Possible Role Of Nitric Oxide Research Articles

Uncovering Novel Protein Partners of Inducible Nitric Oxide Synthase in Human Testis.

Peroxidative damage to human spermatozoa has been shown to be the primary cause of male infertility. The possible role of nitric oxide (NO) in affecting sperm motility, capacitation, and acrosome reaction has been reported, too. The overproduction of NO by the enzyme inducible nitric oxide synthase (iNOS) could be responsible as it has been implicated in the pathogenesis of many diseases. There have been many studies on regulating iNOS function in various tissues, especially by protein-protein interaction; however, no study has looked for iNOS-interacting proteins in the human testis. Here, we have reported the identification of two proteins that interact with iNOS. We initially undertook a popular yeast two-hybrid assay to screen a human testis cDNA library in yeast using an iNOS-peptide fragment (amino acids 181-335) as bait. We verified our data using the mammalian chemiluminescent co-IP method; first, employing the same peptide and, then, a full-length protein co-expressed in HEK293 cells in addition to the candidate protein. In both cases, these two protein partners of iNOS were revealed: (a) sperm acrosome-associated 7 protein and (b) retinoblastoma tumor-suppressor binding protein.

Protection against Morphine-Induced Inhibitory Avoidance Memory Impairment in Rat by Curcumin: Possible Role of Nitric Oxide/ cAMP-Response Element Binding Protein Pathway.

Although a substantial body of research suggests curcumin (CUR) has the preventive potential in memory impairment, the mechanism by which CUR prevents memory loss is still being investigated. This study employs an inhibitory avoidance (IA) model to investigate whether CUR can prevent morphine (Mor)-induced memory impairment as well as the possible role of cAMP-response element binding (CREB) protein, and nitric oxide (NO) signaling in this mechanism. This experimental study was conducted at the Animal Lab of the Physiology Research Center, Kashan University of Medical Sciences (Kashan, Iran) in 2018. Forty rats were randomly divided into four groups: control, CUR (pretreatment gavage of CUR [10 mg/Kg] for 35 days), Mor (7.5 mg/Kg, i.p.), and CUR+Mor (n=10 per group). Following the evaluation of the IA memory and locomotor activity of the animals, the CREB protein expression in the hippocampus and NO metabolites (NOx) level in the brain tissue were also investigated. The data were analyzed using Sigmaplot software (version 14.0) by using the ANOVA, Kruskal-Wallis, Holm-Sidak, and Dunn's post hoc tests. P<0.05 was considered to be statistically significant. In the Mor group, the IA memory of the rats was significantly impaired (P=0.001). CUR prevented the Mor-induced IA memory impairment (P=0.075). While the Mor treatment decreased the phosphorylated CREB (p-CREB) expression, the CUR+Mor cotreatment increased p-CREB expression (P=0.010). Nevertheless, the Mor treatment increased the total CREB expression (P=0.010). The NOx concentration in the brain tissue was decreased following the Mor treatment (P=0.500) but increased after the CUR+Mor cotreatment (P=0.001). The present findings suggest that CUR prevents the memory impairment of rats, possibly through NO and its downstream CREB signaling.

Molecular docking to investigate the inhibitory activity and the role of nitric oxide in anticonvulsant effects of vitamin D on pentylenetetrazole‑induced epileptic seizures in rats

Despite the great breakthroughs in the field of epilepsy studies, the present drugs are ineffective in one-third of the patients, as well as without providing a definite treatment. There is accumulating evidence suggesting the role of vitamin D in epilepsy. The aim of this study was to investigate the effect of vitamin D on seizure formation, post-seizure cognitive functions, and the possible role of nitric oxide and oxidative stress in this effect, in the PTZ-induced seizure rat model. Sixty male Wistar albino rats were used in this study. The rats were randomly divided into 11 groups each containing 6 animals: Group 1: Control; Group 2: Saline+PTZ (45 mg/kg); Group 3: Vitamin D (1.5 mg/kg)+PTZ; Group 4: L-Arginine (500 mg/kg)+PTZ; Group 5: L-NAME (60 mg/kg)+PTZ; Group 6: 7-Nitroindazole (40 mg/kg); Group 7: Aminoguanidine (100 mg/kg)+PTZ; Group 8: Vitamin D+L- Arginine+PTZ; Group 9: Vitamin D+L-NAME+PTZ; Group 10: Vitamin D+7-Nitroindazole+PTZ; Group 11: Vitamin D+Aminoguanidine+PTZ. Animal behavior was evaluated with open field and passive avoidance tests. Nitric oxide (NO), total oxidative status (TOS), and total antioxidant status (TAS) levels in the cortex and hippocampus brain regions were determined by ELISA method. The treatment of vitamin D in combination with NO inhibitors has a positive effect on the PTZ-induced seizures and ameliorate post-seizure learning deficits. Moreover, the combination of vitamin D with NO inhibitors reduced oxidative stress and NO levels after seizures in the cortex and hippocampus. Also, we employed molecular docking and density functional theory analysis to investigate the inhibitory activity, reactivity, and stability of Vitamin D with other NO inhibitors. Vitamin D supplementation could be effective as a supportive treatment drug in epileptic patients, according to the findings.

5-Aminolevulinic acid-induced salt tolerance in strawberry (cv. ‘Benihoppe’): Possible role of nitric oxide on interception of salt ions in roots

5-Aminolevunic acid (ALA) significantly improves salt tolerance of plants. In the previous work, we proposed that ALA induced H2O2 accumulation in roots of strawberry, which was involved in up-regulating Na+ transporter gene expressions to intercept Na+ in roots with less upward transport. In this study, we further hypothesize that nitric oxide (NO) is involved in ALA signaling cascade. Therefore, we applied sodium nitroprusside (SNP, NO donor), Na2WO4 (NO biosynthetic inhibitor), and 2, 4-carboxyphenyl-4, 4, 5, 5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO, NO scavenger) to the culture solution when strawberry (Fragaria × ananassa Duch. cv. ‘Benihoppe’) was stressed by 100 mM NaCl with or without exogenous ALA. The results revealed that salinity greatly impaired plant growth while 10 mg L−1 ALA or 10 µM SNP ameliorated the inhibition. When 5 µM Na2WO4 or cPTIO was co-treated, the ALA-improved salt tolerance was almost eliminated. This suggests that ALA-improved salt tolerance is dependent on NO presence. We found that salt stress caused NO, H2O2, Na+ and Cl− increases in the whole plants, while ALA induced additional increases in roots but significantly inhibited in leaves. These tissue-specific responses to ALA are important for plant salt tolerance. Our results suggest that the regulation of ALA to roots is very critical, which is mediated through NO and then H2O2 signaling to up-regulate gene expressions related with Na+ and Cl− transport, selectively retaining the harmful ions in roots with less upward transport. The hypothesis can reasonably explain how ALA-treated plants cope with harmful ions under salinity.

Increased nitric oxide availability worsens the cardiac performance during early re-perfusion period in adult rats.

Re-perfusion is the standard therapy for acute myocardial infarction, despite the associated pathologies that may contribute to irreversible myocardial injury. The present study aims to clarify the alterations in cardiac activities in response to experimental cardiac ischemic arrest followed by re-perfusion in isolated hearts perfused with nitric oxide (NO) donor, l-arginine, or NO inhibitor, Nω-Nitro-l-arginine methyl ester hydrochloride (l-NAME), to shed light on the possible role of NO in the re-perfusion process. Hearts isolated from adult Wistar rats were studied on Langendorff preparation under basal conditions and during 30min re-perfusion following 30min of total global ischemia. Rats were randomly divided into three groups; control and l-arginine or l-NAME infused heart groups. Cardiac tissue content of malondialdhyde, catalase and nitrite was also measured. Compared to the control group, both l-arginine and l-NAME infused hearts showed increased basal chronotropy and myocardial flow rate. Following ischemia and during the whole period of re-perfusion, the three groups demonstrated significant deterioration in the inotropic activity and compromised myocardial flow rate. l-arginine infused hearts revealed depressed inotropy and chronotropy, weak systolic and diastolic functions with compromised myocardial flow at early 5min of re-perfusion, yet with significantly higher myocardial flow rate by the end of re-perfusion. Reducing NO availability by l-NAME revealed mild impact on the ischemia re-perfusion induced contractile dysfunction, whereas excess NO worsens cardiac performance at the early re-perfusion period.

Nitric Oxide Increases Mitomycin-C Cytotoxicity by Generation of Reactive Oxygen Species and Induces Cell Death by Apoptosis in FancC-/- Cells

Fanconi Anemia (FA) is a rare genetic disorder and patients of FA exhibit progressive bone marrow failure, developmental defects and cancer predisposition. Mitochondrial dysfunction due to oxidative stress and higher levels of Reactive Oxygen Species (ROS) has been well documented in FA. Increase in the levels of Reactive Nitrogen Species (RNS) and Nitric Oxide Synthase (NOS) activity is often correlated with OS- related disorders which have altered mitochondrial function. Biological effects of Nitric Oxide (NO) and nitrosative stress depend on the cell type, concentration of NO, the time of incubation and cellular homeostasis. NO is known to have both prooncogenic as well as tumour -suppressing effects which are a result of regulation of S- nitrosylation, genome wide epigenetic changes and posttranslational modification of protein. NO plays strategic roles in metabolic and signalling pathways, making NO metabolism a key mediator in pathways that are responsible for supporting tumorigenesis. NO is also known to have important regulatory roles in the process of autophagy, which is an important mediator in the cross-talk with ROS and RNS. In the present study, we examined the interaction between ROS and NO, induction of apoptosis by NO and the possible role of NO in the pathogenesis of FA. Investigating the involvement of NO and NS and their interactions with the known hallmarks of FA will give a more comprehensive understanding of pathogenesis of FA.

Nitric oxide modulates tapentadol antinociceptive tolerance and physical dependence

Tapentadol, an analgesic with a dual mechanism of action, involving both μ-opioid receptor agonism and noradrenaline reuptake inhibition (MOP-NRI), was designed for the treatment of moderate to severe pain. However, the widely acknowledged risk of analgesic tolerance and development of physical dependence following sustained opioid use may hinder their effectiveness. One of the possible mechanisms behind these phenomena are alterations in nitric oxide synthase (NOS) system activity. The aim of the study was to investigate the tolerance and dependence potential of tapentadol in rodent models and to evaluate the possible role of nitric oxide (NO) in these processes. Our study showed that chronic tapentadol treatment resulted in tolerance to its antinociceptive effects to an extent similar to tramadol, but much less than morphine. A single injection of a non-selective NOS inhibitor, NG-nitro-L-arginine (L-NOArg), reversed the tapentadol tolerance. In dependence studies, repeated administration of L-NOArg attenuated naloxone-precipitated withdrawal in tapentadol-treated mice, whereas a single injection of L-NOArg was ineffective. Biochemical analysis revealed that tapentadol decreased nNOS protein levels in the dorsal root ganglia of rats following 31 days of treatment, while no significant changes were found in iNOS and eNOS protein expression. Moreover, pre-treatment with L-NOArg augmented tapentadol antinociception in an opioid- and α2-adrenoceptor-dependent manner. In conclusion, our data suggest that the NOS system plays an important role in the attenuation of tapentadol-induced tolerance and withdrawal. Thus, inhibition of NOS activity can serve as a promising treatment option for long-term tapentadol use by extending its effectiveness and improving the side-effects profile.

Atorvastatin prevents the development of diabetic neuropathic nociception by possible involvement of nitrergic system.

Diabetic neuropathy has been identified as a common complication caused by diabetes. However, its pathophysiological mechanisms are not fully understood yet. Statins, also known as HMG-CoA reductase inhibitors, alleviate the production of cholesterol. Despite this cholesterol-reducing effect of statins, several reports have demonstrated their beneficial properties in neuropathic pain. In this study, we used streptozotocin (STZ)-induced diabetic model to investigate the possible role of nitric oxide (NO) in the antineuropathic-like effect of atorvastatin. Diabetes was induced by a single injection of STZ. Male rats orally received different doses of atorvastatin for 21 days. To access the neuropathy process, the thermal threshold of rats was assessed using hot plate and tail-flick tests. Moreover, sciatic motor nerve conduction velocity (MNCV) studies were performed. To assess the role of nitric oxide, N(G)-nitro-L-arginine methyl ester (L-NAME), aminoguanidine (AG), and 7-nitroindazole (7NI) were intraperitoneally administered along with some specific doses of atorvastatin. Atorvastatin significantly reduced the hyperalgesia in diabetic rats. L-NAME pretreatment with atorvastatin showed the antihyperalgesic effect, suggesting the possible involvement of the NO pathway in atorvastatin protective action. Furthermore, co-administration of atorvastatin with AG and 7NI resulted in a significant increase in pain threshold in diabetic rats. Our results reveal that the atorvastatin protective effect on diabetic neuropathy is mediated at least in a part via the nitric oxide system.

Changes in the Relative Nitric Oxide Content in the Cortex of a Rat Brain in the Acute Ischemia Model

This study uses the electron paramagnetic resonance (EPR) method to study changes in the relative nitric oxygen content in the cortex of a rat brain in conditions of acute ischemia. Laser-induced vascular thrombosis is used as the model of ischemia. Rose bengal is administered into the bloodstream beforehand. In response to laser beaming, it generates reactive oxygen species, which induces protein coagulation, vascular wall damage, and, as a consequence, the formation of thrombus. It is shown histologically that the acute ischemic process ends a day after the laser surgery, and active remission, with the corresponding morphological changes in the area of the lesion, starts within three days. The relative nitric oxide content is determined 1 and 3 days after the brain vascular photothrombosis using the NO–Fe–DETC paramagnetic complex as a spin trap. The nitric oxide content is estimated by the extreme lower field of the EPR spectrum of this complex. It is shown that a significant increase in the relative nitric oxide (NO) content occurs on the third day after laser surgery and coincides with the beginning of remission after the acute ischemia. A possible role of nitric oxide in the remission is discussed in the study.

Participation of nitric oxide in induction of heat resistance of wheat seedlings by putrescine

Polyamines are stress plant metabolites involved in the formation of adaptive responses. Recently, they have been considered as compounds that are involved in signaling processes. However, the possible role of nitric oxide (NO) and its functional interaction with reactive oxygen species (ROS) in the realization of stress-protective effects of polyamines has been very poorly studied. The participation of NO as a signaling mediator in the induction of the heat resistance of wheat seedlings by the exogenous diamine putrescine is studied. Incubation of intact seedling roots on a 1 mM putrescine solution caused an increase in the activity of diamine oxidase and a transient increase in the content of nitric oxide and hydrogen peroxide, respectively, with peaks at 1 and 2 hours from the start of the treatment. The increase in the NO content was eliminated by the action of aminoguanidine (an inhibitor of diamine oxidase and NO synthase), but not sodium tungstate (an inhibitor of nitrate reductase). Treatment of seedlings with a scavenger of hydrogen peroxide with dimethylthiourea (DMTU) reduced the effect of increasing the NO content in roots caused by putrescine. At the same time, scavenger NO PTIO (2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) almost completely eliminated the accumulation of hydrogen peroxide in the roots, which occurred under the action of putrescine. The increase in the heat resistance of seedlings induced by the treatment with putrescine was completely eliminated under the influence of the NO PTIO scavenger, an inhibitor of diamine oxidase and NO synthase aminoguanidine, and the antioxidant DMTU. It is concluded about the functional interaction of ROS and NO as a signal intermediaries, providing the induction of protective responses and the development of plants of heat-resistance in the processing of putrescine.

Nitric oxide boosters as defensive agents against COVID-19 infection: an opinion

In the prevailing covid times, scientific community is busy in developing vaccine against COVID-19. Under such fascination this article describes the possible role of nitric oxide (NO) releasers in aiding the immune system of a human body against this dreadful pandemic disease. Despite some prodrug antiviral compounds are in practice to recover the patients suffering from covid-19, however, co-morbidity deaths are highest among the total deaths happened so far. This concurrence of a number of diseases in a patient along with this viral infection is indicative of the poor immunity. Literature background supports the use of NO as immunity boosting agent and hence, the nitric oxide releasing compounds could act as lucrative in this context. Some dietary suggestions of NO-containing food items have also been introduced in this article. Also, the profound effect of NO in relieving symptomatic severity of covid-19 has been opined in this work. Communicated by Ramaswamy H. Sarma

Tyrosine Nitration of Flagellins: a Response of Sinorhizobium meliloti to Nitrosative Stress.

Rhizobia are bacteria which can either live as free organisms in the soil or interact with plants of the legume family with, as a result, the formation of root organs called nodules in which differentiated endosymbiotic bacteria fix atmospheric nitrogen to the plant's benefit. In both lifestyles, rhizobia are exposed to nitric oxide (NO) which can be perceived as a signaling or toxic molecule. NO can act at the transcriptional level but can also modify proteins by S-nitrosylation of cysteine or nitration of tyrosine residues. However, only a few molecular targets of NO have been described in bacteria and none of them have been characterized in rhizobia. Here, we examined tyrosine nitration of Sinorhizobium meliloti proteins induced by NO. We found three tyrosine-nitrated proteins in S. meliloti grown under free-living conditions, in response to an NO donor. Two nitroproteins were identified by mass spectrometry and correspond to flagellins A and B. We showed that one of the nitratable tyrosines is essential to flagellin function in motility.IMPORTANCE Rhizobia are found as free-living bacteria in the soil or in interaction with plants and are exposed to nitric oxide (NO) in both environments. NO is known to have many effects on animals, plants, and bacteria where only a few molecular targets of NO have been described so far. We identified flagellin A and B by mass spectrometry as tyrosine-nitrated proteins in Sinorhizobium melilotiin vivo We also showed that one of the nitratable tyrosines is essential to flagellin function in motility. The results enhanced our understanding of NO effects on rhizobia. Identification of bacterial flagellin nitration opens a new possible role of NO in plant-microbe interactions.

Nitric oxide mediates the antidepressant-like effect of modafinil in mouse forced swimming and tail suspension tests.

Previous studies have suggested antidepressant properties for modafinil; however, the underlying mechanisms mediating the antidepressant effect of modafinil have not been well recognized in clinical and animal studies. Nitric oxide (NO) is involved in the pathophysiology of depression. We attempted to investigate the possible role of NO in the antidepressant-like effect of modafinil in mouse forced swimming test (FST) and tail suspension test (TST). The antidepressant-like effect of modafinil (25, 50 and 75mg/kg), alone and in combination with l-arginine, l-arg, (100mg/kg) and NG-l-arginine methyl ester, l-NAME (5mg/kg), was evaluated using FST and TST. Following behavioral tests, the hippocampi were dissected out to measure nitrite levels. Findings suggested that administration of modafinil at doses of 50 and 75mg/kg significantly reduced immobility time in the FST and TST. Furthermore, administration of l-arg and l-NAME increased and decreased, respectively, the immobility time in the FST and TST. We showed that co-administration of a sub-effective dose of modafinil (25mg/kg) plus l-NAME potentiated the antidepressant-like effect of the sub-effective dose of modafinil. In addition, co-treatment of an effective dose of modafinil (75mg/kg) with l-arg attenuated the antidepressant-like effect of the effective dose of modafinil. We showed that the antidepressant-like effect of modafinil is associated with decreased nitrite levels in the hippocampus. Our findings for the first time support that the modulation of NO, partially at least, is involved in the antidepressant-like effect of modafinil in mouse FST and TST.

Modulation of behavioral responses and CA1 neuronal death by nitric oxide in the neonatal rat's hypoxia model.

IntroductionNeonatal hypoxia leads to cognitive and movement impairments that might persist throughout life. Hypoxia impairs hippocampal blood circulation and metabolism. The exact mechanisms underlying hypoxia‐induced memory impairment are not fully understood. Nitric oxide (NO) is a key neuromodulator that regulates cerebral blood flow. In this study, we aimed to evaluate the possible role of NO on behavioral and histomorphometric changes in the hippocampus following hypoxia in neonate rats.Material and methodsNeonate male rats (n = 28) were randomly divided into 4 groups: control, hypoxia, hypoxia plus L‐NAME (20 mg/kg), and hypoxia plus L‐arginine (200 mg/kg). Drugs were injected intraperitoneally for seven consecutive days. Hypoxia was induced by keeping rats in a hypoxic chamber (7% oxygen and 93% nitrogen intensity). Ten to 14 days after hypoxia, behavioral changes were measured using a shuttle box, a rotarod, and an open field test. The histological changes in the hippocampus were measured using H&E and Nissl staining methods.ResultsFindings showed that hypoxia caused significant atrophy in the hippocampus. Furthermore, the administration of L‐NAME decreased the atrophy of the hippocampus in comparison with the hypoxic group. Behavioral results showed that hypoxia impaired memory performance and motor activity responses. Additionally, the administration of L‐NAME improved behavioral performance in a significant manner compared with the hypoxic group.ConclusionsHypoxia damaged the neurons of hippocampal CA1 region and induced memory impairment. The NOS inhibitor, L‐NAME, significantly attenuated the negative effects of hypoxia on behavior and observed changes in the hippocampus.

The possible role of nitric oxide in anti-convulsant effects of Naltrindole in seizure-induced by social isolation stress in male mice

Social isolation stress (SIS) as a chronic model of early-life stress could induce proconvulsant effects in mice. In the current study, we evaluated the role of opioid receptors (OPRs) agonists and antagonists in pro-conversant effects of SIS and the common pathway between delta-opioid receptors (DORs) and nitric oxide (NO) in stress-induced seizure. For reaching to this goal, we used pentylenetetrazol (PTZ) model of clonic-seizure to measure seizure threshold and administrated selective and non-selective OPRs agonists and antagonists in both social condition (SC) and isolated condition (IC) animals. In the next step, we administrated sub effective dose of naltrindole (NLT, 0.3 mg/kg) with sub-effective doses of nitric oxide synthesis (NOS) inhibitors including L-NAME (10 mg/kg), aminoguanidine (50 mg/kg) and 7-NI (15 mg/kg). Also, we co-administrated sub-effective dose of SNC80 (0.5 mg/kg) with sub-effective dose of l-arg (25 mg/kg) to assess the seizure threshold. In addition, we measured nitrite levels of hippocampus following administration of mentioned drugs in both SC and IC mice. Our findings showed that L-NAME and 7-NI (but not AG) increased anti-convulsant activity of NLT and l-arg increased proconvulsant effects of SNC80 in IC animals. Nitrite assay showed that co-administration of NLT plus sub-effective doses of L-NAME and 7-NI (but not AG) decreased and co-administration of SNC80 with sub-effective dose of l-arg increased nitrite levels of hippocampus in IC mice. This study suggests the role of n-NOS in anti-convulsant effects of NLT and pro-convulsant effects of SNC80 in stress-induced seizure.

Effect of Chronic Nicotine Exposure on Maternal Renal Adaptations in Pregnant Rats: The Possible Role of Nitric Oxide

Abstract Background: Nicotine exposure during pregnancy contin-ues to be a widespread public health problem, impacting both fetal and postnatal health. Although the deleterious effects of nicotine on fetal development and the newborn have been extensively investigated, few studies have focused on its negative effects on the maternal adaptations to pregnancy especially relevant on renal functions. Aim of Study: To study the effects of chronic nicotine exposure on the maternal renal adaptations during pregnancy and the possible underlying mechanisms. Material and Methods: Thirty six adult virgin female albino rats, divided into two main groups, each subdivided into three subgroups; all received treatment for four weeks. Group I (virgin): Subdivided into; saline treated: Received daily subcutaneous saline injections, nicotine treated: Received daily nicotine bitartrate (1mg/kg) subcutaneous injections, combined with transdermal nicotine patches (5.2mg nico-tine/day) application, and nicotine and L-arginine treated: Received the same nicotine therapy plus 0.25% L-arginine added to drinking. Group II (pregnant): Subdivided into; saline treated: Received daily subcutaneous injections of saline (2 weeks prior to mating and 1 st two weeks of gestation), nicotine treated: Received daily subcutaneous injections of nicotine bitartrate (1mg/kg), with transdermal nicotine patches, and nicotine and L-arginine treated): Received same nicotine therapy plus 0.25% L-arginine added to drinking water. Results: Physiological effects of the pregnancy on renal function were significantly improved by L-argini ne. Similarly, nicotine exposure to virgin group produced a significant increase in serum and urinary Na+, significant decrease in renal total protein, nitric oxide with renal oxidative stress compared to their control group. Co-administration of nicotine and L-arginine to virgin group produced a significant decrease in serum Na+, urinary albumin and renal MDA levels, and significant increase in the urinary Na+ level, renal total protein, NO and GSH levels compared to the virgin nicotine group. Similarly, nicotine administration to pregnant group produced a significant increase in serum and urinary Na+, FENa, urinary albumin levels, together with significant de-crease in GFR, UFR and renal total protein, NO and GSH levels. While co-administration of nicotine and L-arginine to pregnant group produced a significant decrease in serum Na+, FENa, urinary albumin levels, with significant increase in the GFR, UFR and renal total protein, NO and GSH levels. Conclusion: We concluded that chronic nicotine exposure potentially impaired maternal renal adaptation to pregnancy which was improved greatly by L-arginine, implicating NO as crucial player.

Possible Role of Nitric Oxide in Anxiety Following Transient Cerebral Ischemia in Mice

The possible role of nitric oxide (NO) in anxiety following transient cerebral ischemia by a 10-min bilateral carotid occlusion was examined in mice. Two days after the ischemia, mice showed a significant decrease in time spent on the open arms in the elevated plus-maze test; and likewise, they showed shortened social interaction time in the social interaction test, suggesting the induction of anxiety. Such anxiety behavior, however, was diminished 7 days after the treatment in both tests. A nonselective nitric oxide synthase (NOS) inhibitor, Nw-nitro-L-arginine methyl ester (L-NAME), and a selective inducible NOS (iNOS) inhibitor, S-ethylisothiourea (EIT), given twice after reperfusion, produced an anxiolytic effect in the elevated plus-maze test 2 days after the ischemia, while only the former produced antianxiety in the social interaction test. A relatively selective neuronal NOS (nNOS) inhibitor, 7-nitroindazole (7-NI), failed to decrease the level of anxiety in both tests. These results suggest that the production of NO participates in the anxiogenic behavior by the ischemia. Furthermore, NO generated by endothelial NOS (eNOS) or eNOS with iNOS, with no involvement of nNOS, plays an important role in the anxiety induced by the ischemia. Thus, we conclude that 10-min bilateral carotid occlusion provides a useful exploratory animal model for anxiety following transient cerebral ischemia.

ROLE OF NITRIC OXIDE IN CARDIAC PERFORMANCE DURING EXPERIMENTAL ISCHEMIC CARDIAC ARREST AND REPERFUSION

Background: Re-perfusion strategies are the current standard therapy for acute myocardial infarction, despite the spectrum of re-perfusionassociated pathologies that may contribute to irreversible myocardial injury. Aim of the work: The aim of present study is to clarify the alterations in intrinsic cardiac functions in response to cardiac ischemic arrest followed by re-perfusion in isolated hearts perfused with nitric oxide (NO) donor, Larginine, or NO inhibitor, Nω-Nitro-L-arginine methyl ester hydrochloride (L-NAME), to shed light on the possible role of NO in re-perfusion process. Materials and Methods: Cardiac activities of hearts isolated from Adult albino rats of both sexes were studied on Langendorff preparation under basal conditions and during 30 min re-perfusion following 30 min of total global ischemia. Rats were randomly allocated into three groups; control and L-arginine or L-NAME infused heart groups. Both L-arginine and LNAMEwere infused over 20 min during the baseline activity before induction of total global ischemia. Thereafter, cardiac tissue levels of malondialdhyde, catalase and nitrite were assessed. Results: Compared to the control, both L arginine and L-NAME infused hearts showed increased basal chronotropy and myocardial flow rate. Significantly depressed basal inotropic state was only observed in L-arginine group. The three studied groups demonstrated significant deterioration in the inotropic activity and compromised myocardial flow rate during the whole period of reperfusion. L-arginine infused hearts demonstrated depressed inotropy and chronotropy, weak systolic and diastolic functions with compromised myocardial flow at early 5 min of reperfusion, yet with significantly higher myocardial flow rate % recovery by the end ofreperfusion (82.7% ±3.01 in L-arginine vs. 56.4% ± 2.32 in control and 62.6% ±2.17 in L-NAME). The chronotropic activity was maintained in both the control and L-NAME infused hearts. Cardiac tissue NO showed the highest level in L-arginine group and the lowest level in L-NAME one. Both catalase and MDA were insignificantly changed among the three studied groups. Conclusion: Reducing NO availability by L-NAME revealed mild impact on the ischemia re-perfusion induced contractile dysfunction. Excess NO worsens cardiac performance at early re-perfusion. However, it may have potentially protective effect by acquiring higher the myocardial flow rate during the reperfusion.

Involvement of the nitric oxide pathway in the anti-depressant-like effects of thalidomide in mice

BackgroundThalidomide is a sedative/hypnotic agent that is currently used to treat patients suffering from multiple myeloma, myelodysplastic syndromes and erythema nodosum leprosum. Although previous studies have demonstrated that thalidomide possesses anti-depressant-like properties, the exact mechanism that thalidomide exerts this effect is not understood. In this study, we used two mouse models of depression and investigated the possible role of nitric oxide (NO), NO synthase (NOS) and inducible NOS (iNOS) in the ant-depressant-like effects of thalidomide. MethodsMale mice were injected with different doses of thalidomide intraperitoneally. In order to assess the anti-depressant-like properties of thalidomide, the immobility time of mice was assessed in the forced swimming test (FST) and tail suspension test (TST). Locomotor activity was assessed using the open-field test. To assess the role of nitric oxide, N(G)-nitro-L-arginine methyl ester (L-NAME, non-specific NOS inhibitor), aminoguanidine (selective iNOS inhibitor) or L-arginine (NO precursor) were administered intraperitoneally along with specific doses of thalidomide. ResultsThalidomide (10 mg/kg) significantly reduced immobility time in FST and TST. Aminoguanidine (50 mg/kg) and L-NAME (10 mg/kg) significantly augmented the anti-immobility effects of thalidomide (5 mg/kg). L-arginine (750 mg/kg) significantly inhibited the anti-immobility effects of thalidomide (10 mg/kg). None of the treatment groups demonstrated alteration of locomotor activity. ConclusionThalidomide exerts its anti-depressant-like effects through a mechanism dependent upon NO inhibition.

POSSIBLE ROLE OF NITRIC OXIDE IN REGULATION OF MICROCIRCULATION IN THE ORAL CAVITY TISSUES OF RAT

Possible role of Nitric oxide (NO) in terms formation of basal blood flow level in oral cavity tissue is studied using the method of hydrogen electrochemical generation in anesthetized rats.It was found that NO plays a leading role in oral mucosa and submandibular gland basal blood flow regulation and does not have any significant effect on blood circulation of the lower snout tissue.