Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:1.6.5.2 (NQO1)
6,196 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

NO synthase (NOS; EC 1.14.23) catalyzes the conversion of L-arginine into L-citrulline and a guanylyl cyclase-activating factor (GAF) that is chemically identical with nitric oxide or a nitric oxide-releasing compound (NO). Similar to the other isozymes of NOS that have been characterized to date, the soluble and Ca2+/calmodulin-regulated type I from rat cerebellum (homodimer of 160-kDa subunits) is dependent on NADPH for catalytic activity. The enzyme also possesses NADPH diaphorase activity in the presence of the electron acceptor nitroblue tetrazolium (NBT). We investigated the requirements of NOS and its content of the proposed additional cofactors tetrahydrobiopterin (H4biopterin) and flavins, further characterized the NADPH diaphorase activity, and quantified the NADPH binding site(s). Purified NOS type I Ca2+/calmodulin-independently bound the [32P]2',3'-dialdehyde analogue of NADPH (dNADPH), which, at near Km concentrations during 3-min incubations was utilized as a substrate and at higher concentrations or after prolonged incubations and cross-linking inhibited NOS activity. The NADPH diaphorase activity was Ca2+/calmodulin-independent, required higher NADPH concentrations than NOS activity, and was affected by dNADPH to a lesser degree. Divalent cations interfered with the diaphorase assay. Per dimer, native NOS contained about 1 mol each of H4biopterin, FAD, and FMN, classifying it as a biopteroflavoprotein, and incorporated 1 mol of dNADPH. No dihydrobiopterin (H2biopterin), biopterin, or riboflavin was detected. These findings suggest that NOS may share cofactors between two identical subunits via high-affinity binding sites.(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:Ca2+/calmodulin-dependent NO synthase type I: a biopteroflavoprotein with Ca2+/calmodulin-independent diaphorase and reductase activities. 137 27

The distribution of nicotinamide adenine dinucleotide phosphate (NADPH)-dependent diaphorase (nitric oxide synthase, NOS) in the endothelial lining of intraparenchymal blood vessels was examined in sections of rat brain prepared from 500 microns thick slices of brain fixed by immersion or from blocks of tissue taken from whole brains fixed by vascular perfusion. In immersion-fixed tissue, a network of stained vessels, many as small as 3 microns in diameter was seen throughout the grey and white matter. In tissue fixed by perfusion small calibre vessels less than 5 microns were less prevalent. The results indicate that NOS is normally present in the endothelial lining throughout the cerebrovascular tree, including the capillaries. Endothelium-derived nitric oxide could have a more widespread role in the regulation of cerebral blood flow than considered previously.
...
PMID:Distribution of nicotinamide adenine dinucleotide phosphate (NADPH)-dependent diaphorase staining in intraparenchymal blood vessels of the rat brain. 750 Dec 35

Using antibodies that react selectively with peptide sequences unique to endothelial nitric oxide synthase (eNOS), we demonstrate localizations to neuronal populations in the brain. In some brain regions, such as the cerebellum and olfactory bulb, eNOS and neuronal NOS (nNOS) occur in the same cell populations, though in differing proportions. In the hippocampus, localizations of the two enzymes are strikingly different, with eNOS more concentrated in hippocampal pyramidal cells than in any other brain area, whereas nNOS is restricted to occasional interneurons. In many brain regions NADPH diaphorase staining reflects NOS catalytic activity. Hippocampal pyramidal cells do not stain for diaphorase with conventional paraformaldehyde fixation but stain robustly with glutaraldehyde fixatives, presumably reflecting eNOS catalytic activity. eNOS in hippocampal pyramidal cells may generate the NO that has been postulated as a retrograde messenger of long-term potentiation.
...
PMID:Endothelial nitric oxide synthase localized to hippocampal pyramidal cells: implications for synaptic plasticity. 751

Nitrogen monoxide (NO) synthase (NOS)-containing neurons (NOSN) were identified by means of reduced nicotinamide adenine dinucleotide phosphate (NADPH) diaphorase histochemistry in nine areas of the human cerebral neocortex from patients 9-74 years of age. Labeled neurons were analyzed according to their disposition in the various layers of the cortical gray and immediately subjacent white matter, and classified according to their cytological features. The vast majority of NOSN (about 80%) are situated in the subcortical white matter and not in the cortical gray proper. Nevertheless, these NOSN extend their processes into the cortical gray and thus appear to participate in intracortical circuits, along with the minority of NOSN situated in all cortical layers. Although many NOSN are small aspiny local circuit neurons, as reported previously, additional distinct cytological types of NADPH diaphorase-positive neurons were also identified, including: (a) local circuit neurons in layer I; (b) granule cells in layer II, and (c) non-pyramidal neurons with densely spinous dendrites in the white matter immediately under the cortical gray. Processes fulfilling light microscopic criteria for axons were seen in many of the above cell types originating from proximal dendrites and, less frequently, from a presumed axon hillock. Taken together, these observations indicate that NOSN belong to several distinct morphological and presumably functional classes, some of which have a unique or restricted laminar location, raising the possibility that some of these various classes of neurons may be selectively affected or spared in neurodegenerative disorders.
...
PMID:Multiple types of nitrogen monoxide synthase-/NADPH diaphorase-containing neurons in the human cerebral neocortex. 752 64

The intramural projections of nerve cells containing serotonin (5-HT), calcitonin gene-related peptide (CGRP), vasoactive intestinal peptide (VIP) and nitric oxide synthase or reduced nicotinamide adenine dinucleotide phosphate diaphorase (NOS/NADPHd) were studied in the ascending colon of 5- to 6-week-old pigs by means of immunocytochemistry and histochemistry in combination with myectomy experiments. In control tissue of untreated animals, positive nerve cells and fibres were common in the myenteric and outer submucous plexus and, except for 5-HT-positive perikarya, immunoreactive cell bodies and fibres were also observed in the inner submucous plexus. VIP- and NOS/NADPHd-positive nerve fibres occurred in the ciruclar muscle layer while VIP was also abundant in nerve fibres of the mucosal layer. 5-HT- and CGRP-positive nerve fibres were virtually absent from the aganglionic nerve networks. In the submucosal layer, numerous paravascular CGRP-immunoreactive (IR) nerve fibres were encountered. Myectomy studies revealed that 5-HT-, CGRP-, VIP- and NOS/NADPHd-positive myenteric neurons all displayed anal projections within the myenteric plexus. In addition, some of the serotonergic myenteric neurons projected anally to the outer submucous plexus, whereas a great number of the VIP-ergic and nitrergic myenteric neurons send their axons towards the circular muscle layer. The possible function of these nerve cells in descending nerve pathways in the porcine colon is discussed in relation to the distribution pattern of their perikarya and processes and some of their morphological characteristics.
...
PMID:Projections of neurochemically specified neurons in the porcine colon. 754 65

The distribution of nitric oxide synthase-immunoreactive (NOS-IR) axons and their relationship to structures immunoreactive to vasoactive intestinal polypeptide (VIP), substance P (SP) and tyrosine hydroxylase (TH) were studied by means of the nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) technique or double-labelling immunofluorescence in the genital organs of cow and pig. Relevant neurons were also investigated in the pig. NOS-containing neural structures were TH-immunonegative in bovine or porcine genital organs, or in the studied ganglia. In the bovine ovary, NOS-IR nerves were neither VIP-IR nor SP-IR, whereas in the pig, most NOS-containing axons were also VIP-IR. The oviduct was supplied by single NOS/VIP- or NOS/SP-containing nerves, whereas in the uterus, NOS-IR axons were moderate in number, often being immunoreactive for VIP or SP. Numerous NOS/VIP-IR and NOS/SP-IR nerves were found in the vagina of both species. In all tissues studied, NOS-IR axons were mainly related to vascular smooth muscle. Most of the neurons of the paracervical ganglia and some neurons in dorsal root ganglia exhibited strong NOS activity. Only single neurons in sympathetic ganglia were NADPH-d-positive. Most nitrergic neurons in the autonomic ganglia were VIP-IR but SP-immunonegative. The sensory neurons were mostly NOS/SP-IR, whereas only single neurons co-expressed NOS and VIP immunoreactivity.
...
PMID:The distribution and co-localization of immunoreactivity to nitric oxide synthase, vasoactive intestinal polypeptide and substance P within nerve fibres supplying bovine and porcine female genital organs. 755 66

Using acetylcholinesterase (AChE), nicotinamide adenine dinucleotide diaphorase (NADHd), and nicotinamide adenine dinucleotide phosphate diaphorase (NADPHd) enzyme histochemical techniques, the ganglionated plexuses of the porcine enteric nervous system were investigated in small intestine whole-mount preparations. Both AchE and NADHd techniques revealed a majority of the neurons in the ganglia of all three major plexuses. The AchE technique also demonstrated clearly the axodendritic networks of the plexus myentericus. Intraganglionic blank areas revealed the localization of negative cell groups. A very high correlation was found between the activity of both enzymes in one neuron, although this correlation was certainly not linear. Many neurons exhibited a stronger signal for one enzyme. A very small part of the positive nerve cells showed intense staining for both AchE and NADHd. The NADPHd technique demonstrated that the NADPHd-positive neurons fill the negative intraganglionic spaces in the ganglia. Double staining with the two other enzymes showed virtually no colocalization of NADPHd with either NADHd or AchE in the porcine jejunal enteric ganglia. Little negative intraganglionic spaces were seldom found, leaving room for perhaps still more negative enteric neurons. Based upon these results we suggest that the enteric neurons of the porcine small intestine can be subdivided into AchE-NADHd and NADPHd subpopulations. Since the latter colocalizes with the neuronal NO synthase enzyme, we further suggest a subdivision of the enteric nerve cells into AchE-NADHd and NOS-NADHd neurons.
...
PMID:Classification of the enteric nerve cells of the porcine small intestine into two subpopulations using enzyme histochemical techniques. 781 33

The nasal mucosa plays an important role in defense of the lung against harmful agents. It has been suggested that this is partly mediated by the production of nitric oxide (NO). We have investigated the localization of the messenger ribonucleic acids (MRNAs) for human endothelial NO synthase (Type III NOS) and inducible NO synthase (Type II NOS) and the immunoreactivities of these enzymes in human nasal mucosa by immunohistochemistry, in situ hybridization, and reduced nicotinamide adenine diphosphate (NADPH) diaphorase histochemistry. Inferior nasal turbinates were obtained from 27 patients at the time of surgery for local disease. Strong immunostaining for Type III NOS was localized to vascular endothelium, surface epithelium, and submucosal glands in all subjects. Moderate immunostaining for Type II NOS was seen in surface epithelium; glandular, inflammatory, and vascular endothelial cells; and smooth-muscle cells in the specimens from patients with chronic rhinitis only. In situ hybridization showed expression of the mRNA for Type III NOS in similar sites to those shown by immunohistochemistry, whereas the mRNA for Type II NOS was predominantly localized to inflammatory cells. The sites of NOS expression were further confirmed by NADPH histochemical staining. These findings demonstrate the cellular expression of NOS in the human nasal mucosa and suggest a possible role for Types II and III NO synthase in the regulation of blood flow, nasal secretion, and ciliary movement in health and disease.
...
PMID:Expression of nitric oxide synthase in the human nasal mucosa. 856 42

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

Previous studies have shown the association of NOS I with the sarcolemma in mammalian striated muscle fibers, implicating the dystrophin complex (DC) as a major anchor for the enzyme. The potential role of the sarcoglycan subcomplex, especially of alpha-sarcoglycan (adhalin), as part of the DC in holding of NOS I in the sarcolemmal position was examined by carrying out a comparative study on the distribution of NOS I, dystrophin, dystrophin-associated glycoproteins (DAG) and alpha-sarcoglycan in various skeletal muscles of non-mammals. Rat muscles were included since they reflect the situation in mammals. Catalytic NOS-associated diaphorase (NOSaD) activity as well as NOS I and DAG immunoreactivities were positive in the saracolemma region of skeletal muscle fibers of rats, chicken, and turtles. Adhalin immunoreactivity was present in the rat but absent in the chicken and turtle muscle surface membrane. These data suggest that alpha-sarcoglycan and therefore the entire sarcoglycan subcomplex may not be needed for localizing NOS I to the sarcolemma in these non-mammalian species. This may hold for skeletal muscle fibers in general.
...
PMID:Adhalin (alpha-sarcoglycan) is not required for anchoring of nitric oxide synthase I (NOS I) to the sarcolemma in non-mammalian skeletal (striated) muscle fibers. 886 63


1 2 3 4 5 6 7 8 Next >>

---