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

The carotid body plays an important role in ventilatory adaptation during chronic hypoxia. Nitric oxide (NO) may act as a regulator in neurotransmission, influencing the carotid body chemosensory discharge. The aim of the study was to understand if NO could contribute to the adaptation process during chronic hypoxia. The rats were kept in chronic hypoxia (10-11% inspired oxygen) for 12 days, while the controls were kept in room air (21% O2). The distribution for diaphorase activity and immunohistochemistry for nitric oxide synthase (NOS) showed that chronic hypoxia induces an increase in NOS activity in the carotid body. It was concluded that NO release increased during chronic hypoxia and causes an inhibitory effect on carotid chemosensory discharge of the rat carotid body.
Comp Biochem Physiol A Mol Integr Physiol 1998 Jun
PMID:Does chronic hypoxia increase rat carotid body nitric oxide? 977 3

Nitric oxide (NO) is an important modulator of contractile activity in various tissues. The aim of the present study was to investigate the possible existence of an NO system within the human uterine cervix and to study the effects of NO on the cervix in early pregnancy. Cervical tissue specimens were obtained from 24 women in connection with first trimester legal abortion. NADPH diaphorase staining was used to identify nitric oxide synthase activity within the cervical tissue. Cylindrical tissue specimens were mounted in organ bath chambers for isometric registration of contractile activity. The presence of a functional NO system in the cervix was investigated by adding either sodium nitroprusside or spermine NONOate, two different NO donors, or 8-bromo cGMP, an analogue of the second messenger cyclic guanosine monophosphate (cGMP), to the organ baths. Positive NADPH diaphorase staining was clearly observed in the walls of blood vessels, in cervical smooth muscle cells, and cells scattered in the connective tissue. The NO donating drugs sodium nitroprusside and spermine NONOate both caused a dose-dependent inhibition of spontaneous contractile activity with significant inhibition at concentrations of 10(-5) and 10(-7) M respectively. Furthermore, the participation of NO in the regulation of cervical contractility was indicated by a significant concentration-dependent inhibition of spontaneous contractions when 8-bromo cGMP (10(-5)-10(-3) M) was added to the organ baths. The study indicates the existence of an NO system within the human uterine cervix and a role of NO in control of cervical function.
Mol Hum Reprod 1998 Sep
PMID:Nitric oxide mediated inhibition of contractile activity in the human uterine cervix. 978 54

We have recently provided evidence that the concentration and activity of the enzyme nitric oxide synthase type I (NOS I) was stimulated in gonadotrophs by GnRH, suggesting a role for the NOS I/NO pathway in the GnRH control of cell functions. To further establish the GnRH regulation of pituitary NOS I under physiological circumstances, we have examined the expression of NOS I during the 4-day estrus cycle in rats. Western blot analysis demonstrated that NOS I was present in the anterior pituitary at low levels during diestrus I (DI) and diestrus II, then was subject to a significant increase on the afternoon of proestrus to reach a maximal 3-fold increase between 19:00 and 20:00 h, after which NOS I decreased to return, during estrus, to levels within the range detected in diestrus. No such variation was apparent in the posterior pituitary lobe. NADPH-diaphorase histochemistry combined with immuno-identification of the cells revealed that active NOS I was expressed in both the gonadotrophs and the folliculo-stellate cells throughout the whole cycle but only the gonadotrophs showed an up-regulation during proestrus. A high temporal correlation was observed in the profiles of NOS I, pituitary cGMP and serum luteinizing hormone (LH) suggesting an implication of GnRH. Consistently, the administration of a potent GnRH antagonist to rats totally abolished the rise in pituitary NOS I and cGMP, in addition to suppressing, as expected, the surge in the secretion of LH. A role of NOS I as a mediator in the GnRH-induced augmentation in cGMP was further established in vitro by incubating anterior pituitaries in the presence of the NOS inhibitor, L-NMMA (1 mM). Altogether, these data demonstrate that the level and activity of NOS I is up-regulated in gonadotrophs during proestrus, in a manner consistent with a major implication of GnRH over a period during which its release from the hypothalamus, as well as gonadotroph responsiveness, are at maximum. This effect is accompanied by a NOS/NO-mediated rise in cGMP. In the absence of obvious effect on gonadotropin release, the roles of NO and cGMP in the regulation of gonadotroph functions, especially during proestrus, remain to be established.
Mol Cell Endocrinol 1998 Aug 25
PMID:GnRH-dependent up-regulation of nitric oxide synthase I level in pituitary gonadotrophs mediates cGMP elevation during rat proestrus. 980 49

Several studies, including histochemical ones, have indicated that nitric oxide (NO) of endothelial origin may be related to the pulmonary vasodilation that occurs at birth. Since no histologic studies have been done of the possible parallel perinatal increase in production of neuronal NO synthase (nNOS) by pulmonary nerve plexuses, we investigated the distribution of nNOS in fetal, neonatal, and adult mouse lung. Lungs from mice aged 13 d gestation to 6 d after birth and lungs of adults were studied through histochemistry for nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) activity and immunocytochemistry. Both techniques gave almost similar results in relation to time of appearance, distribution, and frequency of neural structures positive for NADPH-d and NOS. NADPH-d staining was also applied to whole mounts of developing and adult tracheae. Staining was found from gestational days 13 to 15 onward in a small portion of the neuronal population. In all stages studied, NADPH-d/NOS staining was found in neuron cell bodies in the hilar region and bronchiolar wall, as well as in neuronal processes. Labeled terminal nerve fibers with varicosities were more frequent in pulmonary blood vessels than in airways. In tracheae, similar NADPH-d/NOS-positive nerve plexuses were found. The presence of nNOS in fetal and neonatal mouse respiratory tract suggests that neurally derived NO must play a role in developing lung physiology. However, because no perinatal increase in the number or intensity of staining of nNOS-positive nerve structures was seen, no apparent relation between neural NO and vasodilation can be established at birth.
Am J Respir Cell Mol Biol 1999 Feb
PMID:Histochemical demonstration of neuronal nitric oxide synthase during development of mouse respiratory tract. 992 27

We have previously shown that exposure of rats to constant light (LL) induced a decrease in NO synthase (NOS) activity in the pineal gland. We report here that the use of the sensitive technique of RT-PCR has demonstrated that mRNA for neuronal NOS is present in the pineal, and that it is photoneurally regulated. There was a marked decrease in pineal neuronal NOS mRNA levels in continuous light conditions, similar to the changes seen in NOS enzyme activity. Inducible NOS was not present in the pineal, and there was evidence that the photoregulatable form was not endothelial NOS. The mRNA for two isoforms of heme oxygenase, the enzyme responsible for the generation of the putative neuromodulator carbon monoxide, was also present in the pineal, but neither isoform was photoregulated. Using immunodetection, it was not possible to identify the presence of NOS protein, other than to a minimal extent, even though NOS activity was clearly present. NADPH-diaphorase staining and in situ hybridization were carried out in an attempt to identify the precise location of neuronal NOS message. A strong NADPH-diaphorase reaction was present in sympathetic nerve fibers of the pineal, but pinealocytes showed no or only very weak labelling. In situ hybridization was also unable to identify neuronal NOS message in pinealocytes. These data thus also suggest the possible presence of a pineal-specific NOS isoenzyme.
Brain Res Mol Brain Res 1999 Jul 05
PMID:Pineal nitric oxide synthase, but not heme oxygenase, mRNA is suppressed by continuous exposure to light. 1040 74

The localisation of diaphorase was visualised by light microscopy using the dye nitro blue tetrazolium and NADPH as substrates. Under appropriate conditions, diaphorase reduces this dye to a dark blue insoluble formazan. The enzyme was located at very low activity in many tissue and glandular structures of the deer, but at very much higher activity in sebaceous glands in the dermal velvet of the antler and skin, and in additional sebaceous gland-related structures in the ear canal, prepuce and tail (scent) gland. Within sebaceous glands, activity was greatest in the outermost layers of the acini, but decreased as the cells progressed and differentiated centripetally. There was little or no difference between the staining observed when NADH was used as a substrate, compared to NADPH. There was generalised staining (usually light) for glucose-6-phosphate dehydrogenase, lactate dehydrogenase, and glycerol-3-phosphate dehydrogenase. However, this staining was not specifically localised to sebaceous glands and related structures, showing that the observed activity in these structures was due to a diaphorase that was distinct from any of the dehydrogenase activities tested. The possible role of diaphorase in sebaceous development and secretion is discussed.
Comp Biochem Physiol B Biochem Mol Biol 1999 May
PMID:Diaphorase activity in sebaceous glands and related structures of the male red deer. 1042 9

The objective of the study was to assess the plausible existence of a nitric oxide (NO) system within the human Fallopian tube and to examine the effects of NO on tubal contractility. Tissue was obtained from fertile women at operations due to non-tubal diseases. Production of NO and sites of nitric oxide synthase (NOS) activity were assessed by the use of NADPH diaphorase staining and by immunoblots as well as immunohistochemistry for the isoforms of NOS. Effects of NO on tubal contractility in vitro were examined by adding either of two NO donors (nitroglycerin, spermine NONOate) or an analogue of its second messenger (8-bromo cyclic GMP). The production of NO was indicated by positive NADPH diaphorase staining. In immunoblots, endothelial and inducible NOS were demonstrated in all samples analysed. By immunohistochemistry, moderate staining for endothelial NOS was demonstrated in the luminal epithelial cells and in the endothelial cells of blood vessels. Moderate staining for inducible NO synthase was seen in smooth muscle cells and weak staining in epithelial cells. Nitroglycerin, spermine NONOate and 8-bromo cGMP all resulted in a concentration-dependent inhibition of contractility with significant contractility inhibition at 10(-7) mol/l, 10(-6) mol/l and 10(-5) mol/l respectively. The study demonstrates the existence of an endogenous NO system, which may be of physiological importance in Fallopian tube function.
Mol Hum Reprod 1999 Nov
PMID:Localization of nitric oxide synthase and effects of nitric oxide donors on the human Fallopian tube. 1054 66

When the axon of motoneurons is transected, the number of synaptic boutons contacting the cell body is decreased, and the recovery of synapses depends on muscle reinnervation. Post-synaptic density-95 (PSD-95) is a protein which is located at the post-synaptic density (PSD) and it plays a pivotal role in regulating synaptic plasticity and synaptogenesis. In addition, PSD-95 binds with neuronal nitric oxide synthase (nNOS), which is competitively inhibited by carboxy-terminal PDZ ligand of nNOS (CAPON) and, thereby, nNOS activity is thought to be regulated by PSD-95 and CAPON. We investigated the changes in mRNA for PSD-95, CAPON and nNOS in the facial motor nucleus of adult rats following axotomy, by in situ hybridization, in combination with the time course of muscle reinnervation, by retrograde tracing and nNOS protein expression, by examining nicotinamide adenine nucleotide phosphate diaphorase (NADPH-d) activity. Signals of mRNA for PSD-95 and CAPON were initially expressed in the facial motoneurons, transiently decreased following axotomy and gradually recovered to the control level. When reinnervation of the axotomized nerve into muscle was observed, mRNA expression of PSD-95 and CAPON started to recover in the facial motoneurons. It was also found that mRNA and protein expression of nNOS started to increase in the axotomized facial motoneurons just prior to the recovery of mRNA expression of PSD-95 and CAPON. These results suggest that PSD-95 and CAPON are involved in synaptogenesis and/or recovery of synaptic function in motoneurons after axotomy.
Brain Res Mol Brain Res 2000 Mar 29
PMID:Changes in mRNA for post-synaptic density-95 (PSD-95) and carboxy-terminal PDZ ligand of neuronal nitric oxide synthase following facial nerve transection. 1076 8

Using the fixation insensitive NADPH-diaphorase reaction as a histochemical marker for the enzyme nitric oxide synthase (NOS), we investigated the possible sites of putatively NOS-related NADPH-diaphorase in the brain and retrocerebral complex of the cockroach, Diploptera punctata. In the cerebral ganglion, NADPH-diaphorase expression was localized in antennal lobes, optic lobes, mushroom bodies and neurosecretory cells. The highest NADPH activity was detected in the corpora allata (CA). Spectrophotometric quantitation indicated that NADPH-diaphorase activity first increased and then decreased (cycled) in the CA of mated females. In addition, during the first ovarian cycle, NADPH-diaphorase activity fluctuated concurrently with cyclic changes in the size of corpus allatum cells. In virgin females, NADPH-diaphorase activity remained at a low level, but it increased if the neural connectives between CA and brain were severed, indicating that the brain inhibited NADPH-diaphorase expression in the CA. Although nerve terminals were abundant in the CA, NADPH-diaphorase was clearly endogenous and synthesized by glandular cells, as was shown by histochemical staining of the cytosol in all dissociated cells of the CA. We have also demonstrated NADPH-diaphorase activity in the CA of the American cockroach Periplaneta americana, the house cricket Acheta domesticus, the lepidopteran Leucania loreyi, and the fruit fly Drosophila melanogaster, suggesting that NOS occurs in the CA of most, if not all insects. It is therefore possible that corpus allatum cells release NO, along with juvenile hormone, which presumably can function as a messenger molecule.
Insect Biochem Mol Biol
PMID:Nadph-diaphorase activity in corpus allatum cells of the cockroach, Diploptera punctata. 1087 18

The presence of nitric oxide synthase (EC 1.14.23 NOS) activity is demonstrated in the tropical marine cnidarian Aiptasia pallida (Verrill). Enzyme activity was assayed by measuring the conversion of [3H]arginine to [3H]citrulline. Optimal NOS activity was found to require NADPH. Activity was inhibited by the competitive NOS inhibitor NG-methyl-L-arginine (L-NMA), but not the arginase inhibitors L-valine and L-ornithine. NOS activity was predominantly cytosolic, and was characterised by a Km for arginine of 19.05 microM and a Vmax of 2.96 pmol/min per microgram protein. Histochemical localisation of NOS activity using NADPH diaphorase staining showed the enzyme to be predominantly present in the epidermal cells and at the extremities of the mesoglea. These results provide a preliminary biochemical characterisation and histochemical localisation of NOS activity in A. pallida, an ecologically important sentinel species in tropical marine ecosystems.
Comp Biochem Physiol B Biochem Mol Biol 2000 Apr
PMID:Characterisation of nitric oxide synthase activity in the tropical sea anemone Aiptasia pallida. 1090 61


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