RESUMO
There is evidence that nitric oxide (NO) modulates the metabolism of glucose and lipid, and some antihypertensive medications have been shown to affect glucose and lipid metabolism. Peristrophe bivalvis is a medicinal plant that has been shown to have antihypertensive properties. The study investigated the effect of aqueous extract of Peristrophe bivalvis leaf (APB) on fasting blood glucose level (FBG) and lipid profile in rats pretreated with nitro-L-arginine methyl ester (L-NAME). Male Wistar rats (150-170 g, n=30) were randomly divided into two groups: control (CT, n=5) and L-NAME pretreated (n=25). CT received 5 mL/kg of distilled water [DW]) while L-NAME pretreated group received 60 mg/kg of L-NAME (L-NAME60) for eight weeks. After eight weeks, the L-NAME pretreated group was randomly subdivided into L-NAME group (LN), L-NAME recovery group (LRE), L-NAME ramipril group (LRA), and L-NAME APB group (LAPB). The groups received L-NAME60+DW, DW, L-NAME60+10 mg/kg ramipril, and L-NAME60+APB (200 mg/kg), respectively, for five weeks. Serum NO, lipid profile, cyclic guanosine monophosphate (cGMP), and insulin were measured by spectrophotometry, assay kits, and ELISA, respectively. Data were analysed using ANOVA at p < 0.05. At the eighth week, a fall in FBG and an increase in triglyceride, total cholesterol, and low-density lipoprotein cholesterol were recorded in L8 compared to CT. The same effects were also noticed in the thirteenth week in LN. However, FBG was significantly increased and lipid levels were decreased in LAPB compared to LN. A significant increase was observed in cGMP level in LAPB compared to LN. The study showed that APB corrected the hyperlipidemia and hypoglycemia caused by L-NAME, and this effect might be via the activation of cGMP.
Assuntos
Glicemia , Lipídeos , NG-Nitroarginina Metil Éster , Extratos Vegetais , Folhas de Planta , Ratos Wistar , Animais , Masculino , Extratos Vegetais/farmacologia , Glicemia/metabolismo , Glicemia/efeitos dos fármacos , NG-Nitroarginina Metil Éster/farmacologia , Folhas de Planta/química , Ratos , Lipídeos/sangue , Óxido Nítrico Sintase/antagonistas & inibidores , Óxido Nítrico Sintase/metabolismo , Óxido Nítrico/metabolismo , Óxido Nítrico/sangue , Inibidores Enzimáticos/farmacologiaRESUMO
BACKGROUND: Migraine research has highlighted the pivotal role of nitric oxide (NO) in migraine pathophysiology. Nitric oxide donors such as glyceryl trinitrate (GTN) induce migraine attacks in humans, whereas spontaneous migraine attacks can be aborted by inhibiting NO production. The present study aimed to investigate how GTN triggers migraine through its three nitric oxide synthase (NOS) isoforms (neuronal NOS (nNOS), endothelial NOS (eNOS) and inducible NOS (iNOS)) via a suspected feed-forward phenomenon. METHODS: Migraine-relevant hypersensitivity was induced by repeated injection of GTN in an in vivo mouse model. Cutaneous tactile sensitivity was assessed using von Frey filaments. Signaling pathways involved in this model were dissected using non-selective and selective NOS inhibitors, knockout mice lacking eNOS or nNOS and their wild-type control mice. Also, we tested a soluble guanylate cyclase inhibitor and a peroxynitrite decomposition catalyst (Ntotal = 312). RESULTS: Non-selective NOS inhibition blocked GTN-induced hypersensitivity. This response was partially associated with iNOS, and potentially nNOS and eNOS conjointly. Furthermore, we found that the GTN response was largely dependent on the generation of peroxynitrite and partly soluble guanylate cyclase. CONCLUSIONS: Migraine-relevant hypersensitivity induced by GTN is mediated by a possible feed-forward phenomenon of NO driven mainly by iNOS but with contributions from other isoforms. The involvement of peroxynitrite adds to the notion that oxidative stress reactions are also involved.
Assuntos
Modelos Animais de Doenças , Camundongos Knockout , Transtornos de Enxaqueca , Nitroglicerina , Ácido Peroxinitroso , Animais , Transtornos de Enxaqueca/metabolismo , Transtornos de Enxaqueca/induzido quimicamente , Nitroglicerina/toxicidade , Nitroglicerina/farmacologia , Camundongos , Ácido Peroxinitroso/metabolismo , Masculino , Guanilil Ciclase Solúvel/metabolismo , Camundongos Endogâmicos C57BL , Óxido Nítrico Sintase Tipo I/metabolismo , Óxido Nítrico Sintase Tipo III/metabolismo , Óxido Nítrico Sintase/metabolismo , Óxido Nítrico Sintase/antagonistas & inibidores , Óxido Nítrico Sintase Tipo II/metabolismo , Óxido Nítrico Sintase Tipo II/antagonistas & inibidoresRESUMO
The system of nitric oxide synthases (NOSs) is comprised of three isoforms: nNOS, iNOS, and eNOS. The roles of NOSs in respiratory diseases in vivo have been studied by using inhibitors of NOSs and NOS-knockout mice. Their exact roles remain uncertain, however, because of the non-specificity of inhibitors of NOSs and compensatory up-regulation of other NOSs in NOS-KO mice. We addressed this point in our triple-n/i/eNOSs-KO mice. Triple-n/i/eNOSs-KO mice spontaneously developed pulmonary emphysema and displayed exacerbation of bleomycin-induced pulmonary fibrosis as compared with wild-type (WT) mice. Triple-n/i/eNOSs-KO mice exhibited worsening of hypoxic pulmonary hypertension (PH), which was reversed by treatment with sodium nitrate, and WT mice that underwent triple-n/i/eNOSs-KO bone marrow transplantation (BMT) also showed aggravation of hypoxic PH compared with those that underwent WT BMT. Conversely, ovalbumin-evoked asthma was milder in triple-n/i/eNOSs-KO than WT mice. These results suggest that the roles of NOSs are different in different pathologic states, even in the same respiratory diseases, indicating the diversity of the roles of NOSs. In this review, we describe these previous studies and discuss the roles of NOSs in respiratory health and disease. We also explain the current state of development of inorganic nitrate as a new drug for respiratory diseases.
Assuntos
Camundongos Knockout , Animais , Camundongos , Óxido Nítrico Sintase/metabolismo , Óxido Nítrico Sintase/genética , Humanos , Óxido Nítrico Sintase Tipo III/metabolismo , Óxido Nítrico Sintase Tipo III/genética , Hipertensão Pulmonar/genética , Hipertensão Pulmonar/metabolismo , Fibrose Pulmonar/genética , Fibrose Pulmonar/metabolismo , Fibrose Pulmonar/patologiaRESUMO
Previously, we showed the antitumor activity of the new NOS/PDK inhibitor T1084 (1-isobutanoyl-2-isopropylisothiourea dichloroacetate). The present study included an assessment of in vitro cytotoxicity against human malignant and normal cells according to the MTT-test and in vivo antitumor effects in solid tumor models in comparison with precursor compounds T1023 (NOS inhibitor; 1-isobutanoyl-2-isopropylisothiourea hydrobromide) and Na-DCA (PDK inhibitor; sodium dichloroacetate), using morphological, histological, and immunohistochemical methods. The effects of T1084 and T1023 on the in vitro survival of normal (MRC-5) and most malignant cells (A375, MFC-7, K562, OAW42, and PC-3) were similar and quantitatively equal. At the same time, melanoma A375 cells showed 2-2.5 times higher sensitivity (IC50: 0.39-0.41 mM) to the cytotoxicity of T1023 and T1084 than other cells. And only HeLa cells showed significantly higher sensitivity to the cytotoxicity of T1084 compared to T1023 (IC50: 0.54 ± 0.03 and 0.81 ± 0.02 mM). Comparative studies of the in vivo antitumor effects of Na-DCA, T1023, and T1084 on CC-5 cervical cancer and B-16 melanoma in mice were conducted with subchronic daily i.p. administration of these agents at an equimolar dose of 0.22 mmol/kg (33.6, 60.0, and 70.7 mg/kg, respectively). Cervical cancer CC-5 fairly quickly evaded the effects of both Na-DCA and T1023. So, from the end of the first week of Na-DCA or T1023 treatment, the tumor growth inhibition (TGI) began to decrease from 40% to an insignificant level by the end of the observation. In contrast, in two independent experiments, CC-5 showed consistently high sensitivity to the action of T1084: a significant antitumor effect with high TGI (43-58%) was registered throughout the observation, without any signs of neoplasia adaptation. The effect of precursor compounds on melanoma B-16 was either minimal (for Na-DCA) or moderate (for T1023) with TGI only 33%, which subsequently decreased by the end of the experiment. In contrast, the effect of T1084 on B-16 was qualitatively more pronounced and steadily increasing; it was accompanied by a 3-fold expansion of necrosis and dystrophy areas, a decrease in proliferation, and increased apoptosis of tumor cells. Morphologically, the T1084 effect was 2-fold superior to the effects of T1023-the TGI index reached 59-62%. This study suggests that the antitumor effects of T1084 develop through the interaction of NOS-dependent and PDK-dependent pathophysiological effects of this NOS/PDK inhibitor. The NOS inhibitory activity of T1084 exerts an anti-angiogenic effect on neoplasia. At the same time, the PDK inhibitory activity of T1084 enhances the cytotoxicity of induced intratumoral hypoxia and suppresses the development of neoplasia adaptation to anti-angiogenic stress. Such properties allow T1084 to overcome tumor resistance and realize a stable synergistic antitumor effect.
Assuntos
Antineoplásicos , Humanos , Animais , Camundongos , Antineoplásicos/farmacologia , Óxido Nítrico Sintase/antagonistas & inibidores , Óxido Nítrico Sintase/metabolismo , Linhagem Celular Tumoral , Tioureia/análogos & derivados , Tioureia/farmacologia , Tioureia/uso terapêutico , Ensaios Antitumorais Modelo de Xenoenxerto , Piruvato Desidrogenase Quinase de Transferência de Acetil/antagonistas & inibidores , Feminino , Inibidores Enzimáticos/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Células HeLaRESUMO
Ginseng, from the roots of Panax ginseng C. A. Meyer, is a widely used herbal medicine in Asian countries, known for its excellent therapeutic properties. The growth of P. ginseng is depend on specific and strict environments, with a preference for wetness but intolerance for flooding. Under excessive soil moisture, some irregular rust-like substances are deposited on the root epidermis, causing ginseng rusty symptoms (GRS). This condition leads to a significant reduce in yield and quality, resulting in substantial economic loses. However, there is less knowledge on the cause of GRS and there are no effective treatments available for its treatment once it occurs. Unsuitable environments lead to the generation of large amounts of reactive oxygen species (ROS). We investigated the key indicators associated with the stress response during different physiological stages of GRS development. We observed a significant change in ROS level, MDA contents, antioxidant enzymes activities, and non-enzymatic antioxidants contents prior to the GRS. Through the analysis of soil features with an abundance of moisture, we further determined the source of ROS. The levels of nitrate reductase (NR) and nitric oxide synthase (NOS) activities in the inter-root soil of ginseng with GRS were significantly elevated compared to those of healthy ginseng. These enzymes boost nitric oxide (NO) levels, which in turn showed a favorable correlation with the GRS. The activities of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase first rose and then decreased as GRS developed. Excess soil moisture causes a decrease in oxygen levels. This activated NR and NOS in the soil, resulting in a production of excess NO. The NO then diffused into the ginseng root and triggered a burst of ROS through NADPH located on the cell membrane. Additionally, Fe2+ in soil was oxidized to red Fe3+, and finally led to GRS. This conclusion was also verified by the Sodium Nitroprusside (SNP), a precursor compound producing NO. The presence of NO from NR and NOS in water-saturated soil is responsible for the generation of ROS. Among these, NO is the main component that contribute to the occurrence of GRS.
Assuntos
Óxido Nítrico , Panax , Raízes de Plantas , Espécies Reativas de Oxigênio , Solo , Panax/metabolismo , Raízes de Plantas/metabolismo , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/efeitos dos fármacos , Óxido Nítrico/metabolismo , Solo/química , Espécies Reativas de Oxigênio/metabolismo , Estresse Fisiológico , Antioxidantes/metabolismo , Óxido Nítrico Sintase/metabolismo , Nitrato Redutase/metabolismo , Doenças das PlantasRESUMO
Cocoa flavan-3-ols affect endothelium-dependent responses in resistance vessels and microcirculation has received little attention. We tested the effects of dark chocolate consumption (396 mg total flavanols/day for 3 days) in two Groups of 10 men (18-25 years; non-smokers) each comprising equal numbers of White European (WE) and South Asian (SA) ethnicity. In Group 1, dark chocolate did not affect reactive hyperaemia in forearm muscle, but augmented muscle dilatation evoked by acute mental stress, and reactive hyperaemia and acetylcholine (ACh)-evoked dilatation in cutaneous microcirculation. Conversely, in Group 2, chocolate did not affect cutaneous reactive hyperaemia or ACh-evoked dilatation, but these responses were blunted in Group 1 relative to Group 2. Further, when Groups 1 and 2 were combined, responses were blunted in SAs relative to WEs, augmented by chocolate in SAs only. In Group 2 individuals whose ACh-evoked dilatation was attenuated by nitric oxide synthase (NOS) inhibition, ACh-evoked dilatation was not altered after chocolate, but the attenuating effect of NOS inhibition was lost. Conversely, in Group 2 individuals whose ACh-evoked dilatation was enhanced by NOS inhibition, ACh-evoked dilatation was also augmented by chocolate. We propose that in resistance and microvessels of young men, cocoa flavan-3-ols preferentially augment endothelium-dependent dilator responses whose responses are depressed by familial and lifestyle factors more prevalent in SAs than Wes. Flavan-3-ols may facilitate the NOS pathway but also influence other endothelium-dependent dilators.
Assuntos
Cacau , Chocolate , Estilo de Vida , Microcirculação , Adolescente , Adulto , Humanos , Masculino , Adulto Jovem , Acetilcolina/farmacologia , Cacau/química , Endotélio Vascular/efeitos dos fármacos , Flavonoides/farmacologia , Antebraço/irrigação sanguínea , Hiperemia , Microcirculação/efeitos dos fármacos , Microvasos/efeitos dos fármacos , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/metabolismo , Óxido Nítrico Sintase/metabolismo , Pele/irrigação sanguínea , Pele/efeitos dos fármacos , Pele/metabolismo , Estresse Psicológico , Vasodilatação/efeitos dos fármacos , População Branca , População do Sul da ÁsiaRESUMO
The G-protein-coupled estrogen receptor (GPER) has been described to exert several cardioprotective effects. However, the exact mechanism involved in cardiac protection remains unclear. The aim of this study is to investigate the role of GPER activation on excitation-contraction coupling (ECC) and the possibility that such effect participates in cardioprotection. The cardiac myocytes of male Wistar rats were isolated with a digestive buffer and loaded with Fura-2-AM for the measurement of intracellular calcium transient (CaT). Sarcomere shortening (SS) and L-type calcium current (ICaL) were also registered. The confocal technique was used to measure nitric oxide (NO) production in cells loaded with DAF-FM-diacetate. Cardiac myocytes exposed to 17-ß-estradiol (E2, 10 nM) or G-1 (1 µM) for fifteen minutes decreased CaT, SS, and ICaL. These effects were prevented using G-36 (antagonist of GPER, 1 µM), L-Name (NO synthase -NOS- inhibitor, 100 nM), or wortmannin (phosphoinositide-3-kinase -PI3K- inhibitor, 100 nM). Moreover, G1 increased NO production, and this effect was abolished in the presence of wortmannin. We concluded that the selective activation of GPER with E2 or G1 in the isolated cardiac myocytes of male rats induced a negative inotropic effect due to the reduction in ICaL and the decrease in CaT. Finally, the pathway that we proposed to be implicated in these effects is PI3K-NOS-NO.
Assuntos
Acoplamento Excitação-Contração , Miócitos Cardíacos , Óxido Nítrico , Fosfatidilinositol 3-Quinases , Receptores Acoplados a Proteínas G , Animais , Masculino , Ratos , Estradiol/farmacologia , Estradiol/metabolismo , Acoplamento Excitação-Contração/efeitos dos fármacos , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/efeitos dos fármacos , Óxido Nítrico/metabolismo , Óxido Nítrico Sintase/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Ratos Wistar , Receptores de Estrogênio/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Transdução de Sinais/efeitos dos fármacosRESUMO
Radiotherapy (RT), essential for treating various cancers, faces challenges from tumor hypoxia, which induces radioresistance. A tumor-targeted "prosthetic-Arginine" coassembled nanozyme system, engineered to catalytically generate nitric oxide (NO) and oxygen (O2) in the tumor microenvironment (TME), overcoming hypoxia and enhancing radiosensitivity is presented. This system integrates the prosthetic heme of nitric oxide synthase (NOS) and catalase (CAT) with NO-donating Fmoc-protected Arginine and Ru3+ ions, creating HRRu nanozymes that merge NOS and CAT functionalities. Surface modification with human heavy chain ferritin (HFn) improves the targeting ability of nanozymes (HRRu-HFn) to tumor tissues. In the TME, strategic arginine incorporation within the nanozyme allows autonomous O2 and NO release, triggered by endogenous hydrogen peroxide, elevating NO and O2 levels to normalize vasculature and improve blood perfusion, thus mitigating hypoxia. Employing the intrinsic O2-transporting ability of heme, HRRu-HFn nanozymes also deliver O2 directly to the tumor site. Utilizing esophageal squamous cell carcinoma as a tumor model, the studies reveal that the synergistic functions of NO and O2 production, alongside targeted delivery, enable the HRRu-HFn nanozymes to combat tumor hypoxia and potentiate radiotherapy. This HRRu-HFn nanozyme based approach holds the potential to reduce the radiation dose required and minimize side effects associated with conventional radiotherapy.
Assuntos
Óxido Nítrico , Oxigênio , Óxido Nítrico/metabolismo , Óxido Nítrico/química , Humanos , Oxigênio/química , Oxigênio/metabolismo , Animais , Linhagem Celular Tumoral , Hipóxia Tumoral/efeitos dos fármacos , Catálise , Microambiente Tumoral/efeitos dos fármacos , Camundongos , Catalase/química , Catalase/metabolismo , Arginina/química , Óxido Nítrico Sintase/metabolismoRESUMO
Insulin, a critical hormone in the human body, exerts its effects by binding to insulin receptors and regulating various cellular processes. While nitric oxide (NO) plays an important role in insulin secretion and acts as a mediator in the signal transduction pathway between upstream molecules and downstream effectors, holds a significant position in the downstream signal network of insulin. Researches have shown that the insulin-NO system exhibits a dual regulatory effect within the central nervous system, which is crucial in the regulation of diabetic encephalopathy (DE). Understanding this system holds immense practical importance in comprehending the targets of existing drugs and the development of potential therapeutic interventions. This review extensively examines the characterization of insulin, NO, Nitric oxide synthase (NOS), specific NO pathway, their interconnections, and the mechanisms underlying their regulatory effects in DE, providing a reference for new therapeutic targets of DE.
Assuntos
Insulina , Óxido Nítrico Sintase , Óxido Nítrico , Transdução de Sinais , Humanos , Insulina/metabolismo , Óxido Nítrico/metabolismo , Animais , Óxido Nítrico Sintase/metabolismo , Encefalopatias Metabólicas/metabolismo , Complicações do Diabetes/metabolismoRESUMO
Nitric oxide (NO) has been defined as the "miracle molecule" due to its essential pleiotropic role in living systems. Besides its implications in physiologic functions, it is also involved in the development of several disease states, and understanding this ambivalence is crucial for medicinal chemists to develop therapeutic strategies that regulate NO production without compromising its beneficial functions in cell physiology. Although nitric oxide synthase (NOS), i.e., the enzyme deputed to the NO biosynthesis, is a well-recognized druggable target to regulate NO bioavailability, some issues have emerged during the past decades, limiting the progress of NOS modulators in clinical trials. In the present review, we discuss the most promising advancements in the research of small molecules that are able to regulate NOS activity with improved pharmacodynamic and pharmacokinetic profiles, providing an updated framework of this research field that could be useful for the design and development of new NOS modulators.
Assuntos
Inibidores Enzimáticos , Óxido Nítrico Sintase , Óxido Nítrico , Humanos , Óxido Nítrico Sintase/metabolismo , Animais , Óxido Nítrico/metabolismo , Inibidores Enzimáticos/farmacologia , Inibidores Enzimáticos/química , Inibidores Enzimáticos/uso terapêuticoRESUMO
Insulin resistance (IR) being the major cause behind different metabolic disorders, has attracted a lot of attention. Epidemiological data shows marked rise in the cases over a period of time. Nitric oxide (NO), produced from nitric oxide synthases (NOS), is involved in a variety of biological functions, alteration in which causes various disorders like hypertension, atherosclerosis, and angiogenesis-associated disorders. IR has been found to be a contributing factor, which is associated with abnormal NO signalling. Skeletal muscle is essential for metabolism, both for its role in glucose uptake and its importance in metabolic disease. In this article, we give an overview of the significance of NO in oxidative stress (OS) mediated IR, describing its role in different conditions that are associated with skeletal muscle IR. NO is found to be involved in the activation of insulin receptor downstream pathway, which suggests absence of NO could lead to reduced glucose uptake, and may ultimately result in IR.
Assuntos
Resistência à Insulina , Músculo Esquelético , Óxido Nítrico , Estresse Oxidativo , Transdução de Sinais , Óxido Nítrico/metabolismo , Humanos , Músculo Esquelético/metabolismo , Animais , Receptor de Insulina/metabolismo , Glucose/metabolismo , Óxido Nítrico Sintase/metabolismo , Insulina/metabolismoRESUMO
Caveolin is a structural protein within caveolae that may be involved in transmembrane molecular transport and/or various intercellular interactions within cells. Specific mutations of caveolin-3 in muscle fibers are well known to cause limb-girdle muscular dystrophy. Altered expression of caveolin-3 has also been detected in Duchenne muscular dystrophy, which may be a part of the pathological process leading to muscle weakness. Interestingly, it has been shown that the renovation of nitric oxide synthase (NOS) in sarcolemma with muscular dystrophy could improve muscle health, suggesting that NOS may be involved in the pathology of muscular dystrophy. Here, we summarize the notable function of caveolin and/or NOS in skeletal muscle fibers and discuss their involvement in the pathology as well as possible tactics for the innovative treatment of muscular dystrophies.
Assuntos
Caveolina 3 , Distrofias Musculares , Óxido Nítrico Sintase , Animais , Humanos , Cavéolas/metabolismo , Caveolina 3/metabolismo , Caveolina 3/genética , Caveolinas/metabolismo , Distrofias Musculares/metabolismo , Distrofias Musculares/genética , Distrofias Musculares/patologia , Distrofia Muscular de Duchenne/metabolismo , Distrofia Muscular de Duchenne/genética , Distrofia Muscular de Duchenne/patologia , Mutação , Óxido Nítrico Sintase/metabolismo , Óxido Nítrico Sintase/genéticaRESUMO
As a free radical and endogenous effector molecule, mammalian endogenous nitric oxide (NO) is mainly derived from nitric oxide synthase (NOS) via L-arginine. NO participates in normal physiological reactions and provides immune responses to prevent the invasion of foreign bacteria. However, NO also has complex and contradictory biological effects. Abnormal NO signaling is involved in the progression of many diseases, such as cancer. In the past decades, cancer research has been closely linked with NOS/ NO, and many tumors with poor prognosis are associated with high expression of NOS. In this review, we give a overview of the biological effects of NOS/ NO. Then we focus on the oncogenic role of iNOS/ NO in HPV, HBV, EBV and H. pylori related tumors. In fact, there is growing evidence that iNOS could be used as a potential therapeutic target in cancer therapy. We emphasize that the pro-tumor effect of NOS/ NO is greater than the anti-tumor effect.
Assuntos
Neoplasias , Óxido Nítrico , Humanos , Óxido Nítrico/metabolismo , Neoplasias/tratamento farmacológico , Óxido Nítrico Sintase Tipo II/metabolismo , Animais , Óxido Nítrico Sintase/metabolismo , Transdução de Sinais , Helicobacter pylori/patogenicidade , Infecções por Helicobacter/tratamento farmacológico , Infecções por Helicobacter/microbiologia , Infecções por Helicobacter/patologiaRESUMO
Nitric oxide (NO) is a molecule involved in plasticity across levels and systems. The role of NOergic pathways in stress-induced sensitization (SIS) of behavioral responses, in which a particular stressor triggers a state of hyper-responsiveness to other stressors after an incubation period, was assessed in adult zebrafish. In this model, adult zebrafish acutely exposed to a fear-inducing conspecific alarm substance (CAS) and left undisturbed for an incubation period show increased anxiety-like behavior 24 h after exposure. CAS increased forebrain glutamate immediately after stress and 30 min after stress, an effect that was accompanied by increased nitrite levels immediately after stress, 30 min after stress, 90 min after stress, and 24 h after stress. CAS also increased nitrite levels in the head kidney, where cortisol is produced in zebrafish. CAS-elicited nitrite responses in the forebrain 90 min (but not 30 min) after stress were prevented by a NOS-2 blocker. Blocking NOS-1 30 min after stress prevents SIS; blocking NOS-2 90 min after stress also prevents stress-induced sensitization, as does blocking calcium-activated potassium channels in this latter time window. Stress-induced sensitization is also prevented by blocking guanylate cyclase activation in both time windows, and cGMP-dependent channel activation in the second time window. These results suggest that different NO-related pathways converge at different time windows of the incubation period to induce stress-induced sensitization.
Assuntos
Comportamento Animal , GMP Cíclico , Peixe-Zebra , Animais , GMP Cíclico/metabolismo , Comportamento Animal/efeitos dos fármacos , Estresse Psicológico/metabolismo , Estresse Psicológico/psicologia , Transdução de Sinais , Óxido Nítrico Sintase/metabolismo , Óxido Nítrico/metabolismo , MasculinoRESUMO
Our prior investigations have established that Inonotus obliquus (Chaga) possesses hypoglycemic effects. Persistent hyperglycemia is known to precipitate renal function abnormalities. The functionality of the kidneys is intricately linked to the levels of cyclic guanosine-3',5'-monophosphate (cGMP), which are influenced by the activities of nitric oxide synthase (NOS) and phosphodiesterase (PDE). Enhanced cGMP levels can be achieved either through the upregulation of NOS activity or the downregulation of PDE activity. The objective of the current study is to elucidate the effects of Chaga on disorders of glucolipid metabolism and renal abnormalities in rats with type 2 diabetes mellitus (T2DM), while concurrently examining the NOS-cGMP-PDE5 signaling pathway. A model of T2DM was developed in rats using a high-fat diet (HFD) combined with streptozotocin (STZ) administration, followed by treatment with Chaga extracts at doses of 50 and 100 mg·kg-1 for eight weeks. The findings revealed that Chaga not only mitigated metabolic dysfunctions, evidenced by improvements in fasting blood glucose, total cholesterol, triglycerides, and insulin resistance, but also ameliorated renal function markers, including serum creatinine, urine creatinine (UCr), blood urea nitrogen, 24-h urinary protein, and estimated creatinine clearance. Additionally, enhancements in glomerular volume, GBM thickness, podocyte foot process width (FPW), and the mRNA and protein expressions of podocyte markers, such as nephrin and wilms tumor-1, were observed. Chaga was found to elevate cGMP levels in both serum and kidney tissues by increasing mRNA and protein expressions of renal endothelial NOS and neural NOS, while simultaneously reducing the expressions of renal inducible NOS and PDE5. In summary, Chaga counteracts HFD/STZ-induced glucolipid metabolism and renal function disturbances by modulating the NOS-cGMP-PDE5 signaling pathway. This research supports the potential application of Chaga in the clinical prevention and treatment of T2DM and diabetic nephropathy (DN), with cGMP serving as a potential therapeutic target.
Assuntos
GMP Cíclico , Nucleotídeo Cíclico Fosfodiesterase do Tipo 5 , Dieta Hiperlipídica , Inonotus , Rim , Óxido Nítrico Sintase , Transdução de Sinais , Animais , GMP Cíclico/metabolismo , Masculino , Transdução de Sinais/efeitos dos fármacos , Nucleotídeo Cíclico Fosfodiesterase do Tipo 5/metabolismo , Rim/efeitos dos fármacos , Rim/metabolismo , Dieta Hiperlipídica/efeitos adversos , Ratos , Óxido Nítrico Sintase/metabolismo , Óxido Nítrico Sintase/genética , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/tratamento farmacológico , Ratos Sprague-Dawley , Estreptozocina , Humanos , Diabetes Mellitus Experimental/tratamento farmacológico , Diabetes Mellitus Experimental/metabolismo , Glicemia/metabolismo , Glicemia/efeitos dos fármacos , Hipoglicemiantes/farmacologiaRESUMO
Substances of silver nanoparticles dialyzed through a 13 kDa membrane, synthesized in a medium of humic ligands modified with hydroquinone and 2-hydroxynaphthoquinone from PowHumus brown coal, specifically enhance the M2 properties of peritoneal macrophages due to inhibition of NO synthase and significant activation of arginase, thus enhancing anti-inflammatory properties of cells. In small, but effective concentrations, they do not have cytotoxic properties and do not contain pyrogenic impurities. The studied humates are able to influence the mechanisms of immune response formation and are an effective means for correcting inflammation and regeneration.
Assuntos
Arginase , Arginina , Substâncias Húmicas , Macrófagos Peritoneais , Prata , Animais , Macrófagos Peritoneais/efeitos dos fármacos , Macrófagos Peritoneais/metabolismo , Camundongos , Arginina/farmacologia , Arginina/química , Arginase/metabolismo , Prata/química , Prata/farmacologia , Nanopartículas Metálicas/química , Hidroquinonas/farmacologia , Hidroquinonas/química , Masculino , Óxido Nítrico/metabolismo , Óxido Nítrico Sintase/metabolismo , Naftoquinonas/farmacologia , Naftoquinonas/químicaRESUMO
The exchange protein directly activated by cAMP (EPAC) has been implicated in cardiac proarrhythmic signaling pathways including spontaneous diastolic Ca2+ leak from sarcoplasmic reticulum and increased action potential duration (APD) in isolated ventricular cardiomyocytes. The action potential (AP) lengthening following acute EPAC activation is mainly due to a decrease of repolarizing steady-state K+ current (IKSS) but the mechanisms involved remain unknown. This study aimed to assess the role of EPAC1 and EPAC2 in the decrease of IKSS and to investigate the underlying signaling pathways. AP and K+ currents were recorded with the whole cell configuration of the patch-clamp technique in freshly isolated rat ventricular myocytes. EPAC1 and EPAC2 were pharmacologically activated with 8-(4-chlorophenylthio)-2'-O-methyl-cAMP acetoxymethyl ester (8-CPTAM, 10 µmol/L) and inhibited with R-Ce3F4 and ESI-05, respectively. Inhibition of EPAC1 and EPAC2 significantly decreased the effect of 8-CPTAM on APD and IKSS showing that both EPAC isoforms are involved in these effects. Unexpectedly, calmodulin-dependent protein kinase II (CaMKII) inhibition by AIP or KN-93, and Ca2+ chelation by intracellular BAPTA, did not impact the response to 8-CPTAM. However, inhibition of PLC/PKC and nitric oxide synthase (NOS)/PKG pathways partially prevents the 8-CPTAM-dependent decrease of IKSS. Finally, the cumulative inhibition of PKC and PKG blocked the 8-CPTAM effect, suggesting that these two actors work along parallel pathways to regulate IKSS upon EPAC activation. On the basis of such findings, we propose that EPAC1 and EPAC2 are involved in APD lengthening by inhibiting a K+ current via both PLC/PKC and NOS/PKG pathways. This may have pathological implications since EPAC is upregulated in diseases such as cardiac hypertrophy.NEW & NOTEWORHTY Exchange protein directly activated by cAMP (EPAC) proteins modulate ventricular electrophysiology at the cellular level. Both EPAC1 and EPAC2 isoforms participate in this effect. Mechanistically, PLC/PKC and nitric oxide synthase (NO)/PKG pathways are involved in regulating K+ repolarizing current whereas the well-known downstream effector of EPAC, calmodulin-dependent protein kinase II (CaMKII), does not participate. This may have pathological implications since EPAC is upregulated in diseases such as cardiac hypertrophy. Thus, EPAC inhibition may be a new approach to prevent arrhythmias under pathological conditions.
Assuntos
Potenciais de Ação , Fatores de Troca do Nucleotídeo Guanina , Ventrículos do Coração , Miócitos Cardíacos , Proteína Quinase C , Transdução de Sinais , Animais , Fatores de Troca do Nucleotídeo Guanina/metabolismo , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/enzimologia , Proteína Quinase C/metabolismo , Ratos , Potenciais de Ação/efeitos dos fármacos , Ventrículos do Coração/metabolismo , Ventrículos do Coração/citologia , Proteínas Quinases Dependentes de GMP Cíclico/metabolismo , Óxido Nítrico Sintase/metabolismo , Óxido Nítrico Sintase/antagonistas & inibidores , Fosfolipases Tipo C/metabolismo , Fosfolipases Tipo C/antagonistas & inibidores , Masculino , Ratos Wistar , Potássio/metabolismo , AMP Cíclico/metabolismoRESUMO
Nitric oxide (NO) is a gaseous molecule that regulates various reproductive functions. It is a well-recognized regulator of GnRH-FSH/LH-sex steroid secretion in vertebrates including fish. Kisspeptin is a recently discovered neuropeptide which also regulates GnRH secretion. Nitrergic and kisspeptin neurons are reported in close physical contact in the mammalian brain suggesting their interactive role in the release of GnRH. The existence of kisspeptin and NOS is also demonstrated in vertebrate gonads, but information on their reciprocal relation in gonads, if any, is obscure. Therefore, attempts were made to evaluate the functional reciprocal relation between nitric oxide and kisspeptin in the catfish gonads, if any, by administering the nitric oxide synthase (NOS) inhibitor, L-NAME {N(G)-nitro-L-arginine methyl ester}, which reduces NO production, and kisspeptin agonist (KP-10) and assessing their impacts on the expressions of kisspeptin1, different NOS isoforms, NO and steroid production in the gonadal tissue. The results revealed that L-NAME suppressed the expression of kiss1 in gonads of the catfish establishing the role of NO in kisspeptin expression. However, KP-10 increased the expression of all the isoforms of NOSs (iNOS, eNOS, nNOS) and concurrently NO and steroids in the ovary and testis. In vitro studies also indicate that kisspeptin stimulates the production of NO and estradiol and testosterone levels in the gonadal explants and medium. Thus, in vivo results clearly suggest a reciprocal interaction between kisspeptin and NO to regulate the gonadal activity of the catfish. The in vitro findings further substantiate our contention regarding the interactive role of kisspeptin and NO in gonadal steroidogenesis.
Assuntos
Peixes-Gato , Gametogênese , Kisspeptinas , NG-Nitroarginina Metil Éster , Óxido Nítrico , Animais , Óxido Nítrico/metabolismo , Peixes-Gato/metabolismo , Kisspeptinas/metabolismo , Masculino , NG-Nitroarginina Metil Éster/farmacologia , Feminino , Gametogênese/efeitos dos fármacos , Esteroides/biossíntese , Óxido Nítrico Sintase/metabolismo , Testículo/metabolismo , Testículo/efeitos dos fármacos , Gônadas/metabolismo , Gônadas/efeitos dos fármacos , Ovário/metabolismoRESUMO
Nitric oxide (NO) is a key diffusible messenger in the mammalian brain. It has been proposed that NO may diffuse retrogradely into presynaptic terminals, contributing to the induction of hippocampal long-term potentiation (LTP). Here, we present novel evidence that NO is required for kainate receptor (KAR)-dependent presynaptic form of LTP (pre-LTP) in the adult insular cortex (IC). In the IC, we found that inhibition of NO synthase erased the maintenance of pre-LTP, while the induction of pre-LTP required the activation of KAR. Furthermore, NO is essential for pre-LTP induced between two pyramidal cells in the IC using the double patch-clamp recording. These results suggest that NO is required for homosynaptic pre-LTP in the IC. Our results present strong evidence for the critical roles of NO in pre-LTP in the IC. This article is part of a discussion meeting issue 'Long-term potentiation: 50 years on'.
Assuntos
Córtex Cerebral , Potenciação de Longa Duração , Óxido Nítrico , Terminações Pré-Sinápticas , Potenciação de Longa Duração/fisiologia , Óxido Nítrico/metabolismo , Animais , Córtex Cerebral/fisiologia , Terminações Pré-Sinápticas/fisiologia , Receptores de Ácido Caínico/metabolismo , Técnicas de Patch-Clamp , Ratos , Células Piramidais/fisiologia , Óxido Nítrico Sintase/metabolismo , CamundongosRESUMO
BACKGROUND: It has been previously demonstrated that the maintenance of ischemic acidic pH or the delay of intracellular pH recovery at the onset of reperfusion decreases ischemic-induced cardiomyocyte death. OBJECTIVE: To examine the role played by nitric oxide synthase (NOS)/NO-dependent pathways in the effects of acidic reperfusion in a regional ischemia model. METHODS: Isolated rat hearts perfused by Langendorff technique were submitted to 40 min of left coronary artery occlusion followed by 60 min of reperfusion (IC). A group of hearts received an acid solution (pH = 6.4) during the first 2 min of reperfusion (AR) in absence or in presence of l-NAME (NOS inhibitor). Infarct size (IS) and myocardial function were determined. In cardiac homogenates, the expression of P-Akt, P-endothelial and inducible isoforms of NOS (P-eNOS and iNOS) and the level of 3-nitrotyrosine were measured. In isolated cardiomyocytes, the intracellular NO production was assessed by confocal microscopy, under control and acidic conditions. Mitochondrial swelling after Ca2+ addition and mitochondrial membrane potential (Δψ) were also determined under control and acidosis. RESULTS: AR decreased IS, improved postischemic myocardial function recovery, increased P-Akt and P-eNOS, and decreased iNOS and 3-nitrotyrosine. NO production increased while mitochondrial swelling and Δψ decreased in acidic conditions. l-NAME prevented the beneficial effects of AR. CONCLUSIONS: Our data strongly supports that a brief acidic reperfusion protects the myocardium against the ischemia-reperfusion injury through eNOS/NO-dependent pathways.