Neuronal nitric oxide synthase/reactive oxygen species pathway is involved in apoptosis and pyroptosis in epilepsy

Dysfunction of neuronal nitric oxide synthase contributes to neurotoxicity,which triggers cell death in various neuropathological diseases,including epilepsy.Studies have shown that inhibition of neuronal nitric oxide synthase activity increases the epilepsy threshold,that is,has an anticonvulsant effect.However,the exact role and potential mechanism of neuronal nitric oxide synthase in seizures are still unclear.In this study,we performed RNA sequencing,functional enrichment analysis,and weighted gene coexpression network analysis of the hippocampus of tremor rats,a rat model of genetic epilepsy.We found damaged hippocampal mitochondria and abnormal succinate dehydrogenase level and Na+-K+-ATPase activity.In addition,we used a pilocarpine-induced N2a cell model to mimic epileptic injury.After application of neuronal nitric oxide synthase inhibitor 7-nitroindazole,changes in malondialdehyde,lactate dehydrogenase and superoxide dismutase,which are associated with oxidative stress,were reversed,and the increase in reactive oxygen species level was reversed by 7-nitroindazole or reactive oxygen species inhibitor N-acetylcysteine.Application of 7-nitroindazole or N-acetylcysteine downregulated the expression of caspase-3 and cytochrome c and reversed the apoptosis of epileptic cells.Furthermore,7-nitroindazole or N-acetylcysteine downregulated the abnormally high expression of NLRP3,gasdermin-D,interleukin-1βand interleukin-18.This indicated that 7-nitroindazole and N-acetylcysteine each reversed epileptic cell death.Taken together,our findings suggest that the neuronal nitric oxide synthase/reactive oxygen species pathway is involved in pyroptosis of epileptic cells,and inhibiting neuronal nitric oxide synthase activity or its induced oxidative stress may play a neuroprotective role in epilepsy.

The emerging role of nitric oxide in the synaptic dysfunction of vascular dementia

With an increase in global aging,the number of people affected by cerebrovascular diseases is also increasing,and the incidence of vascular dementia-closely related to cerebrovascular risk-is increasing at an epidemic rate.However,few therapeutic options exist that can markedly improve the cognitive impairment and prognosis of vascular dementia patients.Similarly in Alzheimer’s disease and other neurological disorders,synaptic dysfunction is recognized as the main reason for cognitive decline.Nitric oxide is one of the ubiquitous gaseous cellular messengers involved in multiple physiological and pathological processes of the central nervous system.Recently,nitric oxide has been implicated in regulating synaptic plasticity and plays an important role in the pathogenesis of vascular dementia.This review introduces in detail the emerging role of nitric oxide in physiological and pathological states of vascular dementia and summarizes the diverse effects of nitric oxide on different aspects of synaptic dysfunction,neuroinflammation,oxidative stress,and blood-brain barrier dysfunction that underlie the progress of vascular dementia.Additionally,we propose that targeting the nitric oxide-sGC-cGMP pathway using certain specific approaches may provide a novel therapeutic strategy for vascular dementia.

Metformin promotes angiogenesis and functional recovery in aged mice after spinal cord injury by adenosine monophosphate-activated protein kinase/endothelial nitric oxide synthase pathway

Treatment with metformin can lead to the recovery of pleiotropic biological activities after spinal cord injury.However,its effect on spinal cord injury in aged mice remains unclear.Considering the essential role of angiogenesis during the regeneration process,we hypothesized that metformin activates the adenosine monophosphate-activated protein kinase/endothelial nitric oxide synthase pathway in endothelial cells,thereby promoting microvascular regeneration in aged mice after spinal cord injury.In this study,we established young and aged mouse models of contusive spinal cord injury using a modified Allen method.We found that aging hindered the recovery of neurological function and the formation of blood vessels in the spinal cord.Treatment with metformin promoted spinal cord microvascular endothelial cell migration and blood vessel formation in vitro.Furthermore,intraperitoneal injection of metformin in an in vivo model promoted endothelial cell proliferation and increased the density of new blood vessels in the spinal cord,thereby improving neurological function.The role of metformin was reversed by compound C,an adenosine monophosphate-activated protein kinase inhibitor,both in vivo and in vitro,suggesting that the adenosine monophosphate-activated protein kinase/endothelial nitric oxide synthase pathway likely regulates metformin-mediated angiogenesis after spinal cord injury.These findings suggest that metformin promotes vascular regeneration in the injured spinal cord by activating the adenosine monophosphate-activated protein kinase/endothelial nitric oxide synthase pathway,thereby improving the neurological function of aged mice after spinal cord injury.

Identification and Pathogen Stimulation Patterns of Neuronal Nitric Oxide Synthase(nNOS)in Black Rockfish(Sebastes schlegelii)

Neuronal nitric oxide synthase(nNOS)was the producer of nitric oxide(NO)which played important gas messenger molecules in biological process.It also can take effect as immune regulation molecule in organism.Black rockfish(Sebastes schlegelii)is an important economic fish which were widely farmed in East Asia countries.Meanwhile,the pathogenic bacteria such as the Edwardsiella tarda and Vibrio anguillarum in seawater always brought serious obstacles to their healthy growth.In order to explore the expression pattern of n NOS gene under the pathogen stimulation and predict its immune function,the n NOS gene in black rockfish named Ssn NOS was identified.It was 3780 bp in length,located on chromosome 6,and contained 27 coding domain sequence(CDs).According to the phylogenetic analysis,the Ssn NOS showed closest relative to the counterpart gene of swamp eel(Monopterus albus).Meanwhile,analysis of Ssn NOS expression in various healthy tissues showed that Ssn NOS expression level was highest in healthy brain tissues,followed by intestinal tissues.In addition,Ssn NOS showed significant expression changes in response to stimulation by two pathogens.Particular in gill,the expression of Ssn NOS after pathogenic stimulation increased significantly.The Elisa analysis showed the Ssn NOS content in gills was much higher than that in other tissues at all time points.Moreover,the expression patterns of Ssn NOS in brain,intestine and kidney after stimulation by pathogens showed a distinct expression pattern which first down-regulated and then up-regulated.Therefore,the Ssn NOS may be an important signaling molecule for fish to respond rapidly in immune stimulation.

Role of hippocampal neuronal nitric oxide synthase in epilepsy

OBJECTIVE To study the function of neuronal nitric oxide synthase(nNOS) in the dentate gyrus(DG) in the pathology of epilepsy.METHODS The expression of nNOS in the DG was measured by qPCR and Western blotting in mice 3 and 12 h,1,7,14,and 60 d after treatment with pilocarpine(280 mg·kg-1,ip,one time).We constructed a type of lentiovirus encoding the full length cDNA of nNOS(LV-nNOS-GFP) and injected it and LV-GFP(1 μL) into the DG of the hippocampus 7 d after pilocarpine-induced seizure.The occurrence of epileptic spikes and spontaneous seizure(SRS)were monitored through electroencephalo-graph(EEG) and the protein expression was confirmed by Western blotting.We also constructed a lentioviral vehicle to interfere the expression of nNOS mRNA,which was named as LV-n NOSRNAi-GFP.A volume of 1 μL of LV-nNOS-RNAiGFP or LV-GFP was injected into the DG of the hippocampus 7 d before pilocarpine-induced seizure followed by EEG record and protein detection 2 months later.By EEG,we compared the susceptibility of nNOS knockout and wild-type mice to seizure induction and the development of epilepsy.In addition,we measured the influence of nNOS knockout on the excitability of dentate cells including mEPSC and mIPSC by using patch clamp technique.RESULTS Western blotting and qPCR measurement showed that the mRNA and protein expression of nNOS in the DG was not significantly changed in pilocarpinetreated mice compared with control mice.But the both m RNA and protein expression of nNOS decreased 7,14 and 60 d after treatment with pilocarpine(280 mg·kg-1,ip,one time).With infection of LV-nNOS-GFP in the DG,the decreased level of nNOS was recovered 7 d after seizure induction and the frequency of epileptic spikes and SRS were reversed by nNOS overexpression.We found that nNOS knockout caused a higher susceptive level to seizure induction by pilocarpine.Re-expression of nNOS in the DG of nNOS knockout mice relived the severity of epilepsy.By patch clamp recording,we found that there was no significant difference in the amplitude of mEPSC and mIPSC between nNOS knockout and wild-type mice,but the frequency of mEPSC was increased in nN OS knockout mice.Consistently,knockdown of nNOS by injection of LV-nNOS-RNAi-GFP into the DG caused higher frequency of epileptic spikes and SRS 2 months after pilocarpine-induced seizure.CONCLUSION Neurons expressing nNOS in the DG play an important role in the development of epilepsy.

Association of Glu298Asp Polymorphism of the En-dothelial Nitric Oxide Synthase Gene with Essential Hypertension in Elderly People

Objective: To investigate the association of Glu298Asp polymorphism of theeNOS gene with essential hypertension in elderly people. Methods: Ninety-five cases of essentialhypertension were randomly chosen from outpatients and inpatients as the study group, and an equalnumber of sexes, age-matched healthy people as the control group. Their height, weight and bloodpressure were recorded and their fasting plasma lipid concentrations were measured. Glu298Asppolymorphism of the eNOS gene was measured using the methods of PCR and RFLP. Results: Theconstituent ratio of Genotype Glu/Asp in the study group (26.3%) was higher than that in the controlgroup (12.6%, x^2 = 5. 67, P<0.05), the allelic frequency of 298Asp in the study group (13.2%) wassignificantly higher than that in the control group (6.3%, x^2 = 5.06, P<0.05). Conclusion: Glu298Asp variant of the eNOS gene may be an independent predictor in essential hypertension.

Effects of icariin on erectile function and expression of nitric oxide synthase isoforms in castrated rats

Aim： To investigate the effect of icariin on erectile function and the expression of nitric oxide synthase （NOS） isoforms in castrated rats. Methods： Thirty-two adult male Wistar rats were randomly divided into one shamoperated group （A） and three castrated groups （B, C and D）. One week after surgery, rats were treated with normal saline （groups A and B） or oral icariin （1 mg/[kg·day] for group C and 5 mg/[kg·day] for group D） for 4 weeks. One week after treatment, the erectile function of the rats was assessed by measuring intracavernosal pressure （ICP） during electrostimulation of the cavernosal nerve. The serum testosterone （ST） levels, the percent of smooth muscle （PSM） in trabecular tissue, and the expression of mRNA and proteins of neuronal nitric oxide synthase （nNOS）, inducible nitric oxide synthase （iNOS）, endothelial nitric oxide synthase （eNOS） and phosphodiesterase V （PDES） in corpus cavernosum （CC） were also evaluated. Results： ICP, PSM, ST and the expression of nNOS, iNOS, eNOS and PDE5 were significantly decreased in group B compared with those in group A （P 〈 0.01）. However, ICE PSM and the expression of nNOS and iNOS were increased in groups C and D compared with those in group B （P 〈 0.05）. Changes in ST and the expression of eNOS and PDE5 were not significant （P 〉 0.05） in groups C and D compared with those in group B. Conclusion： Oral treatment with icariin （〉 98.6 % purity） for 4 weeks potentially improves erectile function. This effect is correlated with an increase in PSM and the expression of certain NOS in the CC of castrated rats. These results suggest that icariin may have a therapeutic effect on erectile dysfunction.

Distribution of nitric oxide synthase in stomach myenteric plexus of rats

AIM: To study the distribution of nitric oxide synthase (NOS) in rat stomach myenteric plexus. METHODS: The distribution of NOS in gastric wall was studied in quantity and location by the NADPH-diaphorase (NDP) histochemical staining method and whole mount preparation technique. RESULTS: NOS was distributed in whole stomach wall, most of them were located in myenteric plexus, and distributed in submucosal plexus.The shape of NOS positive neurons was basically similar, most of them being round and oval in shape. But their density, size and staining intensity varied greatly in the different parts of stomach. The density was 62+/-38 cells mm(2) (antrum), 43+/-32 cells/mm(2) (body), and 32+/-28 cells mm(2) (fundus), respectively. The size and staining intensity of NOS positive neurons in the fundus were basically the same, the neurons being large and dark stained, while they were obviously different in antrum. In the body of the stomach, the NOS positive neurons were in an intermediate state from fundus to antrum. There were some beadlike structures which were strung together by NOS positive varicosities in nerve fibers, some were closely adherent to the outer walls of blood vessels. CONCLUSION: Nitric oxide might be involved in the modulation of motility, secretion and blood circulation of the stomach, and the significant difference of NOS positive neurons in different parts of stomach myenteric plexus may be related to the physiologic function of stomach.

Expression of inducible nitric oxide synthase and cyclooxygenase-2 in pancreatic adenocarcinoma:Correlation with microvessel density

AIM:Cydooxygenases (COX) are key enzymes for conversion of arachidonic acid to prostaglandins.Nitric oxide synthase (NOS) is the enzyme responsible for formation of nitric oxide. Both have constitutive and inducible isoforms.The inducible isoforms (iNOS and COX-2) are of great interest as regulators of tumor angiogenesis,tumorigenesis and inflammatory processes.This study was to clarify their role in pancreatic adenocarcinomas. METHODS:We investigated the immunohistochemical iNOS and COX-2 expression in 40 pancreatic ductal adenocardnomas of different grade and stage.The results were compared with microvessel density and dinicopathological data. RESULTS:Twenty-one (52.5%) of the cases showed iNOS expression,15 (37.5%) of the cases were positive for COX-2. The immunoreaction was heterogeneously distributed within the tumors.Staining intensity was different between the tumors.No correlation between iNOS and COX-2 expression was seen.There was no relationship with microvessel density. However,iNOS positive tumors developed more often distant metastases and the more malignant tumors showed a higher COX-2 expression.There was no correlation with other clinicopathological data. CONCLUSION:Approximately half of the cases expressed iNOS and COX-2.These two enzymes do not seem to be the key step in angiogenesis or carcinogenesis of pancreatic adenocarcinomas.Due to a low prevalence of COX-2 expression,chemoprevention of pancreatic carcinomas by COX-2 inhibitors can only achieve a limited success.

Expressions of inducible nitric oxide synthase and matrix metalloproteinase-9 and their effects on angiogenesis and progression of hepatocellular carcinoma

AIM： To determine the expressions of inducible nitric oxide synthase （iNOS） and matrix metalloproteinase-9 （MMP-9） in hepatocellular carcinoma （HCC） and to investigate the relationship between iNOS and MMP-9 expression and their effects on angiogenesis and progression of HCC.METHODS： In this study, we examined iNOS, MMP-9, and CD34 expression in specimens surgically removed from 32 HCC patients and 7 normal liver tissues by immunohistochemical staining. Meanwhile, microvessel density （MVD） was determined as a marker of angiogenesis by counting CD34-positive cells. RESULTS： The positive rates of iNOS and MMP-9 expression were 71.88% （23/32） and 78.13% （25/32） in HCC. MMP-9 expression was significantly correlated with tumor size, capsule status, TNM stage, and risk of HCC recurrence （P = 0.032, P= 0.033, P= 0.007, and P= 0.001, respectively）. There was also a significant relationship between iNOS expression and capsule status and risk of HCC recurrence （P = 0.049 and P = 0.004, respectively）, but no correlation between iNOS expression and tumor size and TNM stage. There was a positive association between MVD and TNM stage and risk of HCC recurrence （P = 0.037 and P = 0.000, respectively）. The count of MVD was significantly different in different iNOS and MMP-9 immunoreactivity groups （F= 17.713 and 17.097, P= 0.000 and P = 0.000, respectively）. The examination of Spearman＇s rank correlation coefficient showed that there was a significant positive correlation between MVD and iNOS, MMP-9 immunoreactivity （r = 0.754 and 0.751, P= 0.000 and P=-0.000, respectively）. There was also a significant association between MMP-9 and iNOS expression in HCC （P = 0.010）. CONCLUSION： Nitric oxide （NO） produced by iNOS could modulate MMP-9 production and therefore contribute totumor cell angiogenesis and invasion and metastasis in HCC. The strong expression of iNOS and MMP-9 in HCC may be helpful in evaluating the recurrence of HCC, predicting poor prognosis. For patients with strong expression of MMP-9 and iNOS, the optimal treatment scheme needs to be selected.

Nitric oxide synthase and heme oxygenase expressions in human liver cirrhosis

AIM： Portal hypertension is a common complication of liver cirrhosis. Intrahepatic pressure can be elevated in several ways. Abnormal architecture affecting the vasculature, an increase in vasoconstrictors and increased circulation from the splanchnic viscera into the portal system may all contribute. It follows that endogenous vasodilators may be able to alleviate the hypertension. We therefore aimed to investigate the levels of endogenous vasodilators, nitric oxide （NO） and carbon monoxide （CO） through the expression of nitric oxide synthase （NOS） and heme oxygenase （HO）. METHOD： Cirrhotic （n = 20） and non-cirrhotic （n = 20） livers were obtained from patients who had undergone surgery. The mRNA and protein expressions of the various isoforms of NOS and HO were examined using competitive PCR, Western Blot and immunohistochemistry. RESULTS： There was no significant change in either inducible NOS （iNOS） or neuronal NOS （nNOS） expressions while endothelial NOS （eNOS） was up- regulated in cirrhotic livers. Concomitantly, caveolin-1, an established down-regulator of eNOS, was upregulated. Inducible HO-1 and constitutive HO-2 were found to show increased expression in cirrhotic livers albeit in different Iocalizations. CONCLUSION： The differences of NOS expression might be due to their differing roles in maintaining liver homeostasis and/or involvement in the pathology of cirrhosis. Sheer stress within the hypertensive liver may induce increased expression of eNOS. In turn, caveolin-1 is also increased. Whether this serves as a defense mechanism against further cirrhosis or is a consequence of cirrhosis, is yet unknown. The elevated expression of HO-1 and HO-2 suggest that CO may compensate in its role as a vasodilator albeit weakly. It is possible that CO and NO have parallel or coordinated functions within the liver and may work antagonistically in the pathophysiology of portal hypertension.

Role of neuronal nitric oxide synthase and inducible nitric oxide synthase in intestinal injury in neonatal rats

AIM： TO investigate the dynamic change and role of neuronal nitric oxide synthase （nNOS） and inducible nitric oxide synthase （iNOS） in neonatal rat with intestinal injury and to define whether necrotizing enterocolitis （NEC） is associated with the levels of nitric oxide synthase （NOS） in the mucosa of the affected intestine tissue. METHODS： Wistar rats less than 24 h in age received an intraperitoneal injection with 5 mg/kg lipopolysaccharide （LPS）. Ileum tissues were collected at 1, 3, 6, 12 and 24 h following LPS challenge for histological evaluation of NEC and for measurements of nNOS and iNOS. The correlation between the degree of intestinal injury and levels of NOS was determined. RESULTS： The LPS-injected increase in injury scores pups showed a significant versus the control. The expression of nNOS protein and mRNA was diminished after LPS injection. There was a negative significant correlation between the nNOS protein and the grade of median intestinal injury within 24 h. The expression of iNOS protein and mRNA was significantly increased in the peak of intestinal injury. CONCLUSION： nNOS and iNOS play different roles in LPS-induced intestinal injury. Caution should be exerted concerning potential therapeutic uses of NOS inhibitors in NEC.

Role of brain-derived neurotrophic factor and neuronal nitric oxide synthase in stress-induced depression

BACKGROUND： Accumulated evidence indicates an important role for hippocampal dendrite atrophy in development of depression, while brain-derived neurotrophic factor （BDNF） participates in hippocampal dendrite growth. OBJECTIVE： To discuss the role of BDNF and neuronal nitric oxide synthase （nNOS） in chronic and unpredictable stress-induced depression and the pathogenesis of depression. DESIGN, TIME AND SETTING： Randomized, controlled animal experiment. The experiment was carded out from October 2006 to May 2007 at the Department of Animal Physiology, College of Life Science, Shaanxi Normal University. MATERIALS： Thirty-seven male Sprague-Dawley rats weighing 250-300 g at the beginning of the experiment were obtained from Shaanxi Provincial Institute of Traditional Chinese Medicine （Xi＇an, China）. BDNF antibody and nNOS antibody were provided by Santa Cruz （USA）. K252a （BDNF inhibitor） and 7-NI （nNOS inhibitor） were provided by Sigma （USA）. METHODS： Animals were randomly divided into five groups： Control group, chronic unpredicted mild stress （CUMS） group, K252a group, K252a＋7-NI group and 7-NI＋CUMS group. While the Control, K252a and K252a＋7-NI groups of rats not subjected to stress had free access to food and water, other groups of rats were subjected to nine stressors randomly applied for 21 days, with each stressor applied 2-3 times. On days 1, 7, 14 and 21 during CUMS, rats received microinjection of 1 μL of physiological saline in the Control and CUMS groups, 1 ~ L of K252a in the K252a group, 1 μL of K252a and 7-NI in the K252a＋7-NI group, and 1 μL of 7-NI in the 7-NI＋CUMS group. We observed a variety of alterations in sucrose preference, body weight change, open field test and forced swimming test, and observed the expression of BDNF and nNOS in rat hippocampus by immunohistochemistry; MAIN OUTCOME MEASURES： ① A variety.of behavioral alterations of rats; ② The expression of BDNF and nNOS in rat hippocampus. RESULTS： Compared with the Control group, the behavior of the CUMS rats was significantly depressed, the expression of BDNF decreased （P 〈 0.01） but the expression of nNOS increased （P 〈 0.01）. The behavior of rats given intra-hippocampal injection of BDNF inhibitor was significantly depressed and the expression of nNOS was significantly increased （P 〈 0.01）. Intra-hippocampal injections of an nNOS inhibitor reversed the depression-like behavioral changes induced by CUMS or intra-hippocampal injection of BDNF inhibitor. CONCLUSION： CUMS induced a decrease in expression of BDNF and an increase in expression of NO in the hippocampus, which may lead to depression.

Expression of nitric oxide synthase in human gastric carcinoma and its relation to p53, PCNA

AIM: To investigate the expression of NOS in gastric carcinoma, and to explore the relationship between the expression of nitric oxide synthases (NOS) and p53, PCNA,pathological features and clinical staging of gastric cancer.METHODS: The activity of NOS protein was investigated in 85 samples of human gastric carcinoma and 25 samples of normal gastric mucosal tissue by biochemical assay. We then examined the expression of NOS, p53, PCNA in 85 samples of human gastric cancer was examined by immunohistochemistry, and NOS mRNA expression in 85 gastric cancer tissue specimens by in situ hybridization.RESULTS: Biochemical assay showed that the activity of NOS was significantly higher in gastric carcinoma than in normal gastric mucosal tissues (t = 0.4161, P＜0.01).Immunohistochemistry revealed that endothelial nitric oxide synthase (eNOS) expressed in all samples of normal gastric mucosa, but only 6 cases of 85 gastric cancer specimens showed weak positive immunohistochemical reactions to eNOS (20%). Inducible nitric oxide synthase (iNOS) was expressed strongly in human gastric carcinoma (81.2%). In situ hybridization analysis showed that iNOS mRNA expression was significantly stronger than eNOS mRNA expression in gastric cancer tissue (x2 = 10.23, P＜0.01). The expression of iNOS in gastric cancer was associated with differentiation, clinical stages or lymph node metastases (r= 0.3426, P＜0.05). However,iNOS expression did not correlate with histological classifications and morphological types. The expression of iNOS was significantly correlated with p53 or PCNA expression (r = 0.3612, P＜0.05). The expression of neuronal nitric oxide synthase (nNOS) was not examined by immunohistochemistry and in situ hybridization in gastric cancer specimens and normal gastric mucosa.CONCLUSION: In human gastric cancer, there is an enhanced expression of iNOS, but not of eNOS. NOS promotes the proliferation of tumor cells and plays an important role in gastric cancer spread. Inactivation of antioncogene p53 and overexpression of iNOS might play a synergetic role in the process of carcinogenesis of human gastric carcinoma.

Distribution of constitutive nitric oxide synthase in the jejunum of adult rat

AIM: To study the distribution of the constitutive nitric oxide synthase (NOS) in the jejunum of adult rat. METHODS: The distribution of endothelial NOS (eNOS) was detected by immunohistochemistry. Immunofluorescence histochemical dual staining technique were used for studying the distribution of neuronal NOS (nNOS) and eNOS. The dual stained slides were observed under a confocal laser scanning microscope. RESULTS: Positive neuronal NOS (nNOS) and endothelial NOS (eNOS) cells were found to be distributed in lamina propria of villi, and the epithelial cell was not stained. eNOS was mainly located in submucosal vascular endothelia, while nNOS was mainly situated in myenteric plexus. Some cells in the villi had both nNOS and eNOS. More than 80% of the cells were positive for both nNOS and eNOS, the rest cells were positive either for nNOS or for eNOS. CONCLUSION: The two constitutive nitric oxide synthases are distributed differently in the jejunum of rat. nNOS distributed in myenteric plexus is a neurotransmitter in the non-adrenergic non-cholinergic (NANC) inhibitory nerves. eNOS distributed in endothelial and smooth muscle cells of blood vessels plays vasodilator role. eNOS and nNOS are coexpressed in some cells of lamina propria of villi. NO generated by those NOS is very important in the physiological and pathological process of small intestine.

Distribution of nitric oxide synthase in stomach wall in rats

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Inducible nitric oxide synthase expression is related to angiogenesis,bcl—2 and cell proliferation in hepatocellular carcinoma

In this study, we examined the expression of inducible nitric oxide s ynthase (iNOS) and vascular endothelial growth factor (VEGF) by immunohistoc hemi cal staining in 76 tissue sections collected from hepatocellular carcinoma (HCC) patients undergoing hepatectomy. Microvascular density (MVD) was determined by counting endothelial cells immunostained using anti-CD34 antibody. We performe d DNA-flow cytometric analyses to elucidate the impact of iNOS and VEGF expressi o n on the cell cycle of HCC. Most of the HCC cells that invaded stroma were mark edly immunostained by iNOS antibody. The iNOS stain intensity of the liver tissu e close to the tumor edge was stronger than that of HCC tissue, and the stronges t was the hepatocytes closer to the tumor tissue. However, iNOS expression in 10 normal hepatic samples was undetectable. VEGF positive expression ratio was 84. 8% in iNOS positive expression cases, and the ratio was 35.3% in negative cases. There was significant correlation (P=0.000) between iNOS and VEGF expressi on. Moreover, iNOS expression was significantly associated with bcl-2 and MVD, but w ithout p53 expression. DNA-flow cytometric analyses showed that combined expres s ion of iNOS and VEGF had significant impact on the cell cycle in HCC. PI (Proli ferating Index) and SPF (S-phase fraction) in the combined positive expression o f iNOS and VEGF group was significantly higher than that in the combined negativ e group. The present findings suggested that iNOS expression was significantly a ssociated with angiogenesis, bcl-2 and cell proliferation of HCC.

Effect of warm acupuncture on nitric oxide synthase and calcitonin gene-related peptide in a rat model of lumbar nerve root compression

BACKGROUND： Varying degrees of inflammatory responses occur during lumbar nerve root compression. Studies have shown that nitric oxide synthase （NOS） and calcitonin gene-related peptide （CGRP） are involved in secondary disc inflammation. OBJECTIVE： To observe the effects of warm acupuncture on the ultrastructure of inflammatory mediators in a rat model of lumbar nerve root compression, including NOS and CGRP contents. DESIGN, TIME AND SETTING： Randomized, controlled study, with molecular biological analysis, was performed at the Experimental Center, Sixth People＇s Hospital Affiliated to Shanghai Jiao Tong University, between September 2006 and April 2007. MATERIALS： Acupuncture needles and refined Moxa grains were purchased from Shanghai Taicheng Technology Development Co., Ltd., China; Mobic tablets were purchased from Shanghai Boehringer Ingelheim Pharmaceuticals Co., Ltd., China; enzyme linked immunosorbent assay （ELISA） kits for NOS and CGRP were purchased from ADL Biotechnology, Inc., USA. METHODS： A total of 50, healthy, adult Sprague-Dawley rats, were randomly divided into five groups normal, model, warm acupuncture, acupuncture, and drug, with 10 rats in each group. Rats in the four groups, excluding the normal group, were used to establish models of lumbar nerve root compression. After 3 days, Jiaji points were set using reinforcing-reducing manipulation in the warm acupuncture group. Moxa grains were burned on each needle, with 2 grains each daily. The acupuncture group was the same as the warm acupuncture group, with the exception of non-moxibustion. Mobic suspension （3.75 mg/kg） was used in the oral drug group, once a day. Treatment of each group lasted for 14 consecutive days. Modeling and medication were not performed in the normal group. MAIN OUTCOME MEASURES： The ultrastructure of damaged nerve roots was observed with transmission electron microscopy; NOS and CGRP contents were measured using ELISA. RESULTS： The changes of the radicular ultramicrostructure were characterized by Wallerian degeneration; nerve fibers were clearly demyelinated; axons collapsed or degenerated; outer Schwann cell cytoplasm was swollen and its nucleus was compacted. Compared with the normal group, NOS and CGRP contents in the nerve root compression zone in the model group were significantly increased （P 〈 0.01）. Nerve root edema was improved in the drug, acupuncture and the warm acupuncture groups over the model group. NOS and CGRP expressions were also decreased with the warm acupuncture group having the lowest concentration （P 〈 0.01）. CONCLUSION： In comparison to the known effects of Mobic drug and acupuncture treatments, the warm acupuncture significantly decreased NOS and CGRP expression which helped improve the ultrastructure of the compressed nerve root.

Simvastatin Increases the Activity of Endothelial Nitric Oxide Synthase via Enhancing Phosphorylation

3-hydroxy-3-methylgulutaryl-coenzyme A （HMG-CoA） reductase inhibitors or statins are a kind of lipid-lowering agents and have been used for the prevention and treatment of Cardiovascular diseases. Recent studies suggested that statins, besides lowering cholesterol, may protect vessels by enhancing the activity of endothelial nitric oxide synthase （eNOS）. In the present study, we investigated if simvastatin increases eNOS activity through its phosphorylation in 293 cells （293-eNOS） with stable expression of eNOS. The results showed that incubation of 293-eNOS cells with simvastatin （10 μm/L） for 2 h significantly increased in the activity of eNOS as shown by the conversion of L-arginine to L-citrulline （2889.70±201.51 versus 5630.18＋218.75 pmol/min . mg proteins） （P〈0.01）. Western blotting revealed that simvastatin increased phosphorylation of eNOS at 1177 （ser） and also 495 （thr） but did not affect the overall expression of eNOS or inducible NOS. Further study found that simvastatin raised phosphorylation levels of Akt and AMPK, and such effect could be antagonized by Akt inhibitor or AMPK inhibitor. These results suggest that simvastatin could stimulate,the activity of eNOS via its phosphorylation by Akt and AMPK, which provides a new mechanism, other than lipid-lowering effect, for the cardiovascular protection of statins.