Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.5.1.19 (NOS)
 7,285 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The ultrastructural distribution of nitric oxide synthase (neuronal isoform, type I) and endothelin immunoreactivity was examined in the developing and ageing male Wistar rat pulmonary artery and vein. This study demonstrates that from birth to old age (24 months) nitric oxide synthase and endothelin are localized within subpopulations of endothelial cells in the pulmonary vasculature. In the pulmonary artery and vein of newborn rats, and pulmonary vein of 24-month-old rats, positive labelling for nitric oxide synthase was also observed in the vascular smooth muscle. During development and ageing there were ultrastructural and immunocytochemical alterations in the intima of the pulmonary artery and vein. In older animals, damaged endothelial cells were seen alongside healthy-appearing cells, rich in cytoplasmic vesicles and endoplasmic reticulum. In contrast to damaged cells, the healthy-appearing endothelial cells displayed positive cytoplasmic labelling for nitric oxide synthase or endothelin. These immunopositive cells also appeared in the altered regions of the vessels where substantial enlargement of subendothelial extracellular matrix and the presence of various forms of degenerating macrophages and large bundles of collagen fibres were evident. Damage to the pulmonary artery was particularly evident at the ages of 12 and 24 months; various forms of macrophages, some of which displayed positive labelling for nitric oxide synthase and endothelin, were present in the altered intimal subendothelial zone. In conclusion, this study on the pulmonary vasculature suggests that endothelin and NOS in endothelial cells play a role in the local control of vascular tone throughout the lifespan of rats, even in older animals when there is intimal thickening and some endothelial damage. NOS and endothelin was also seen in smooth muscle and macrophages at certain stages in postnatal development and ageing.
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PMID:Ultrastructural localization of nitric oxide synthase and endothelin in rat pulmonary artery and vein during postnatal development and ageing. 859 65

Because the role of intracellular Ca2+ in the two-signal process for the induction of nitric oxide (NO) synthesis is controversial, this study was undertaken to examine the role of Ca2+ in the transcriptional regulation of inducible NO synthase (iNOS) in murine peritoneal macrophages. Treatment of the cells with thapsigargin (TG) or 2,5-di-(t-butyl)-1,4-benzodihydroquinone (tBuBHQ), which are the specific and potent Ca(2+)-ATPase inhibitors of endoplasmic reticulum (ER), showed modest effects on tumoricidal function, whereas TG or tBuBHQ in combination with interferon-gamma (IFN-gamma) or lipopolysaccharide (LPS) showed marked effects on tumoricidal function of the cells. The tumoricidal effects of the activated macrophages were correlated with the amount of NO synthesis, and totally abrogated by the use of NOS inhibitor, NG-monomethyl-L-arginine (NGMMA). The increases in NO synthesis was reflected as increased amounts of iNOS mRNA by Northern blotting. To confirm that iNOS induction was due to the changes in the intracellular Ca2+ level, the acetoxymethyl ester of 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA-AM), an intracellular Ca2+ chelator, was used. Blocking the increase of cytosolic free Ca2+ significantly decreased the induction of NO synthesis. To demonstrate that intracellular Ca2+ acts as a 'priming' signal rather than a 'triggering' signal on the induction of NO synthesis by murine peritoneal macrophages, we designed several experiments. When the cells were treated with TG 6 hr after the treatment with IFN-gamma, there was no increase in NO synthesis. In addition, when the cells were treated with TG or LPS 6 hr after treatment with tBuBHQ, a synergistic increase on NO synthesis was shown only in the case of LPS. When phorbol 12-myristate 13-acetate (PMA), a protein kinase C (PKC) activator, was added to the cells 6 hr after the treatment with TG, there was a marked co-operative induction of NO synthesis, even though PMA alone has no effect. Based on the results obtained in this study, we suggest that cytosolic Ca2+ might be enough for the expression of iNOS gene as a priming signal and PKC might be involved in the induction of NO synthesis as a triggering signal by post-transcriptional modification of iNOS mRNA or iNOS itself in the activated murine peritoneal macrophages.
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PMID:Role of intracellular calcium as a priming signal for the induction of nitric oxide synthesis in murine peritoneal macrophages. 869 94

The subcellular localization of neuronal nitric oxide (NO) synthase (NOS)-immunoreactive (NOSir) elements in the brain of the Atlantic salmon was investigated by means of electron microscopy and confocal laser scanning microscopy. NOSir structures are present only in neuronal elements. In neuronal processes, strong NOS immunoreactivity was mainly localized within synaptic vesicles or seen as a dense accumulation associated with the plasma membrane of dendrites and at terminal formations. NOSir precipitate was also associated with microtubuli and mitochondrial outer membranes. The highest accumulation of NOS immunoreactivity was found in dendrites located in close apposition to immunonegative myelinated or unmyelinated neural processes. Several NOSir and unmyelinated immunonegative profiles formed synaptic specializations. Immunonegative neurons in contact with NOSir processes always contained round clear synaptic vesicles. In neuronal somata, strong NOS immunoreactivity was localized in the cristae of some large mitochondria, whereas vacuoles and the endoplasmic reticulum showed a relatively weak staining. Confocal microscopic analysis of NOS immunofluorescence showed a corresponding subcellular localization of NOS in different brain regions, but also indicated the presence of NOS axosomatic terminals. Our data show that specific neurons contain a neuronal NOS-like molecule which to a high degree is stored in vesicles and is accumulated at various sites along the neuronal processes or at specific synaptic terminal formations. Thus, NO may be formed and exert its action at various sites along the processes of NOS-synthesizing neurons. The present study provides evidence at the ultrastructural level that NO may play a messenger role in neural circuits involved in visual and hypophysiotrophic brain functions.
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PMID:Subcellular localization of neuronal nitric oxide synthase in the brain of a teleost; an immunoelectron and confocal microscopical study. 903 95

The NOS-related NADPH-diaphorase activity was studied by transmission electron microscopy in the peritubular myoid cells and fibroblasts of normal mouse testis. The reaction product was observed on the membranes of the endoplasmic reticulum, on the Golgi apparatus and nuclear envelope. The peritubular myoid cells and fibroblasts showed similar ultracytochemical features; the intensity of the enzymatic reaction was suggestive of an important role of the NOS/cGMP enzymatic system in these cells. Some hypotheses on the role of NO in the peritubular myoid cells and fibroblasts are proposed.
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PMID:Ultrastructural demonstration of the NADPH-diaphorase activity in peritubular myoid cells and fibroblasts of the lamina propria of the mouse seminiferous tubules. 929 98

1. Blood vessel tone is determined both by smooth muscle and endothelial functions. In coronary arteries taken from rat (Fisher-Lewis) cardiac transplanted hearts, the inducible form of NOS (iNOS) in smooth muscle is more active, while acetylcholine-induced nitric oxide production in the endothelium is greatly diminished. This causes a greatly reduced myogenic constriction, in pressurized septal arteries taken from immunologically challenged transplanted hearts. 2. The sarcoplasmic reticulum (SR) of smooth muscle and the endoplasmic reticulum (ER) of endothelial cells sequester Ca2+ from the cytoplasm. This reduces the intracellular concentration of free Ca2+, which is necessary for the activation of cellular processes. The release of Ca2+ from internal stores occurs through ryanodine and IP3 recoptors located on the SR membrane. 3. The superficial SR/ER also interacts with ion exchangers and pumps in the plasma membrane. This allows for the superficial SR/ER to function in Ca2+ extrusion; for example, inhibition of the SR/ER Ca(2+)-ATPase (SERCA) partially inhibits the rate of loss Ca2+ from the cell. Recent data suggest that the SR Ca(2+)-ATPase and the Na(+)-Ca2+ exchanger of smooth muscle cells function in series; that is, Ca2+ uptake by the SR followed by release towards the exchanger to mediate extrusion. This interaction between the SERCA of the superficial SR and ion exchangers and pumps creates intracellular Ca2+ gradients. 4. The SERCA of the superficial, peripherally distributed SR/ER also serves to regulate Ca2+ entry from the extracellular space. This occurs in part by inhibition of the superficial buffer barrier function of the SR as well as by depletion of stimulated Ca2+ entry. 5. Ca2+ entry is also regulated in endothelial and smooth muscle cells by the membrane potential. Membrane hyperpolarization increases the driving force for Ca2+ entry into endothelial cells, which lack voltage-gated Ca2+ channels, and reduces open state probability of voltage-gated Ca2+ channels in vascular smooth muscle cells. The two cell types have electrical contact and interact in a dynamic manner to regulate blood vessel diameter.
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PMID:Endothelium-smooth muscle interactions in blood vessels. 940 74

Intracellular Ca2+ concentration ([Ca2+]i) was measured by Fura 2/AM fluorescence imaging microscopy in freshly isolated valvular endothelial cells taken from female and male rats. The basal level of [Ca2+]i was significantly elevated in female valvular endothelial cells when compared to males (P < 0.05). Inhibition of the sarco-endoplasmic reticulum Ca(2+)-ATPase with cyclopiazonic acid (CPA, 10 microM) caused a greater increase in the [Ca2+]i in female than male endothelial cells. Removal of extracellular Ca2+ returned the [Ca2+]i to the basal level. The rate of [Ca2+]i decline was significantly slower in female endothelial cells compared to males. There were no differences in the unstimulated rate of Mn2+ quenching between two groups. These results demonstrate that estrogen affects NOS at least in part, by an alteration in Ca2+ homeostasis in endothelial cells.
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PMID:Gender difference in the basal intracellular Ca2+ concentration in rat valvular endothelial cells. 970 27

On the basis of our own experimental data and analysis of data from the literature the existence of nitric oxide cycle in mammals is substantiated. Two components underlie the nitric oxide cycle: 1) the reaction catalyzed by NO-synthases (constitutive, inducible, and endothelial--NOS-I, -II, and -III); and 2) the nitrite-reductase reactions catalyzed by electron-donor systems with the participation of NADH, NADPH, flavoproteins, and heme-containing proteins. In mammalian cells NO is enzymatically formed from terminal guanidine nitrogen of L-arginine by a family of at least three distinct NOS isoenzymes. As a result of nonenzymatic/enzymatic NO oxidation, NO2- and NO3- ions are formed: L-Arg --> NO --> NO2-/NO3-. The reduction of NO2- ions to NO occurs via the nitrite-reductasereaction: NO2- + e- --> NO. The reduction of NO2- ions to NO is realized by electron-donor systems with the participation of NADH, NADPH, flavoproteins, and cytochrome oxidase in mitochondria and by NADH, NADPH, flavoproteins, and cytochrome P-450 in endoplasmic reticulum. In erythrocytes the reduction of NO2- ions to NO is catalyzed by electron-donor systems with participation of NADH, NADPH, flavoproteins, and deoxy-hemoglobin. The role of ascorbic acid and reduced glutathione should be noted among low-molecular-weight compounds. Thus, the presence of the nitric oxide cycle provides the cyclic transformation as follows: L-arginine --> NO --> NO2-/NO3- --> NO.
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PMID:NO-synthase and nitrite-reductase components of nitric oxide cycle. 972 40

The effects of the chronic ethanol treatment on the NOS-related NADPH-diaphorase activity were described in the mouse Leydig cells by means of transmission electron microscope. The recovery of the Leydig cells was also examined during a period of four weeks. About 10% of the Leydig cells showed various degrees of morphological alterations, consisting in increased number of lipid droplets, rarefaction and vacuolization of the cytoplasmic matrix. Other groups of Leydig cells (about 10%) revealed evident signs of degeneration. The NADPH-d activity was reduced both in apparently normal and injured Leydig cells and a moderate enzymatic reaction was only detected in the smooth endoplasmic reticulum. A week after the treatment an increased number of the degenerating Leydig cells and a further reduction of the enzymatic reaction were observed. Then, the Leydig cells showed a progressive recovery and four weeks after the treatment they exhibited a normal morphology and NADPH-d enzymatic reaction. These results demonstrated for the first time the inhibition of NOS activity in the Leydig cells after chronic ethanol administration.
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PMID:The ultrastructural localization of NADPH-diaphorase enzymatic activity in the Leydig cells of mouse. effects of ethanol administration. 1131 46

A modified cry1Ac gene was generated by fusing with Lys-Asp-Glu-Lue (KDEL), an endoplasmic reticulum retention signal at the 3'-ends, with signal peptide coding sequence of Soybean kunitz trypsin inhibitor (SKTI) at the 5'-ends. Vector containing the modified cry1Ac gene coding region flanked by the corn ubiquitin 1 promoter and the nopaline synthase gene (nos) terminator with Hygromycin Phosphotransferase (hpt) gene as a plant selection marker was constructed. The modified cry1Ac gene in which toxic protein targeted to endoplasmic retention was successfully transferred into Minghui 81 (Oryza sativa L. subsp. indica), an elite restoring line of commercial CMS indica hybrid rice, through particle bombardment and obtained fertile transformants. Homozygous transgenic rice lines were obtained in the third generation exploiting self-seed set reproduction and HygromycinB selection. These transgenic lines were confirmed with polymerase chain reaction (PCR) amplification, Southern blotting and ELISA detection. Pest insect-resistant bioassay indicated that some of the homozygous cry1Ac-transgenic rice plants of T2 progeny showed high-level resistance against striped stem borer (Chilo suppressalis) at field trials.
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PMID:[Obtaining stem borer-resistant homozygous transgenic lines of Minghui 81 harboring novel cry1Ac gene via particle bombardment]. 1209 30

NADPH-diaphorase is a useful technique to reveal NO producing neurons at light microscopic level (LM). A modification of the technique using the tetrazolium salt BSPT as substrate, is useful to study the ultrastructure of NO neurons. The aim of this work was to perform a detailed analysis of NADPH-diaphorase reactive neurons in rat mesencephalon both at light and electron microscopic levels. NADPH-diaphorase reactive neurons were observed in superior colliculus, in central gray matter, in dorsal and medial raphe and in the pedunculopontine tegmental nucleus using two histochemical techniques at LM. Electron microscopy showed deposits on membranes of the endoplasmic reticulum, Golgi apparatus and nuclear envelope of dorsal raphe neurons. Presynaptic and postsynaptic terminals showed deposits on membranous elements but postsynaptic terminals also showed deposits on the inner surface of their membranes. Further physiological studies are needed to clarify the meaning of the ultrastructural findings such as the putative interaction of NOS with postsynaptic proteins, receptors or membranous channels.
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PMID:Distribution of NADPH-diaphorase in rat mesencephalon: a light and electron microscopical study. 1224 May 59


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