS mRNA in the white matter underlying the frontal cortex and in the dentate gyrus and CA subfields of the hippocampus in AD. Furthermore, there was also a significant decrease in the number of NADPH-d-positive cells in the dentate gyrus and CA subfields of the hippocampus in AD as compared to controls. These results suggest specific populations of nNOS/NADPH-d cells in the white matter underlying the frontal cortex and in the hippocampus are vulnerable in AD. The implications of these findings are discussed.
Brain Res Mol Brain Res 1996 Sep 05
PMID:Neuronal nitric oxide synthase (nNOS) mRNA expression and NADPH-diaphorase staining in the frontal cortex, visual cortex and hippocampus of control and Alzheimer's disease brains. 888 32

Lesion-induced induction of neuronal nitric oxide synthase (nNOS) was examined in the rat cerebellum. The stab-lesioned cerebellar cortex was examined with NADPH-diaphorase (NADPH-d) histochemistry and in situ hybridization using nNOS cRNA probe at 1, 3, 7, 14, 35 days post-lesion. NADPH-d- and nNOS mRNA-positive Purkinje cells appeared adjacent to the lesion by 3 days after the lesion. The area of distribution expanded and the number of positive cells increased at 7 days after the lesion, and at 14 days post-lesion, shrunken NADPH-d-positive Purkinje cells with irregular surface appeared. NADPH-d activity and nNOS mRNA signal could not be detected in Purkinje cells after 35 days post-lesion. Combined NADPH-d histochemistry and in situ hybridization using glutamic acid decarboxylase (GAD) cRNA probe revealed that nNOS-expressing Purkinje cells showed fewer GAD mRNA signals than those in normal Purkinje cells. The atrophic contour and the lower expression of GAD mRNA signals in NADPH-d positive Purkinje cells suggest that nNOS is expressed under a degenerating process.
Brain Res Mol Brain Res 1997 Mar
PMID:Lesion-induced neuronal nitric oxide synthase in Purkinje cells of the rat cerebellar cortex: histochemical and in situ hybridization study. 907 64

Our understanding of how human glial cells are induced to produce nitric oxide and how the production is regulated may allow us to better design therapeutic strategies for treating inflammatory diseases of the central nervous system in man. Cultures of human fetal astrocytes and microglia produce inducible nitric oxide synthase and nitric oxide in response to Interferon gamma and Interleukin 1 beta. The mRNA for the enzyme was induced by 2 h and returned to baseline by day 2; the protein was expressed by 24 h and was present in cells for the entire 7 days of culture. Nitric oxide was not seen in cell supernatants until day 3 reaching a peak by day 7. Footprints of nitric oxide production such as NADPH diaphorase and nitrotyrosine staining as well as cGMP production were not significantly above background until day 3 to day 4, rising steadily until day 7. These data suggest that while the type II nitric oxide synthase is induced in human glial cells within 24 h of stimulation, it is not a functionally active enzyme until 48-72 h later, implying that there is a posttranslational regulation of the enzyme limiting nitric oxide production in these cells.
Mol Psychiatry 1997 Mar
PMID:The kinetics and regulation of the induction of type II nitric oxide synthase and nitric oxide in human fetal glial cell cultures. 910 31

A high proportion of neurons in the cerebellum and in cholinergic brainstem nuclei stain positive for nicotinamide adenine dinucleotide phosphate-diaphorase (NADPHd), which is a nitric oxide synthase (NOS). Recent evidence suggests that schizophrenia may involve increased numbers of NADPHd-stained neurons in different areas of the subcortex. This led us to examine the actual concentration of NOS in postmortem brain specimens of cerebellum, and the relevant regions of brainstem tegmentum, to see if NOS concentrations were also increased in schizophrenia. Postmortem brain tissue was obtained at autopsy from schizophrenics and controls who did not have other brain disease. In patients with schizophrenia, NOS concentration was higher.
Mol Chem Neuropathol 1996 Apr
PMID:Nitric oxide synthase (NOS) in schizophrenia: increases in cerebellar vermis. 914 13

The leukocyte iodonitrotetrazolium violet (INT) reductase activity of disrupted bovine polymorphonuclear neutrophils is closely associated with the activation of the O2(-)-generating NADPH oxidase in a cell-free system. It is dependent upon NADPH, cytosolic factors, and amphiphiles (such as arachidonate), the same factors required for O2- generation. Both O2- generation and INT reductase activity are inhibited by phenylarsine oxide, an inhibitor of the activation of the NADPH oxidase [Li, J., & Guillory, R. J. (1997) J. Biochem. Mol. Biol. Biophys. (in press)]. In this report, the INT diaphorase activity of disrupted bovine polymorphonuclear neutrophils is shown to be resolved by DEAE-Sepharose chromatography into two fractions: an NADPH-cytochrome c reductase-containing fraction and a cytochrome b558-associated fraction. The diaphorase activity in the NADPH-cytochrome c reductase-containing portion is not dependent upon the presence of an amphiphile or phospholipid and is not associated with O2- generation. Upon incorporation into liposomes, the cytochrome b558-containing fraction demonstrates high O2- and INT reductase activities in the presence of cytosolic factors. Both O2- generation and INT reductase activities are SDS and FAD dependent and further stimulated by GTPgammaS. Phenylarsine oxide inhibits both O2- generation and INT reductase activities when added prior to activation by SDS. With the cytochrome b-containing liposomes, the Km values (O2- formation) for NADPH and NADH are 27.2 microM and 810 microM, and for INT reductase the Km values are 27.5 microM and 1017 microM, respectively. Under anaerobic conditions and thus in the absence of O2- formation, the NADPH-dependent INT reductase activity does not change, indicating that the dye reduction is not due to its direct reduction by O2 anion but is an intrinsic property of the superoxide-generating NADPH oxidase. Cytochrome b558 is the essential component of the NADPH oxidase and contains all the redox centers necessary for electron flow between NADPH and oxygen. The correlation of the activation and inhibition patterns for O2- generation and INT reduction by cytochrome b558 incorporated into artificial liposomes strongly indicates that the two activities are associated with the same membrane protein, cytochrome b558.
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PMID:Purified leukocyte cytochrome b558 incorporated into liposomes catalyzes a cytosolic factor dependent diaphorase activity. 915 36

Human spermatozoa possess a specialized capacity to generate reactive oxygen species (ROS) that is thought to be of significance in the redox regulation of sperm capacitation (De Lamirande and Gagnon, 1993; Aitken et al., 1995). However, the mechanisms by which ROS are generated by these cells are not understood. In this study we have examined the possible significance of NADPH as a substrate for ROS production by human spermatozoa. Addition of NADPH to viable populations of motile spermatozoa induced a sudden dose-dependent increase in the rate of superoxide generation via mechanisms that could not be disrupted by inhibitors of the mitochondrial electron transport chain (antimycin A, rotenone, carbonyl cyanide m-chlorophenylhydrazone [CCCP], and sodium azide), diaphorase (dicoumarol) xanthine oxidase (allopurinol), or lactic acid dehydrogenase (sodium oxamate). However, NADPH-induced ROS generation could be stimulated by permeabilization and was negatively correlated with sperm function. Both NADH and NADPH were active electron donors in this system, while NAD+ and NADP+ exhibited little activity. Stereo-specificity was evident in the response in that only the beta-isomer of NADPH supported superoxide production. The involvement of a flavoprotein in the electron transfer process was indicated by the high sensitivity of the oxidase to inhibition by diphenylene iodonium and quinacrine. These results indicate that NAD(P)H can serve as an electron donor for superoxide generation by human spermatozoa and present a simple strategy for the production of motile populations of free radical generating cells with which to study the significance of these molecules in the control of normal and pathological sperm function.
Mol Reprod Dev 1997 Aug
PMID:Reactive oxygen species generation by human spermatozoa is induced by exogenous NADPH and inhibited by the flavoprotein inhibitors diphenylene iodonium and quinacrine. 921 32

Nitric oxide synthase (NOS) is responsible for the biological production of nitric oxide (NO) in several organs. NOS activity has also been localized in the reproductive tract, although direct evidence for its presence in the human or bovine oviduct is still lacking. In the present study, four different techniques were used to identify the presence of NOS activity in human (n = 11) and bovine (n = 9) oviduct: (i) conversion of [3H]-L-arginine to [3H]-L-citrulline; (ii) production of nitrite/nitrate (NO2/NO3; stable NO metabolites); (iii) identification of NADPH-diaphorase activity; and (iv) immunostaining with antiserum to endothelial NOS. Cytosolic extracts from human ampullary segments of the Fallopian tube, obtained from post-partum patients (n = 4), converted [3H]-L-arginine to [3H]-L-citrulline (21.0 +/- 8.8 fmol/mg protein/min). This conversion rate was significantly (P < 0.05) reduced in the presence of either EDTA or N-monomethyl-L-arginine monoacetate (L-NMMA), an inhibitor of NOS activity. When bovine (n = 3) ampullary segments were incubated for 36 h in Hanks' balanced salt solution, the concentration of NO2/NO3 in the medium was increased (P < 0.05) if segments were pretreated with lipopolysaccharide (LPS; an inducer of inducible NOS), but not after treatment with LPS + L-NMMA. Additionally, epithelial cells cultured from ampullary segments showed positive staining both for NADPH-diaphorase activity and with antiserum to endothelial NOS. The results of the present study provide direct evidence for the presence of both the Ca(2+)-dependent constitutive form of NOS, as well as the inducible form of NOS activity in human and bovine oviduct. Since the oviduct plays a key role in the reproductive process, it is possible that the two forms of NOS may be involved in the physiological regulation of oviduct function.
Mol Hum Reprod 1996 Aug
PMID:Identification of nitric oxide synthase in human and bovine oviduct. 923 73

Perinatal asphyxia (PA) produces changes in nitric oxide synthase (NOS) activity in neuronal and endothelial cells of the striatum and neocortex. The changes were examined using a histochemical NADPH-diaphorase (NADPH-d) staining method. Newborn rats were exposed to severe PA at 37 degrees C and other groups were subjected to severe PA under hypothermic condition (15 degrees C) for 20 or 100 min, respectively. Quantitative image analysis was performed on the striatum and neocortex in order to count cell number of reactive neurons and to compare the pattern of staining between the different groups of animals. Severe asphyctic pups showed an important neuronal loss in striatum and neocortex that was reduced by hypothermia. NADPH-d(+) neurons with reactive processes were found in the lateral zone of the striatum and neocortex in asphyctic pups. Controls and hypothermic striatum showed rounded cells without reactive process, while no cells were stained in cortex. There was also an increase in NADPH-d activity in endothelial cells in severe asphyctic pups in striatum and neocortex vs control and hypothermically treated animals. Our data evidenced that an inappropriate activation of NOS in neuronal and endothelial cells induced by PA is related to neuronal injury. Hypothermia inhibits neuronal injury and may be a valuable neuroprotective agent.
Mol Chem Neuropathol 1997 Aug
PMID:Short-term changes in NADPH-diaphorase reactivity in rat brain following perinatal asphyxia. Neuroprotective effects of cold treatment. 933 71

In adult male rats, the expression of the neuropeptide galanin and its co-localization with the c-Jun transcription factor and the NADPH-diaphorase, the marker enzyme for the nitric oxide synthase (NOS), was investigated by immunohistochemistry in axotomized neurons following unilateral stereotaxic transection of the (a) mamillo-thalamic tract, (b) medial forebrain bundle, (c) fimbria fornix bundle and (d) sciatic nerve. This surgical procedure resulted in axotomy of neurons of (a) mamillary ncl. (MnM), (b) substantia nigra compacta (SNC) and paraventricular ncl. of thalamic (PF) neurons, (c) medial septum (MS) and vertical diagonal band of Broca (VDB), and (d) sciatic motoneurons and dorsal root ganglia (DRG). In all of these axotomized neuronal subpopulations, expression of c-Jun appeared between 24 and 36 h post-axotomy and persisted on substantial levels for 15 days in the SNC and for 30-50 days in the MnM, PF, MS, VBD, sciatic DRG and motoneurons. Expression of galanin was seen in axotomized MnM, MS and DRG, but not in SNC, PF and sciatic motoneurons. Galanin-immunoreactivity (IR) appeared between 3 and 5 days after nerve fiber transection and persisted up to 50 days in the MnM, MS and DRGs. The cytoplasmic galanin-IR was almost completely restricted to those neurons showing a nuclear c-Jun expression. Moreover, galanin expression showed a long-lasting co-localization with those neurons that exhibited an increased NADPH-diaphorase reactivity in the MnM and DRG or a residual NADPH-diaphorase reactivity in MS post-axotomy. Very similar to galanin, NADPH-diaphorase was not affected by axotomy in the SNC, PF or sciatic motoneurons. Our findings suggest a common mechanism for galanin and NOS (NADPH-diaphorase activity) expression. Since the galanin promotor contains an AP-1 binding site, c-Jun might trigger the lasting induction of galanin in NOS-positive central neurons that survive the axotomy-evoked injury.
Brain Res Mol Brain Res 1997 Aug
PMID:Persisting expression of galanin in axotomized mamillary and septal neurons of adult rats labeled for c-Jun and NADPH-diaphorase. 937 52

Differentiation from replicating slender forms to non-dividing stumpy bloodstream forms of T. brucei limits the parasite population size in the mammalian host in addition to and independently of the antibody response. Using a culture system for pleomorphic strains of T. brucei we show that slender forms very efficiently differentiate to stumpy forms in vitro and that the induction of differentiation is correlated to cell density. Differentiation in the host and in culture were compared using a battery of markers including cell morphology and volume, cell cycle position, the kinetics of the differentiation, expression of NADH dehydrogenase (diaphorase), expression of several differentially regulated transcripts and the kinetics of transformation to replicating procyclic forms after induction with cis-aconitate. By all available criteria, differentiation in culture reflects the natural process in the mammalian host. Time course experiments reveal a very tight temporal correlation between cell cycle arrest of bloodstream forms, appearance of a stumpy differentiation marker and the competence of a bloodstream form population to initiate transformation to procyclic forms in response to cis-aconitate. Our results show that induction of bloodstream form differentiation can occur independently of host-derived cues. We suggest a density sensing mechanism which induces differentiation to the non-dividing stumpy stage and thereby enables the parasite population to autoregulate its proliferation.
Mol Biochem Parasitol 1997 Dec 01
PMID:Cell density triggers slender to stumpy differentiation of Trypanosoma brucei bloodstream forms in culture. 949 48


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