Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.6.99.3 (diaphorase)
 5,903 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An antibody to cytochrome P450 oxidoreductase, purified from rat liver, has been used for the immunohistochemical localization of cytochrome P450 oxidoreductase-like immunoreactivity in the rat central nervous system. The distribution of this immunoreactivity has been confirmed using in situ hybridization with specific cytochrome P450 oxidoreductase antisense DNA probes. Cytochrome P450 oxidoreductase immunoreactivity was detected in neurons and was found in some glial populations. Immunoreactivity and in situ messenger RNA signals were present in many forebrain areas including the olfactory bulb, in the cerebral cortex, caudate-putamen, globus pallidus, hypothalamus, thalamus and hippocampus. Cytochrome P450 oxidoreductase was also detected in the nucleus of the posterior commissure, superior colliculus, intermediate gray layer, periaqueductal gray and in the molecular, Purkinje and granular layers of the cerebellum. In the brain stem, cytochrome P450 oxidoreductase was detected in the substantia nigra, nucleus locus coeruleus and raphe nucleus. Western blotting studies revealed the brain immunoreactive protein has a mol. wt of approximately 72,000, as reported for cytochrome P450 oxidoreductase purified from rat brain microsomes. The distribution of cytochrome P450 oxidoreductase immunoreactivity was compared with the distribution of cells exhibiting NADPH diaphorase activity, which has been established as a histochemical marker for neuronal nitric oxide synthase, an enzyme which has a C-terminus with some structural similarity with cytochrome P450 oxidoreductase and catalyses a complex reaction resulting in the synthesis of nitric oxide from arginine. In general, cytochrome P450 oxidoreductase immunoreactivity and nitric oxide synthase diaphorase activity did not co-localize; however, some neuronal populations did express nitric oxide synthase and exhibit cytochrome P450 oxidoreductase immunoreactivity. Results of immunohistochemistry and in situ hybridization experiments suggest cytochrome P450 oxidoreductase is widespread in the rat central nervous system. The distribution pattern of cytochrome P450 oxidoreductase did not match with those of any one neurotransmitter; however, it did coincide with some brain regions known to harbour central catecholaminergic neurons. The general distribution of cytochrome P450 oxidoreductase was similar to the distribution reported for haeme oxygenase 2 and several cytochrome P450 enzymes. It is possible that malfunctions in cytochrome P450 enzyme systems and/or the haeme oxygenase 2 pathways, both of which involve cytochrome P450 oxidoreductase, may have implications in neurodegenerative diseases.
 ...
PMID:Localization of NADPH cytochrome P450 oxidoreductase in rat brain by immunohistochemistry and in situ hybridization and a comparison with the distribution of neuronal NADPH-diaphorase staining. 796 13

The 'nicotinamide adenine dinucleotide phosphate diaphorase' histochemical technique was used as a marker of neuronal nitric oxide synthase to assess the presence of the enzyme in the anterior hypothalamus of the rat. Particular attention was focused on the subparaventricular zone, periventricular area and suprachiasmatic nucleus. The results show that there is strong staining in the anterior hypothalamus particularly in the subparaventricular zone by the perinuclear regions of the suprachiasmatic nucleus, and in the periventricular nucleus. Some diaphorase activity was also seen within the suprachiasmatic nucleus, but this was much weaker than in the surrounding areas. These results, taken together with existing evidence, would further suggest the involvement of nitric oxide in the signal transduction pathway in the suprachiasmatic nucleus.
 ...
PMID:NADPH diaphorase activity around the suprachiasmatic nucleus in rat brain. 859 63

The role of nitric oxide or related molecules as neuromodulators was investigated in the buccal and the abdominal ganglia of the mollusc Aplysia californica. In a first step we showed that reduced nicotinamide adenine dinucleotide phosphate-diaphorase histochemistry and specific nitric oxide synthase immunohistochemistry labelled the same neurons and fibres in both ganglia, pointing to the presence of a neuronal nitric oxide synthase. In a second step, we performed voltammetric detection of nitric oxide-related molecules using a microcarbon electrode in a reduction mode. A peak identified as N-nitroso-L-arginine was detected at -1.66 V in both ganglia. The identification of this compound as a product of endogenous nitric oxide synthase activity was reinforced by the fact that its peak amplitude was decreased in the presence of NG-monomethyl-L-arginine, an inhibitor of nitric oxide synthase, and increased with its substrate, L-arginine. An additional proof of a nitric oxide synthase activity was the detection of nitrites and nitrates in high concentrations (millimolar range) by capillary electrophoresis. We also showed that these nitric oxide-related molecules modulated acetylcholine release at two identified synapses in these ganglia. L-Arginine decreased acetylcholine release at the inhibitory synapse (buccal ganglion), whereas it increased acetylcholine release at the excitatory synapse (abdominal ganglion). The nitric oxide synthase inhibitors, N omega-nitro-L-arginine and NG-monomethyl-L-arginine, had opposite effects. Moreover, the exogenous nitric oxide donor, 3-morpholinosydnonimine hydrochloride mimicked the effects of L-arginine on both inhibitory and excitatory cholinergic synapses. The identification of two cholinergic synapses where nitric oxide affects acetylcholine release in opposite ways provides a useful tool to study the cellular mechanisms through which nitric oxide-related molecules modulate transmitter release.
 ...
PMID:A nitric oxide synthase activity is involved in the modulation of acetylcholine release in Aplysia ganglion neurons: a histological, voltammetric and electrophysiological study. 859 65

Nitric oxide synthase (EC 1.14.13.39) binds arginine and NADPH as substrates, and FAD, FMN, tetrahydrobiopterin, haem and calmodulin as cofactors. The protein consists of a central calmodulin-binding sequence flanked on the N-terminal side by a haem-binding region, analogous to cytochrome P-450, and on the C-terminal side by a region homologous with NADPH:cytochrome P-450 reductase. The structure of recombinant rat brain nitric oxide synthase was analysed by limited proteolyis. The products were identified by using antibodies to defined sequences, and by N-terminal sequencing. Low concentrations of trypsin produced three fragments, similar to those in a previous report [Sheta, McMillan and Masters (1994) J. Biol. Chem. 269, 15147-15153]: that of Mr approx. 135000 (N-terminus Gly-221) resulted from loss of the N-terminal extension (residues 1-220) unique to neuronal nitric oxide synthase. The fragments of Mr 90000 (haem region) and 80000 (reductase region, N-terminus Ala-728) were produced by cleavage within the calmodulin-binding region. With more extensive trypsin treatment, these species were shown to be transient, and three smaller, highly stable fragments of Mr 14000 (N-terminus Leu-744 within the calmodulin region), 60000 (N-terminus Gly-221) and 63000 (N-terminus Lys-856 within the FMN domain) were formed. The species of Mr approx. 60000 represents a domain retaining haem and nitroarginine binding. The two species of Mr 63000 and 14000 remain associated as a complex. This complex retains cytochrome c reductase activity, and thus is the complete reductase region, yet cleaved at Lys-856. This cleavage occurs within a sequence insertion relative to the FMN domain present in inducible nitric oxide synthase. Prolonged proteolysis treatment led to the production of a protein of Mr approx. 53000 (N-terminus Ala-953), corresponding to a cleavage between the FMN and FAD domains. The major products after chymotryptic digestion were similar to those with trypsin, although the pathway of intermediates differed. The haem domain was smaller, starting at residue 275, yet still retained the arginine binding site. These data have allowed us to identify stable domains representing both the arginine/haem-binding and the reductase regions.
 ...
PMID:Identification of the domains of neuronal nitric oxide synthase by limited proteolysis. 866 Mar 10

The purpose of this study was to determine whether immobilization stress can cause changes in the enzyme activity and gene expression of neuronal nitric oxide synthase (nNOS) in the hypothalamus, pituitary, and adrenal gland in rats. NOS enzyme activity was measured as the rate of [3H]arginine conversion to citrulline, and the level of nNOS mRNA signal was determined using in situ hybridization and image analysis. NOS-positive cells were also visualized using nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-diaphorase) histochemistry and by immunohistochemistry using an anti-nNOS antibody. A significant increase of NOS enzyme activity in the anterior pituitary, adrenal cortex, and adrenal medulla (1.5-, 3.5-, and 2.5-fold) was observed in the stressed animals (immobilization of 6 h) as compared to non-stressed control rats. Up-regulation of nNOS mRNA expression in anterior pituitary and adrenal cortex was already detectable after stress for 2 h with 1.5- and 2-fold increase, respectively. The nNOS mRNA signals in hypothalamic paraventricular nucleus (PVN) significantly increased after the stress for 6 h. This increase in NOS enzyme activity was confirmed using NADPH-diaphorase staining and immunostaining in the PVN and adrenal cortex. An increase of NOS enzyme activity in adrenal medulla after immobilization for 6 h posited by far longer than in the adrenal cortex and anterior pituitary. The present findings suggest that psychological and/or physiological stress causes NO release in hypothalamic-pituitary-adrenal (HPA) axis and in sympatho-adrenal system. It is suggested that NO may modulate a stress-induced activation of the HPA axis and the sympatho-adrenal medullary system. The different duration of stress-induced NOS activity in HPA axis and the adrenal medulla may suggest NO synthesis is controlled by separate mechanism in the two HPA and the sympatho-adrenal systems.
 ...
PMID:Immobilization-induced stress activates neuronal nitric oxide synthase (nNOS) mRNA and protein in hypothalamic-pituitary-adrenal axis in rats. 878 9

Protoporphyrin IX inhibits citrulline formation by all three nitric oxide synthase isoforms in a manner reversible by dilution. Zinc protoporphyrin IX, by contrast, produces a time- and concentration-dependent inactivation of all three nitric oxide synthase isoforms, not reversible by dilution. The inhibition of citrulline formation by protoporphyrin IX occurs with IC50 values of 0.8, 4, and 5 microM for the nNOS, iNOS, and eNOS isoforms, respectively. Inhibition by N-methyl-protoporphyrin IX occurs at IC50 values of 6, 5, and 8 microM for the nNOS, iNOS, and eNOS isoforms, respectively. Inhibition of nitric oxide synthase by protoporphyrin IX is a multisite, positively cooperative inhibition that exhibits a Hill coefficient of 2.3 for the iNOS isoform. Protoporphyrin IX reduces the maximal velocity of citrulline formation for both the iNOS and nNOS isoforms without altering the K(m) for the arginine substrate or the EC50 value for the tetrahydrobiopterin cofactor. Protoporphyrin IX inhibits the arginine-independent NADPH oxidase activity of nNOS with an IC50 value of 1 microM but has no effect on cytochrome c reductase activity at concentrations as high as 30 microM. At concentrations of 10 and 20 microM, protoporphyrin IX inhibits NO formation by cytokine-induced murine RAW 264.7 cells; however, these inhibitions are accompanied by significant cellular cytotoxicity. Coproporphyrins I and III, uroporphyrins I and III, and porphobilinogen, intermediates in the biosynthesis of heme that accumulate in hepatic porphyrias, are ineffective as inhibitors of the nitric oxide synthase isoforms. Since protoporphyrin IX is the immediate biosynthetic precursor of heme that accumulates in hepatic protoporphyria, iron deficiency anemia, and lead poisoning, protoporphyrin IX inhibition of nitric oxide synthase may contribute to the pathophysiology of these conditions.
 ...
PMID:Inhibition of nitric oxide synthase isoforms by porphyrins. 880 50

The changes of neuronal nitric oxide synthase (nNOS) mRNA expression in the rat adrenal gland following immobilization-induced stress were examined by the in situ hybridization technique. To introduce immobilization stress, the animals were wrapped with flexible wire gauze for 6 h. In the adrenal medulla and cortex, signals for nNOS mRNA were detected. In the adrenal medulla, the difference between non-stressed and stressed animals was not clear. In the adrenal cortex, the expression of nNOS mRNA markedly increased (2.5-fold) in the stressed animals. Nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-diaphorase) histochemistry also showed an increase of staining in adrenal cortex after stress. This suggests that nitric oxide (NO) is involved in stress-induced activation in adrenal cortex function.
 ...
PMID:Marked increases in neuronal nitric oxide synthase (nNOS) mRNA and NADPH-diaphorase histostaining in adrenal cortex after immobilization stress in rats. 881 27

In the rat spinal cord, we found substantial co-existence of fibroblast growth factor-2, fibroblast growth factor receptor (type-1 or flg) immunoreactivity and reduced nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase activity (a histochemical marker for neuronal nitric oxide synthase) in preganglionic autonomic cell groups of intermediate layers VI, VII and X. Anti-fibroblast growth factor-2 and anti-nitric oxide synthase binding sites were confined to the cytoplasm of reactive neurons as judged by immunogold electron microscopy. Within the major autonomic nucleus, i.e. intermediolateral column, three different populations were identified: (i) fibroblast growth factor and fibroblast growth factor receptor, (ii) fibroblast growth factor/NADPH-diaphorase and (iii) NADPH-diaphorase-only stained cell groups. Sympathoadrenal neurons were prelabelled with fluorescent tracer Fast Blue and co-stained for fibroblast growth factor-like protein and NADPH-diaphorase, suggesting heterologous diversification of neuronal phenotypes and functional organization in the spinal autonomic system. Our findings suggest intriguing roles for nitric oxide and fibroblast growth factor-2 cytokine in the preganglionic sympathetic spinal cord system: The "short-term" diffusible messenger nitric oxide may act as "tonic" and/or "phasic" signal within rostrocaudally oriented function-specific preganglionic units necessary for integrated target control. The "long-term" messenger fibroblast growth factor-2 may be involved in, for example, cytokine-dependent regulation of neuronal NADPH-diaphorase/nitric oxide synthase. Furthermore, co-existence of NADPH-diaphorase, fibroblast growth factor-2 and receptor in sympathoadrenal neurons suggest mutual target-specific regulatory functions, e.g. hormone release and blood perfusion or maintenance of phenotype and plasticity responsiveness of adrenal medullary tissue.
 ...
PMID:Co-existence of NADPH-diaphorase, fibroblast growth factor-2 and fibroblast growth factor receptor in spinal autonomic system suggests target-specific actions. 884 11

The ultrastructural localization of nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d), which has been considered to be a neuronal nitric oxide synthase (NOS), was explored in the vascular endothelial cells and perivascular nerves of the cerebral arteries in the rat. In order to detect NADPH-d activity, 2-(2'-benzothiazolyl)-5-styryl-3-4-(4'-phthalhydrazidyl) tetrazolium chloride was utilized as a substrate for NADPH-d histochemistry at the electron microscopic level. In vascular endothelial cells, NADPH-d positive deposits were observed on the nuclear envelope and the endoplasmic reticulum (smooth or rough surfaced). Positive deposits were seen on distinct membrane portions of the endoplasmic recticulum (ER) in the perivascular nerves (axons), but no positive materials were observed either in the cytoplasm of the endothelial cells or in the axoplasm of the perivascular nerves. It was concluded that NOS is located on the membranes of the ER and the nuclear envelope, and that NOS may play substantial roles in the regulation of the cerebral vessels.
 ...
PMID:The ultrastructural localization of NADPH-diaphorase in the cerebral arteries of rats. 902 50

The distribution of nicotinamide adenine dinucleotide phosphate diaphorase (NADPHd) reactivity and neuronal nitric oxide synthase immunoreactivity (nNOS-IR) was investigated in the rat retina during photoreceptor regeneration. Photoreceptor damage and the disappearance of a NADPHd reactive/nNOS-IR band corresponding to inner photoreceptor segments were observed after continuous exposure to light irradiation. Both events were reversible after 20 days of total darkness. Also a progressive decrease in the number and in the staining intensity of NADPHd reactivity in amacrine cells were found along the first 3-6 days of darkness stabilizing thereafter in both illuminated and control groups. However, staining intensity in the former group remained more elevated than in the latter one. NOS activity in the retina varies depending on functional and pathological states.
 ...
PMID:Changes in NADPH diaphorase reactivity and neuronal nitric oxide synthase in the rat retina following constant illumination. 928 Jan 64


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>