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1.
《Biotechnic & histochemistry》2013,88(5):333-339
AbstractWe studied the interactions between apoptosis regulator proteins (Bcl-2, p53 and caspase-9) and neuronal nitric oxide in vasopressinergic magnocellular centers of the hypothalamus using neuronal nitric oxide synthase (nNOS) gene knockout mice. nNOS gene deletion resulted in accumulation of Bcl-2, p53 and caspase-9 in the paraventricular (PVN) and supraoptic (SON) nuclei in controls. Dehydration increased the levels of all three apoptosis regulator proteins studied in nuclei of wild type mice. In the hypothalamus magnocellular centers of nNOS knockout mice, however, expression of Bcl-2, p53 and caspase-9 was unchanged after dehydration. The number of magnocellular neurons did not change in the SON and PVN of nNOS deficient mice compared to wild type, and after dehydration, cell death was not observed in either nucleus of wild type or knockout mice despite activation of apoptosis regulator protein expression. Thus, we demonstrated that gene disruption of nNOS prevents activation of Bcl-2, p53 and caspase-9 expression during water deprivation, and that nNOS deficiency did not affect survival of magnocellular neurons of the hypothalamus. 相似文献
2.
Onaga T Nagashima C Sakata T 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2000,170(5-6):469-479
The present study evaluated the role of nitric oxide in the regulation of duodenal motility and pancreatic exocrine secretion
in conscious sheep. Intravenous infusions of nitric oxide synthase inhibitors, Nω-nitro-l-arginine-methyl ester (l-NAME) and Nω-nitro-l-arginine, induced clusters of duodenal contractions like phase III of migrating motor complexes and simultaneously inhibited
flow rate, bicarbonate ion and enzyme outputs of pancreatic juice. The effects of l-NAME were inhibited by simultaneous infusion of l-arginine, but not altered by adrenergic blockade using a combined infusion of phentolamine and propranolol. Inhibition of
the pancreatic secretion occurred in coincidence with initiation of the duodenal contractions, while the pancreatic secretion
was not inhibited when the premature duodenal contractions were abolished by the l-arginine infusion. The initiation of the cluster of duodenal contractions by l-NAME was not abolished by background infusion of atropine, whereas the amplitude of contractions was significantly inhibited
by atropine. These results suggest that intrinsic nitric oxide plays a crucial role in the regulation of duodenal tone and
maintenance of continuous secretion by the exocrine pancreas in sheep. These results also implied that inhibition of pancreatic
exocrine secretion by the nitric oxide synthase inhibitor is presumably mediated in part through the contractile effect on
the duodenum.
Accepted: 27 June 2000 相似文献
3.
Brief limb ischemia was reported to protect neurons against injury induced by subsequent cerebral ischemia-reperfusion, and
this phenomenon is known as limb ischemic preconditioning (LIP). To explore the role of nitric oxide (NO) in neuroprotection
of LIP in rats, we observed changes in the content of nitric oxide (NO) and activity of NO synthase (NOS) in the serum and
CA1 hippocampus of rats after transient limb ischemic preconditioning (LIP), and the influence of NG-nitro-l-arginine methylester (l-NAME), a NOS inhibitor, on the neuroprotection of LIP against cerebral ischemia-reperfusion injury. Results showed that NO
content and NOS activity in serum increased significantly after LIP compared with the sham group. The increase showed a double
peak pattern, in which the first one appeared at time 0 (immediate time point) and the second one appeared at 48 h after the
LIP (P < 0.01). The NO content and NOS activity in the CA1 hippocampus in LIP group showed similar change pattern with the changes
in the serum, except for the first peak of up-regulation of NO content and NOS activity appeared at 6 h after LIP. Pretreatment
with l-NAME before LIP blocked the neuroprotection of LIP against subsequent cerebral ischemic insult. The blocking effect of l-NAME was abolished with pretreatment of l-Arg. These findings indicated that NO may be associated with the tolerance of pyramidal cells in the CA1 hippocampus to ischemia
induced by LIP in rats. 相似文献
4.
We examined the effect of aluminum on the permeability of the blood-brain barrier (BBB) during nitric oxide-blockade-induced
chronic hypertension in rats. Animals were given the inhibitor of nitric oxide synthase, l-NAME (N
ω-nitro-l-arginine methyl ester), for 4 wk to induce chronic hypertension. Two groups of rats were given an intraperitoneal injection
of aluminum chloride. The integrity of the BBB was assessed by a quantitative measurement for Evans blue (EB) dye. The arterial
blood pressure in l-NAME- and l-NAME plus aluminum-treated animals was significantly elevated from 115±2.8 and 110±1.7 mm Hg to 174±5.2 and 175±4.8 mm Hg,
respectively (p<0.01). The EB dye content in the brain regions of the rats in the l-NAME group was increased, but there was no statistical significance compared to the saline group. The extravasation of EB
dye was significantly increased in the brain regions of the animals treated with aluminum compared to the rats treated with
saline (p<0.05). A significantly higher EB dye content in the brain regions was observed in the l-NAME plus aluminium group compared to l-NAME, aluminum, and saline groups (p<0.01). These findings indicate that exposure to a high level of aluminum leads to an additional increase in BBB permeability
where nitric oxide-blockade-induced chronic hypertension potentiates the effect of aluminum to enhance BBB permeability to
EB dye. 相似文献
5.
In this study, we investigated whether nitric oxide (NO) modulated injury-induced neuropeptide Y (NPY) releasing and c-Fos
expression in the cuneate nucleus (CN) after median nerve transection (MNT). We first examined the temporal changes of neuronal
nitric oxide synthase (nNOS) expression in the dorsal root ganglion (DRG) and CN after MNT. Following MNT, the amounts of
nNOS-like immunoreactive (nNOS-LI) neurons in the DRG and CN significantly increased as compared with those of the sham-operated
rats. Furthermore, 4 weeks after MNT, the increases of nNOS-LI neurons in the DRG and CN were attenuated by pre-emptive lidocaine
treatment in a dose-dependent manner. Finally, 4 weeks after MNT, pre-stimulation administration of L-NAME (N
ω-Nitro-l-arginine methyl ester) or 7-NI (7-nitroindazole) suppressed the amount of NPY release from the stimulated terminals and thus
attenuated c-Fos expression in the CN. Our data implied that NO would modulate neuronal activity in the DRG and CN both after
MNT. 相似文献
6.
Isao Yokoi Yukiko Namba Hideaki Kabuto Kazunori Inada Motoyuki Iida Akitane Mori Norio Ogawa 《Neurochemical research》1996,21(10):1187-1192
Since nitric oxide (NO) is synthesized by nitric oxide synthase (NOS) froml-arginine (Arg) which has an amidino group in its molecule, we, examined the effect of 29 kinds of Arg analogues on neuronal
NOS (nNOS) activity in the rat brain. None of the Arg analogues acted as a substrate for nNOS. Diamidinocystamine, hirudonine,
and guanethidine inhibited nNOS activity to 67.3%, 64.2% and 74.1%, respectively, but their inhibitory efficiency was lower
than NG-monomethyl-l-arginine (to 36.5%) which is a well known NOS inhibitor. Dimethylguanidine and N-benzoylguanidine also significantly inhibited
nNOS activity to 88.0% and 90.7%, respectively. Whereas almost all of the NOS inhibitors previously reported were synthesizdd
by substituting the amidino nitrogen of Arg, none of these new inhibitors were substituted at this position. Furthermore,
hirudonine, which is a naturally occurring compound, was thought to act as an agonist at polyamine binding site of the N-methyl-d-aspartate type of glutamate receptor complex. It is also interesting that guanethidine, an antihypertensive agent, inhibit
nNOS activity. These new drugs are useful for the investigation not only of the chemical nature of nNOS but also of the physiologic
function of NO. 相似文献
7.
Bessem Mornagui Raja Rezg Abir Grissa Monique Duvareille Claude Gharib Abdelaziz Kamoun Saloua El-Fazaa Najoua Gharbi 《Journal of physiology and biochemistry》2010,66(4):271-281
Nitric oxide (NO) is a short-lived radical that functions as a neurotransmitter in the central nervous system and plays a
physiological role in the regulation of hypothalamic–pituitary–adrenal axis and vasopressinergic axis. In the present study,
we aimed to investigate the interaction between the generation of NO and vasopressin (AVP) and corticosterone release after
3 days of water deprivation in rats. Animals were previously treated with intraperitoneal (i.p.) saline or l-nitro-arginine methyl ester (L-NAME) injection. l-NAME is a nonspecific inhibitor of nitric oxide synthases. In control rats given i.p. saline or l-NAME, hypothalamic, pituitary, and plasma AVP levels and plasma corticosterone did not change from baseline levels (p > 0.05). Three days of water deprivation increased significantly the corticosterone levels in plasma (p < 0.01) and AVP levels in hypothalamus and plasma (p < 0.01), but not in pituitary, which showed a significant decrease. These variations were concomitant with the elevation
of nitrates/nitrates in plasma. l-NAME injection abolished significantly (p < 0.01) the elevation of plasma corticosterone and hypothalamic AVP levels induced by water deprivation. These findings showed
that in water-deprived rats, nitric oxide synthase inhibition by l-NAME inhibits corticosterone and vasopressin release, suggesting a potent stimulatory role of NO. 相似文献
8.
Huiying Li Jotaro Igarashi Joumana Jamal Weiping Yang Thomas L. Poulos 《Journal of biological inorganic chemistry》2006,11(6):753-768
Crystal structures are reported for the endothelial nitric oxide synthase (eNOS)–arginine–CO ternary complex as well as the neuronal nitric oxide synthase (nNOS) heme domain complexed with l-arginine and diatomic ligands, CO or NO, in the presence of the native cofactor, tetrahydrobiopterin, or its oxidized analogs, dihydrobiopterin and 4-aminobiopterin. The nature of the biopterin has no influence on the diatomic ligand binding. The binding geometries of diatomic ligands to nitric oxide synthase (NOS) follow the {MXY}
n
formalism developed from the inorganic diatomic–metal complexes. The structures reveal some subtle structural differences between eNOS and nNOS when CO is bound to the heme which correlate well with the differences in CO stretching frequencies observed by resonance Raman techniques. The detailed hydrogen-bonding geometries depicted in the active site of nNOS structures indicate that it is the ordered active-site water molecule rather than the substrate itself that would most likely serve as a direct proton donor to the diatomic ligands (CO, NO, as well as O2) bound to the heme. This has important implications for the oxygen activation mechanism critical to NOS catalysis. 相似文献
9.
The influences of zinc (Zn) and the nitric oxide synthase (NOS) inhibitor l-NAME on peripheral neuropeptide Y (NPY)-induced feeding in mice were investigated. Male mice received NPY (200 ng/d/mouse
subcutaneously) and were separated into four groups based on cotreatments (with or without Zn [0.1 mg/mL]) and with or without
l-NAME [0.2 mg/mL]) administered in drinking water for 10 d. A control group that received saline injection was also studied.
The results showed that NPY, with or without any studied chemicals, did not affect body weight gain or body fat content. However,
the mice that were administered NPY alone had increased energy intakes, higher serum triglyceride and free fatty acid, and
lower serum glucose than saline-injected controls. NPY-treated mice that were given Zn and l-NAME cotreatments had compatible results of determined variables in comparison with control mice. This study showed that
Zn and l-NAME attenuated NPY-mediated feeding and selected serum variables in mice. However, the mechanisms of the interactions among
NPY, Zn and NOS, and their effects on appetite regulation, remain to be elucidated. 相似文献
10.
Ya-Jie Huang Yu-Jia Yuan Yi-Xian Liu Meng-Yue Zhang Jing-Ge Zhang Tian-Ci Wang Li-Nan Zhang Yu-Yan Hu Li Li Xiao-Hui Xian Jie Qi Min Zhang 《Neurochemical research》2018,43(9):1779-1790
Previous studies have shown that intermittent hypobaric hypoxia (IH) preconditioning protected neurons survival from brain ischemia. However, the mechanism remains to be elucidated. The present study explored the role of nitric oxide (NO) in the process by measuring the expression of NO synthase (NOS) and NO levels. Male Wistar rats (100) were randomly assigned into four groups: sham group, IH?+?sham group, ischemia group and IH?+?ischemia group. Rats for IH preconditioning were exposed to hypobaric hypoxia mimicking 5000 m high-altitude (PB?=?404 mmHg, PO2?=?84 mmHg) 6 h/day, once daily for 28 days. Global brain ischemia was established by four-vessel occlusion that has been created by Pulsinelli. Rats were sacrificed at 7th day after the ischemia for neuropathological evaluation by thionin stain. In addition, the expression of neuronal NOS (nNOS), inducible NOS (iNOS), and NO content in the hippocampal CA1 subfield were measured at 2nd day and 7th day after the ischemia. Results revealed that global brain ischemia engendered delayed neuronal death (DND), both nNOS and iNOS expression up-regulated, and NO content increased in the hippocampal CA1 subfield. IH preconditioning reduced neuronal injury induced by the ischemia, and prevented the up-regulation of NOS expression and NO production. In addition, l-NAME?+?ischemia group was designed to detect whether depressing NO production could alleviate the DND. Pre-administration of l-NAME alleviated DND induced by the ischemia. These results suggest that IH preconditioning plays a protective role by inhibiting the over expression of NOS and NO content after brain ischemia. 相似文献
11.
Highly metastatic ras/myc-transformed serum-free mouse embryo (r/m HM-SFME-1) cells were injected subcutaneously to mice and the effects of Nω-nitro-l-arginine methyl ester (l-NAME) on the tumor progression and pulmonary metastasis were investigated. In addition, production of nitric oxide (NO), matrix
metalloproteinases (MMPs) and tumor necrosis factor-alpha (TNF-α) in the tumor cells and in a mouse macrophage-like cell line,
J774.1 cells, was analyzed. The increase in footpad thickness was significantly smaller in the mice which were fed the l-NAME containing water (4.24 ± 0.39 mg/day/mouse). The number of the tumor cells metastasized to the lungs was smaller in
the l-NAME treated mice, although statistical significance was not found. Co-treatment of r/m HM-SFME-1 cells with interferon-gamma (IFN-γ; 100 U/ml) and lipopolysaccharide (LPS; 0.5 μg/ml) significantly enhanced NO
production, and the presence of l-NAME at 1 mM significantly decreased this response. In r/m HM-SFME-1 cells, MMP-2 was undetectable and MMP-9 was also very little in the basal level, and both MMPs were unaffected
by the IFN-γ and/or LPS treatments, not to mention by the l-NAME treatment. In J774.1 cells, any treatment including LPS appeared to enhance MMP-9 production, however, this upregulation
was not inhibited by the additional presence of l-NAME. Production of TNF-α by J774.1 cells was markedly enhanced with LPS treatment, and this enhancement was significantly
reduced in the presence of l-NAME. These results indicate that the inhibitory effects of l-NAME on the tumor cell progression and pulmonary metastasis could be due to suppression of NO from tumor cells and TNF-α
from macrophages (Mol Cell Biochem, 2007).
Hideaki Yamaguchi and Yumi Kidachi contributed equally to this work. 相似文献
12.
Hong E Larios F Gómez-Viquez NL Huang F Bravo G 《Journal of physiology and biochemistry》2011,67(3):427-435
The contribution of α-adrenoceptors and nitric oxide (NO) on the alterations of sympathetically mediated cardiovascular responses
after acute (AcH) and chronic (ChH) hypertension was evaluated in pithed aortic coarcted hypertensive rats. Pressor and tachycardia
response produced by electrical stimulation of preganglionic sympathetic fibers or exogenous noradrenaline (NA) were recorded
in the absence and presence of prazosin (α1-antagonist), rauwolscine (α2-antagonist), or N
G-nitro-l-arginine methyl ester (l-NAME; an inhibitor of NO synthase). Compared with age-matched sham-operated rats (Nt), the pressor response produced by electrical
stimulation or NA was smaller in AcH rats and larger in ChH rats. Prazosin caused a decrease of pressor response elicited
by electrical stimulation or NA in all groups. However, this effect was higher in ChH. Rauwolscine produced a similar increase
of sympathetically mediated pressor response in Nt and AcH rats. Nevertheless, this antagonist did not affect the sympathetically
mediated pressor response in ChH rats. In addition, rauwolscine did not affect the NA-induced pressor response in all groups.
The pressor response elicited by l-NAME was larger in all groups compared without l-NAME and in presence of l-arginine. Moreover, l-NAME in the presence of NA increased sympathetically mediated pressor response is in all groups, compared without it or in
the presence of l-arginine. Compared with Nt, basally produced NO in aortic rings was increased in AcH but decreased in ChH. Collectively,
our data suggest that decreased cardiovascular reactivity in AcH is due to an increase in basally produced NO. In ChH, enhanced
cardiovascular response appears to be associated with a decrease in produced NO and an increase in released NA from sympathetic
nerves. 相似文献
13.
Sephashvili M Zhuravliova E Barbakadze T Khundadze M Narmania N Mikeladze DG 《Neurochemical research》2006,31(10):1205-1210
Homocysteine is a sulfur-containing, nonproteinogenic, neurotoxic amino acid biosynthesized during methyl cycles after demethylation of S-adenosylmethionine (SAM) to S-adenosylhomocysteine (SAH) and subsequent hydrolysis of SAH into homocysteine and adenosine. Formed homocysteine is either catabolized into cystathionine (transsulfuration pathway) by cystathionine β-synthase, or remethylated into methionine (remethylation pathway) by methionine synthase. To demonstrate the specificity of Ras-elicited effects on the activity of methyl cycles, wild-type pheochromocytoma PC12, mutant oncogenic rasH gene (MVR) expressing PC12 pheochromocytoma and normal c-rasH stably transfected M-CR3B cells were incubated with the Nω-nitro-l-arginine methyl ester (l-NAME), and manumycin, (inhibitors of nitric oxide synthase and farnesyltransferase, respectively). We have found that l-NAME significantly changes the SAM/SAH ratio in both MCR and MVR cells. Moreover, these alterations have reciprocal character; in the MCR cells, the SAM/SAH ratio was raised, whereas in the MVR cells this ratio was decreased. We conclude that depletion of endogenous NO with l-NAME increased the production of SAH only in cells with mutated oncogenic RasH, possibly through enhancement of production of reactive oxygen species (ROS). Oxidative stress can increase cystathionine β-synthase activity that switches methyl cycles from remethylation into transsulfuration pathway to maintain the intracellular glutathione pool (essential for the redox-regulating capacity of cells) via an adaptive process. 相似文献
14.
Gangping Hao Xihua Du Faxing Zhao Renjiu Shi Jianmei Wang 《Plant Cell, Tissue and Organ Culture》2009,97(2):175-185
The role of nitric oxide (NO) in UV-B-induced secondary metabolite accumulation in Ginkgo biloba callus was investigated. Overall, UV-B irradiation induced multiple biological responses in callus of G. biloba, including increased both NO production and nitric oxide synthase (NOS) activity, and subsequent activation of phenylalanine
ammonium lyase (PAL) and synthesis of flavonoids. Application of NO via the donor sodium nitroprusside (SNP) enhanced UV-B-induced
PAL activity and increased accumulation of flavonoids in G. biloba callus. Both, the NOS inhibitor l-NAME (N (G)-nitro-l-arginine methyl ester) and the NO scavenger c-PTIO (2-phenyl-4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxide) reduced the
production of NO. Moreover, UV-B-induced increase of PAL activity and flavonoid accumulation were suppressed by l-NAME and c-PTIO. These findings suggested a causal relationship between NO release and both PAL activity and flavonoid accumulation
under UV-B irradiation. In addition, it also indicated that NO, produced via NOS-like activity in ginkgo callus subjected
to UV-B irradiation, might act as an essential signaling molecule for triggering the activation of PAL and synthesis of flavonoids.
Additionally, a guanylyl cyclase inhibitor 6-anilino-5,8-quinolinequinone (LY-83583) prevented both UV-B- and SNP-induced
enhancement of PAL activation and flavonoid biosynthesis thus suggesting that the NO function was mediated by cyclic guanosine
5’-monophosphate. However, these effects of c-PTIO, l-NAME, and LY-83583 were partial, thus suggesting that there were NO-independent pathways in UV-B signaling networks.
Gangping Hao and Xihua Du are contributed equally to this article. 相似文献
15.
The aim of this study was to determine the levels of tissue and blood zinc (Zn), copper (Cu), magnesium (Mg) in nitric oxide
(NO) synthase blockade-induced hypertension. A group of albino rats received a NO synthase inhibitor, N
G
-nitro-l-arginine-methyl ester (l-NAME, 60 mg/kg/d) in their drinking water for 21 d. l-NAME intake caused a progressive rise in this group’s resting mean arterial blood pressure compared to a control group (p<0.01). There were no differences between the groups with regard to tissue and blood levels of Zn or Cu; however, Mg concentrations
were significantly lower in the hypertensive rats’ erythrocytes (20.2% reduction from control levels), cerebral cortex (17.0%),
heart (9.1%), renal cortex (12%), renal medulla (16.7%), and in the tissues of the caval vein (23.7%), mesenteric artery (29.8%),
renal artery (18.4%), and renal vein (22.1%). There were no significant Mg concentration changes in the hypertensive group’s
plasma, cerebellum, liver, duodenum, or aortal tissue. These findings suggest that Mg depletion may play a role in the blood
pressure rise that occurs in the model of chronic NO synthase inhibition-induced hypertension. 相似文献
16.
Inhibition of nitric oxide synthase enhances contractile response of ventricular myocytes from streptozotocin-diabetic rats 总被引:1,自引:0,他引:1
The contractile hyporesponsiveness of the streptozotocin diabetic rat heart in vitro to β-adrenergic agonists is eliminated
when the heart is perfused with NG-nitro-l-arginine methyl ester (l-NAME), a non-selective inhibitor of nitric oxide synthase (NOS). The following study evaluated the hypothesis that an increased
production of NO/cGMP within the diabetic myocyte inhibits the β-adrenergic-stimulated increase in calcium current and contractile
response. Male Sprague-Dawley rats were given an intravenous injection of streptozotocin (60 mg/kg). After 8 weeks, L-type
calcium currents were recorded in ventricular myocytes using the whole cell voltage-clamp method. Shortening of isolated myocytes
was determined using a video edge detection system. cAMP and cGMP were measured using radioimmunoassay. Nitric oxide production
was determined using the Griess assay kit. Basal cGMP levels and nitric oxide production were elevated in diabetic myocytes.
Shortening of the diabetic myocytes in response to isoproterenol (1 μM) was markedly diminished. However, there was no detectable
difference in the isoproterenol-stimulated L-type calcium current or cAMP levels between control and diabetic myocytes. Acute
superfusion of the diabetic myocyte with l-NAME (1 mM) decreased basal cGMP and markedly enhanced the shortening response to isoproterenol but did not alter isoproterenol-stimulated
calcium current. These data suggest that increased production of NO/cGMP within the diabetic myocyte suppressed β-adrenergic
stimulated shortening of the myocyte. However, NO/cGMP apparently does not suppress shortening of the myocyte by inhibition
of the β-stimulated calcium current. 相似文献
17.
Andréa Carla Celotto Sandra Y. Fukada Francisco R. M. Laurindo Renato Haddad Marcos N. Eberlin Ana Maria de Oliveira 《Amino acids》2010,38(5):1515-1522
Homocysteine is an independent risk factor for coronary heart disease, as well as for cerebrovascular and peripheral vascular
diseases. The purpose of this study was to investigate the effects of hyperhomocysteinemia (HHcy) on vascular reactivity within
carotid artery segments isolated from ovariectomized female rats. Treatment with dl-Hcy thiolactone (1 g/kg body weight per day) reduced the phenylephrine-induced contraction of denuded rings. However, the
treatment did not alter KCl-induced contractions, or relaxations induced by sodium nitroprusside or acetylcholine. We report
elevated expressions of iNOS, eNOS, and nitrotyrosine in homocysteine-treated rat artery sections. Moreover, the inhibition
of NOS by l-NAME, 1,400 W, or l-NNA restored phenylephrine-induced vasoconstriction in carotid artery segments from Hcy-treated rats. In conclusion, our
findings show that severe HHCy can promote an acute decrease in the endothelium-independent contractile responses of carotid
arteries to adrenergic agonists. This effect was restored by nitric oxide synthase inhibitors, which further supports the
involvement of nitric oxide in HHcy-derived vascular dysfunction. 相似文献
18.
Co-localization of nitric oxide synthase immunoreactivity and NADPH diaphorase staining in neurons of the guinea-pig intestine 总被引:1,自引:0,他引:1
H. M. Young J. B. Furness C. W. R. Shuttleworth D. S. Bredt S. H. Snyder 《Histochemistry and cell biology》1992,97(4):375-378
Summary Neuronal nitric oxide synthase (NOS), an enzyme capable of synthesizing nitric oxide, appears to be identical to neuronal NADPH diaphorase. The correlation was examined between NOS immunoreactivity and NADPH diaphorase staining in neurons of the ileum and colon of the guinea-pig. There was a one-to-one correlation between NOS immunoreactivity and NADPH diaphorase staining in all neurons examined; even the relative staining intensities obtained were similar with each technique. To determine whether pharmacological methods could be employed to demonstrate that NADPH diaphorase staining was due to the presence of NOS, tissue was pre-treated with NG-nitro-l-arginine, a NOS inhibitor, or l-arginine, a natural substrate of NOS. In these experiments on unfixed tissue, it was necessary to use dimethyl thiazolyl tetrazolium instead of nitroblue tetrazolium as the substrate for the NADPH diaphorase histochemical reaction. Neither treatment caused a significant decrease in the level of NADPH diaphorase staining, implying that arginine and NADPH interact at different sites on the enzyme. 相似文献
19.
Yoshiki Koriyama Rie Yasuda Keiko Homma Kazuhiro Mawatari Mikiko Nagashima Kayo Sugitani Toru Matsukawa Satoru Kato 《Journal of neurochemistry》2009,110(3):890-901
Nitric oxide (NO) signaling results in both neurotoxic and neuroprotective effects in CNS and PNS neurons, respectively, after nerve lesioning. We investigated the role of NO signaling on optic nerve regeneration in the goldfish ( Carassius auratus ). NADPH diaphorase staining revealed that nitric oxide synthase (NOS) activity was up-regulated primarily in the retinal ganglion cells (RGCs) 5–40 days after axotomy. Levels of neuronal NOS (nNOS) mRNA and protein also increased in the RGCs alone during this period. This period (5–40 days) overlapped with the process of axonal elongation during regeneration of the goldfish optic nerve. Therefore, we evaluated the effect of NO signaling molecules upon neurite outgrowth from adult goldfish axotomized RGCs in culture. NO donors and dibutyryl cGMP increased neurite outgrowth dose-dependently. In contrast, a nNOS inhibitor and small interfering RNA, specific for the nNOS gene, suppressed neurite outgrowth from the injured RGCs. Intra-ocular dibutyryl cGMP promoted the axonal regeneration from injured RGCs in vivo . None of these molecules had an effect on cell death/survival in this culture system. This is the first report showing that NO-cGMP signaling pathway through nNOS activation is involved in neuroregeneration in fish CNS neurons after nerve lesioning. 相似文献
20.
Despite evidence which supports a neurotransmitter-like role for nitric oxide (NO) in the CNS, relatively little is known regarding mechanisms which control NO formation within CNS neurons. In this study, isolated nerve endings (synaptosomes) from rat cerebral cortex were used to ascertain whether NO can autoregulate its own formation within neurons through feedback inhibition of the NO biosynthetic enzyme nitric oxide synthase (NOS). Under the conditions described here, N-nitro-l-arginine methyl ester-sensitive conversion ofl-[3H]arginine intol-[3H]citrulline (i.e., NOS activity) was found to be highly calcium-dependent and strongly inhibited (up to 60 percent) by NO donors, including sodium nitroprusside, hydroxylamine and nitroglycerin. The inhibitory effect of sodium nitroprusside was concentration-dependent (IC50100 M) and prevented by the NO scavenger oxyhemoglobin.l-Citrulline, the other major end-product from NOS, had no apparent effect on synaptosomal NOS activity. Taken together, these results indicate that neuronal NOS can be inhibited by NO released from exogenous donors and, therefore, may be subject to end-product feedback inhibition by NO that is formed locally within neurons or released from proximal cells. 相似文献