RESUMEN
The role of nitrergic system in modulating the action of psychostimulants on reward processing is well established. However, the relevant anatomical underpinnings and scope of the involved interactions with mesolimbic dopaminergic system have not been clarified. Using immunohistochemistry, we track the changes in neuronal nitric oxide synthase (nNOS) containing cell groups in the animals conditioned to intracranial self-stimulation (ICSS) via an electrode implanted in the lateral hypothalamus-medial forebrain bundle (LH-MFB) area. An increase in the nNOS immunoreactivity was noticed in the cells and fibers in the ventral tegmental area (VTA) and nucleus accumbens shell (AcbSh), the primary loci of the reward system. In addition, nNOS was up-regulated in the nucleus accumbens core (AcbC), vertical limb of diagonal band (VDB), locus coeruleus (LC), lateral hypothalamus (LH), superficial gray layer (SuG) of the superior colliculus, and periaqueductal gray (PAG). The brain tissue fragments drawn from these areas showed a change in nNOS mRNA expression, but in opposite direction. Intracerebroventricular (icv) administration of nNOS inhibitor, 7-nitroindazole (7-NI) showed decreased lever press activity in a dose-dependent manner in ICSS task. While an increase in the dopamine (DA) and 3, 4-dihydroxyphenylacetic acid (DOPAC) efflux was noted in the microdialysates collected from the AcbSh of ICSS rats, pre-administration of 7-NI (icv route) attenuated the response. The study identifies nitrergic centers that probably mediate sensory, cognitive, and motor components of the goal-directed behavior.
Asunto(s)
Óxido Nítrico Sintasa de Tipo I , Autoestimulación , Animales , Masculino , Ratas , Óxido Nítrico Sintasa de Tipo I/metabolismo , Encéfalo/metabolismo , Encéfalo/efectos de los fármacos , Ratas Sprague-Dawley , Indazoles/farmacología , Inhibidores Enzimáticos/farmacologíaRESUMEN
Sepsis is a life-threatening condition caused by a dysregulated host response to infection. The development of sepsis is associated with excessive nitric oxide (NO) production, which plays an important role in controlling vascular homeostasis. 7-nitroindazole (7-NI) is a selective inhibitor of neuronal nitric oxide synthase (NOS-1) with potential application for treating NO imbalance conditions. However, 7-NI exhibits a low aqueous solubility and a short plasma half-life. To circumvent these biopharmaceutical limitations, pegylated (NEPEG7NI) and non-pegylated nanoemulsions (NENPEG7NI) containing 7-NI were developed. This study evaluates the pharmacokinetic profiles and toxicological properties of 7-NI loaded into the nanoemulsions. After a single intravenous administration of the free drug and the nanoemulsions at a dose of 10 mg.kg-1 in Wistar rats, 7-NI was widely distributed in the organs. The pharmacokinetic parameters of Cmax, t1/2, and AUC0-t were significantly increased after administration of the NEPEG7NI, compared to both free 7-NI and NENPEG7NI (p < 0.05). No observable adverse effects were observed after administering the free 7-NI, NEPEG7NI, or NENPEG7NI in the animals after a single dose of up to 3.0 mg.kg-1. The results indicated that 7-NI-loaded nanoemulsions are safe, constituting a promising approach to treating sepsis.
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Óxido Nítrico Sintasa , Sepsis , Ratas , Animales , Ratas Wistar , Óxido Nítrico Sintasa/metabolismo , Distribución Tisular , Indazoles/toxicidad , Indazoles/farmacocinética , Polietilenglicoles/toxicidad , Inhibidores Enzimáticos/farmacologíaRESUMEN
Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by behavioral deficits such as abnormalities in communication, social interaction, anxiety, and repetitive behavior. We have recently shown that the Shank3 mutation in mice representing a model of ASD causes excessive nitric oxide (NO) levels and aberrant protein S-nitrosylation. Further, 10-day daily injections of 7-NI, a neuronal nitric oxide synthase inhibitor, into Shank3Δ4-22 and Cntnap2(-/-) mutant mice (models of ASD) at a dose of 80 mg/kg reversed the manifestations of ASD phenotype. In this study, we proposed an extended release of 7-NI using a novel drug system. Importantly, unlike the intraperitoneal injections, our new preparation of poly (sebacic acid-co-ricinoleic acid) (PSARA) gel containing 7-NI was injected subcutaneously into the mutant mice only once. The animals underwent behavioral testing starting from day 3 post-injection. It should be noted that the developed PSARA gel formulation allowed a slow release of 7-NI maintaining the plasma level of the drug at â¼45 µg/ml/day. Further, we observed improved memory and social interaction and reduced anxiety-like behavior in Shank3 mutant mice. This was accompanied by a reduction in 3-nitrotyrosine levels (an indicator of nitrative/nitrosative stress) in plasma. Overall, we suggest that our single-dose formulation of PSARA gel is very efficient in rendering a therapeutic effect of 7-NI for at least 10 days. This approach may provide in the future a rational design of an effective ASD treatment using 7-NI and its clinical translation.
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Trastorno del Espectro Autista , Trastorno Autístico , Ratones , Animales , Trastorno Autístico/genética , Trastorno del Espectro Autista/tratamiento farmacológico , Trastorno del Espectro Autista/genética , Trastorno del Espectro Autista/metabolismo , Indazoles , Conducta Animal , Modelos Animales de Enfermedad , Proteínas de Microfilamentos , Proteínas del Tejido NerviosoRESUMEN
Mephedrone, a popular psychostimulating substance widely used illegally in recreational purposes, exerts in rodents that regularly and intermittently were exposed to it a sensitized response to the drug. Behavioral sensitization is one of experimental models of drug dependency/abuse liability. In the present study we evaluated a potential involvement of the L-arginine-NO-cGMP pathway in the development of sensitization to the mephedrone-induced hyperlocomotion. Locomotor activity was measured automatically and experiments were performed on male Albino Swiss mice. We demonstrated that a 5-day administration of 7-nitroindazole (10 or 20 mg/kg/day) and L-NAME (50 mg/kg/day) suppressed the development of sensitization to the mephedrone-induced hyperlocomotion. As for L-arginine (125 or 250 mg/kg/day) and methylene blue (5 or 10 mg/kg/day) the obtained outcomes are inconclusive. Furthermore, the lower dose of L-NAME (25 mg/kg/day) surprisingly potentiated the development of sensitization to the mephedrone-induced effects on the spontaneous locomotor activity in mice. In conclusion, our data demonstrated that modulators of the L-arginine-NO-cGMP pathway may differently affect the development of sensitization to the locomotor stimulant effects of mephedrone. Inhibition of neuronal nitric oxide synthase (NOS) seems to prevent this process quite profoundly, non-selective inhibition of NOS may have a dual effect, whereas inhibition of soluble guanylate cyclase may only partially suppress the development of sensitization to the mephedrone-induced effects.
Asunto(s)
GMP Cíclico , Óxido Nítrico , Animales , Ratones , Masculino , NG-Nitroarginina Metil Éster/farmacología , Óxido Nítrico/metabolismo , GMP Cíclico/metabolismo , Arginina/farmacología , Arginina/metabolismo , Locomoción , Relación Dosis-Respuesta a DrogaRESUMEN
While SSRIs are the current first-line pharmacotherapies against post-traumatic stress disorder (PTSD), they suffer from delayed onset of efficacy and low remission rates. One solution is to combine SSRIs with other treatments. Neuronal nitric oxide synthase (nNOS) has been shown to play a role in serotonergic signaling, and there is evidence of synergism between nNOS modulation and SSRIs in models of other psychiatric conditions. Therefore, in this study, we combined subchronic fluoxetine (Flx) with 7-nitroindazole (NI), a selective nNOS inhibitor, and evaluated their efficacy against anxiety-related behavior in an animal model of PTSD. We used the underwater trauma model to induce PTSD in rats. Animals underwent the open field (OFT) and elevated plus maze tests on days 14 (baseline) and 21 (post-treatment) after PTSD induction to assess anxiety-related behaviors. Between the two tests, the rats received daily intraperitoneal injections of 10 mg/kg Flx or saline, and were injected intraperitoneally before the second test with either 15 mg/kg NI or saline. The change in behaviors between the two tests was compared between treatment groups. Individual treatment with both Flx and NI had anxiogenic effects in the OFT. These effects were associated with modest increases in cFOS expression in the hippocampus. Combination therapy with Flx + NI did not show any anxiogenic effects, while causing even higher expression levels of cFOS. In conclusion, addition of NI treatment to subchronic Flx therapy accelerated the abrogation of Flx's anxiogenic properties. Furthermore, hippocampal activity, as evidenced by cFOS expression, was biphasically related to anxiety-related behavior.
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Ansiolíticos , Inhibidores Enzimáticos , Óxido Nítrico Sintasa de Tipo I , Inhibidores Selectivos de la Recaptación de Serotonina , Trastornos por Estrés Postraumático , Animales , Ratas , Ansiedad/metabolismo , Modelos Animales de Enfermedad , Fluoxetina/farmacología , Fluoxetina/uso terapéutico , Hipocampo/metabolismo , Óxido Nítrico/metabolismo , Óxido Nítrico Sintasa de Tipo I/antagonistas & inhibidores , Óxido Nítrico Sintasa de Tipo I/metabolismo , Inhibidores Selectivos de la Recaptación de Serotonina/farmacología , Inhibidores Selectivos de la Recaptación de Serotonina/uso terapéutico , Trastornos por Estrés Postraumático/tratamiento farmacológico , Trastornos por Estrés Postraumático/metabolismo , Quimioterapia Combinada , Inhibidores Enzimáticos/farmacología , Inhibidores Enzimáticos/uso terapéutico , Ansiolíticos/farmacología , Ansiolíticos/uso terapéuticoRESUMEN
BACKGROUND AND AIM: Echinodorus macrophyllus (Kunth.) Micheli is popularly used for acute and chronic inflammatory conditions. The anti-inflammatory activity was previously demonstrated for its flavonoid-enriched fractions. The aim of this work assessed the antinociceptive properties of both aqueous extract and its fractions. EXPERIMENTAL PROCEDURE: The antinociceptive activity was determined by acetic acid-induced writhing, formalin test, tail immersion test, hot-plate test, xylene-induced ear edema methods, and the evaluation of its mechanism was performed in the writhing model. The aqueous extract of Echinodorus macrophyllus (AEEm) was fractionated, yielding Fr20, and Fr40. Fr40 composition was determined by HPLC-DAD-ESI-MS. RESULTS AND CONCLUSION: Fr20 (all doses) and Fr40 (100 mg/kg) reduced the nociception in the tail-flick model. Both fractions increased the percentage of maximum possible effect with 25 mg/kg, in the hot-plate assay, at 60 min, while AEEm reduced pain only with 50 and 100 mg/kg. There was a reduction in xylene-edema index, with Fr40 (25 mg/kg), AEEm (50 mg/kg) and Fr20 (50 mg/kg). All doses of AEEm, Fr20, and Fr40 reduced both phases of the formalin model. In the abdominal contortion model, Fr40 presented the highest activity, reducing 96% of contortions and its antinociceptive mechanism was evaluated. The results indicated the involvement of NO and adrenergic activation pathways. The main components of Fr40 are swertisin, swertiajaponin, isoorientin 7,3'-dimethyl ether, swertisin-O-rhamnoside, isoorientin, isovitexin, isovitexin-Orhamnoside, and isovitexin-7-O-glucoside. The aqueous extract of E. macrophyllus leaves and its fractions exhibited significant analgesic effect, mediated through both peripheral and central mechanisms being considered a potentially antinociceptive drug.
RESUMEN
Epilepsy is identified as a brain disorder and characterized by unpredictable disruption of normal brain function. Due to adverse side effect associated with antiepileptic drugs and also resistance profile, improvement of antiepileptic medications with more beneficial anticonvulsant activity is essential. Natural products have demonstrated their therapeutic properties such as anxiolytic, antidepressant and anticonvulsant activities and a source for identification of novel lead compounds. Therefore, the purpose of this study was to evaluate the effects of Onopordon acanthium secondary metabolite, onopordia, on pentylenetetrazole (PTZ)-induced seizure in male mice and investigate the possible role of nitric oxide pathway. Different doses of onopordia (0.1, 1 and 10 mg/kg) and phenobarbital (20 mg/kg) were administered intraperitoneally (i.p., 30, 60 and 120 min) prior to induction of epileptic seizure and compared to control groups. Onopordia demonstrated anticonvulsant effects when administrated at dose of 10 mg/kg, i.p. and optimum time 60 min prior to induction of seizure. Anticonvulsant effect of onopordia was blocked by applying a single dose of a non-selective nitric oxide synthase (NOS) inhibitor, Nω-nitro-l-arginine methyl ester hydrochloride (l-NAME; 10 mg/kg, i.p.), and also a single dose of a selective neuronal NOS (nNOS) inhibitor, 7-nitroindazole (7-NI; 30 mg/kg, i.p.). Administration of ketamine as a N-Methyl-d-aspartic acid (NMDA) receptor antagonist (0.5 mg/kg; i.p.) with onopordia did not change the anticonvulsant effect of onopordia. The results of the present study demonstrated the anticonvulsant effect of onopordia as a new lead compound and also contribution of NO/nNOS pathway on PTZ-induced seizure in mice.
RESUMEN
Nitric oxide (NO) is known to be a neuromodulator with dual proconvulsive and anticonvul- sive action. Valeriana officinalis (VAL) was previously believed to be antiepileptic, but is today known as a sedative and sleep regulator. Seizures may be associated with abnormal electrocardio- graphic changes and cardiac dysfunction arising from epilepsy may be related with neuronal nitric oxide (nNO). This study was aimed to investigate the effects of the neuronal nitric oxide synthase (nNOS) inhibitor 7-Nitroindazole (7-NI) and VAL on seizure behaviours and electrocar- diographic parameters in the pentylentetrazole (PTZ)-kindled seizure model. Wistar rats were randomised into saline control, PTZ-kindled, 7-NI, VAL and VAL+PTZ, 7-NI+PTZ and VAL+7-NI+PTZ groups. Latency, stage, frequency of seizures, blood pressure (BP), heart rate (HR) and corrected QT (QTc) values were evaluated. Frequency and stage of seizures, BP and HR increased, while seizure latency decreased and QTc was prolonged in the PTZ-kindled group. 7-NI and VAL had no effects on BP and HR variables under normal conditions, but ameliorated the seizure stage and frequency of seizures. 7-NI treatment also resulted in a reduction of the increased BP and prolonged QTc values observed in PTZ-kindled rats. Considering these results, QTc prolongation may be used as a predictor for recurrent seizures. 7-NI and VAL exhibited different effects on seizures and ECG variables. 7-NI shows potential as an anticonvulsant drug agent in epileptic patients with cardiac dysfunctions and those additional studies including in-vivo experiments are essential.
Asunto(s)
Presión Sanguínea/efectos de los fármacos , Electrocardiografía/efectos de los fármacos , Indazoles/farmacología , Pentilenotetrazol/toxicidad , Extractos Vegetales/farmacología , Valeriana/química , Animales , Anticonvulsivantes/química , Anticonvulsivantes/farmacología , Convulsivantes/toxicidad , Masculino , Extractos Vegetales/química , Distribución Aleatoria , RatasRESUMEN
Hypothyroidism-associated learning and memory impairment is reported to be connected to oxidative stress and reduced levels of brain-derived neurotrophic factor (BDNF). The effects of neuronal nitric oxide inhibitor 7-nitroindazole (7NI) on brain tissues oxidative damage, nitric oxide (NO), BDNF and memory impairments in hypothyroid juvenile rats were investigated. Male Wistar juvenile rats (20 days old) were divided into five groups, including Martinez et al. (J Neurochem 78 (5):1054-1063, 2001). Control in which vehicle was injected instead of 7NI, (Jackson in Thyroid 8 (10):951-956, 1998) Propylthiouracil (PTU) where 0.05% PTU was added in drinking water and vehicle was injected instead of 7NI, (Gong et al. in BMC Neurosci 11 (1):50, 2010; Alva-Sánchez et al. in Brain Res 1271:27-35, 2009; Anaeigoudari et al. in Pharmacol Rep 68 (2): 243-249, 2016) PTU-7NI 5, PTU-7NI 10 and PTU-7NI 20 in which 5, 10, or 20 mg/kg7NI was injected intraperitoneally (i.p.). Following 6 weeks, Morris water maze (MMW) and passive avoidance learning (PAL) tests were used to evaluate the memory. Finally, the hippocampus and the cortex of the rats were removed after anesthesia by urethane to be used for future analysis. The escape latency and traveled path in MWM test was increased in PTU group (P < 0.001). PTU also reduced the latency to enter the dark box of PAL and the time spent and the distance in the target quadrant in MWM test (P < 0.001 and P < 0.01). Treatment with 7NI attenuated all adverse effects of PTU (P < 0.05 to P < 0.001). PTU lowered BDNF and thiol content and superoxide dismutase (SOD) and catalase (CAT) activities in the brain but increased malondialdehyde (MDA) and nitric oxide (NO) metabolites. In addition, 7NI improved thiol, SOD, CAT, thiol, and BDNF but attenuated MDA and NO metabolites. The results of the current study showed that 7NI improvement in the learning and memory of the hypothyroid juvenile rats, which was accompanied with improving of BDNF and attenuation of NO and brain tissues oxidative damage.
Asunto(s)
Factor Neurotrófico Derivado del Encéfalo/metabolismo , Hipotiroidismo/metabolismo , Indazoles/uso terapéutico , Discapacidades para el Aprendizaje/tratamiento farmacológico , Trastornos de la Memoria/tratamiento farmacológico , Óxido Nítrico Sintasa de Tipo I/antagonistas & inhibidores , Animales , Inhibidores Enzimáticos/uso terapéutico , Hipocampo/efectos de los fármacos , Hipotiroidismo/inducido químicamente , Hipotiroidismo/complicaciones , Discapacidades para el Aprendizaje/etiología , Masculino , Aprendizaje por Laberinto/efectos de los fármacos , Memoria/efectos de los fármacos , Trastornos de la Memoria/etiología , Prueba del Laberinto Acuático de Morris/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos , Propiltiouracilo , Ratas WistarRESUMEN
MDMA abuse continues being a serious problem in our society. Environmental factors, such as stress, increase the vulnerability of individuals to develop drug abuse and we have observed that exposure to social defeat (SD) stress alters the sensitivity of mice to the rewarding effects of MDMA in the conditioned place preference (CPP) paradigm. In the present study, we evaluated the role of the nitric oxide (NO) pathway in the effects of SD on the rewarding properties of MDMA. Three groups of mice were treated with an inhibitor of NO synthesis, 7-nitroindazole (0, 7.25 and 12.5 mg/kg), before each exposure to SD and place conditioning with MDMA (1.25 mg/kg) on PND 54, 56, 58, and 60. One control group was not exposed to SD before place conditioning. In addition, we studied the effects of SD on the levels of nitrites in the striatum, hippocampus and frontal cortex. Our results showed that the low dose of 7-nitroindazole blocked the effects of SD on the rewarding properties of MDMA. Moreover, SD exposure increased the nitrites in the prefrontal cortex and hippocampus. These results demonstrated the role of NO signalling in the effects of SD stress in mice and suggested that the inhibition of NO synthesis may confer resilience to the effects of social stress on the rewarding properties of MDMA. The manipulation of the NO signalling pathway could be a useful target for the treatment of MDMA-dependent subjects who experienced high levels of stress.
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Condicionamiento Psicológico/efectos de los fármacos , Indazoles/farmacología , N-Metil-3,4-metilenodioxianfetamina/antagonistas & inhibidores , Óxido Nítrico/antagonistas & inhibidores , Animales , Relación Dosis-Respuesta a Droga , Masculino , Ratones , Ratones Endogámicos , N-Metil-3,4-metilenodioxianfetamina/administración & dosificación , N-Metil-3,4-metilenodioxianfetamina/farmacología , Óxido Nítrico/análisis , Óxido Nítrico/metabolismo , Transducción de Señal/efectos de los fármacos , Estrés PsicológicoRESUMEN
Inhibition of nitric oxide (NO) production can influence blood pressure regulation and increase hypertension. Asymmetric dimethylarginine, ADMA, an analogue of L-arginine, can inhibit NO synthesis, impair endothelial function, and is a risk marker of cardiovascular diseases. Homocysteine (Hcy) level affects oxidative stress production of reactive oxygen species (ROS) in hypertension and also influences changes in signaling and cell damage. The present study was focused on experimental effects of exogenous NOS inhibitors and their effect on ADMA, an endogenous NOS inhibitor, homocysteine and ROS production measured as reactive oxidative metabolites (ROM). We compared effects of the two potential exogenous NO-inhibitors: NG-nitro L-arginine methyl ester (L-NAME) and 7-nitroindazole (7-NI). Levels of ADMA, Hcy, ROM and total thiols (TTL) were not changed in the L-NAME group. With 7-NI administration, we observed unchanged NOS activity in the left ventricle and a pronounced decrease of ADMA and Hcy levels, accompanied by ROM over-production in plasma. TTL/ROM ratio was more favorable than in the L-NAME group. We observed that 7-NI, an exogenous NOinhibitor, can decrease and improve the levels of ADMA, Hcy, and ROM, and increase TTL/ROM ratio in the plasma of spontaneously hypertensive rats.
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Arginina/análogos & derivados , Inhibidores Enzimáticos/farmacología , Homocisteína/sangre , Hipertensión/enzimología , Indazoles/farmacología , Óxido Nítrico Sintasa/antagonistas & inhibidores , Animales , Aorta/efectos de los fármacos , Aorta/enzimología , Aorta/fisiopatología , Arginina/sangre , Biomarcadores/sangre , Modelos Animales de Enfermedad , Ventrículos Cardíacos/efectos de los fármacos , Ventrículos Cardíacos/enzimología , Ventrículos Cardíacos/fisiopatología , Hipertensión/sangre , Hipertensión/fisiopatología , NG-Nitroarginina Metil Éster/farmacología , Óxido Nítrico Sintasa/metabolismo , Oxidación-Reducción , Ratas Endogámicas SHRRESUMEN
RATIONALE: There is evidence that central mu opioid receptors (MORs) are implicated in several aspects of cocaine addiction, and that MOR expression is elevated by cocaine in vitro and in the nucleus accumbens (NAc) when administered in vivo. OBJECTIVE: To understand the cellular mechanisms involved in regulating MOR expression, this study explored whether neuronal nitric oxide synthase (nNOS) modulates the neurochemical and behavioral effects of acute and repeated cocaine administration. METHODS: Male Sprague-Dawley rats received a single cocaine injection (20 mg/kg, i.p.) in combination with the selective nNOS inhibitor 7-nitroindazole (7-NI) (0, 25, or 50 mg/kg, i.p.), and the expression of MOR and nNOS messenger RNA (mRNA) and protein levels in the NAc were measured. In a separate conditioned place preference (CPP) experiment, 7-NI (0, 25, or 50 mg/kg, i.p.) was administered prior to cocaine (0 or 20 mg/kg, i.p.) conditioning sessions, and levels of MOR and nNOS mRNA and protein in the NAc were measured following CPP test. RESULTS: Acute cocaine administration significantly enhanced nNOS and MOR mRNA and protein expression in the NAc, and this increase in MOR expression was blocked by 7-NI. Furthermore, in 7-NI pre-treated rats, cocaine-induced CPP was not statistically significant and the increase in MOR mRNA expression in the NAc in these animals was attenuated. CONCLUSIONS: These findings suggest that nNOS modulates MOR expression following acute cocaine administration, and that cocaine CPP and associated upregulation of MOR expression involve both nNOS-dependent and independent mechanisms. Elucidation of these molecular events may identify useful therapeutic target for cocaine addiction.
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Trastornos Relacionados con Cocaína/metabolismo , Cocaína/farmacología , Condicionamiento Clásico/efectos de los fármacos , Óxido Nítrico Sintasa de Tipo I/fisiología , Núcleo Accumbens/metabolismo , Receptores Opioides mu/metabolismo , Análisis de Varianza , Animales , Modelos Animales de Enfermedad , Masculino , Óxido Nítrico Sintasa de Tipo I/metabolismo , Núcleo Accumbens/efectos de los fármacos , Ratas , Ratas Sprague-DawleyRESUMEN
PURPOSE: Experiments have shown that hyperbaric oxygen (HBO2) therapy reduces cyanide-induced cerebral distress. The exact mechanism behind HBO2's neuroprotective effect is unknown, but has been proposed to be mediated by an increased neuronal nitric oxide (NO) bioavailability, which may compete with cyanide for the active site of cytochrome oxidase in the mitochondrial respiratory chain. We hypothesized that the ameliorating effect of HBO2 is caused by an increased bioavailability of NO, which can be attenuated by injection of the selective neuronal NO synthase inhibitor, 7-nitroindazole, preceding the HBO2 procedure. METHODS: A total of 41 anesthetized female Sprague-Dawley rats were allocated to four groups: 1) vehicle [1.2 ml isotonic NaCl via intra-arterial administration]; 2) cyanide [5.4 mg/kg potassium CN (KCN) intra-arterial] plus 7-nitroindazole [25 mg/kg 7-nitroindazole via intraperitoneal injection]; 3) cyanide plus 7-nitroindazole plus HBO2 [284 kPa for 90 minutes]; 4) cyanide plus 7-nitroindazole plus normobaric oxygen [101.3 kPa for 90 minutes]. Cerebral interstitial lactate, glucose, glycerol and pyruvate were evaluated by means of microdialysis. RESULTS: HBO2 during inhibition of nNOS worsened cerebral metabolism compared to both solely CN-intoxicated animals and normobaric oxygen-treated animals. This was indicated by elevated lactate (in mM; 0.85 vs. 0.63 and 0.42, P=0.006 and P ⟨ 0.001, respectively), glycerol (in mM; 46 vs. 17 and 14, both P ⟨ 0.001), glucose (in mM; 0.58 vs. 0.31 and 0.32, both P ⟨ 0.001). CONCLUSIONS: The results indicate that a specific nNOS inhibition offsets the ameliorating effect of HBO2 during cerebral CN intoxication. However, other factors might contribute to this neuroprotective effect as well.
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Encefalopatías/metabolismo , Encéfalo/metabolismo , Cianuros/envenenamiento , Oxigenoterapia Hiperbárica , Óxido Nítrico Sintasa de Tipo I/antagonistas & inhibidores , Animales , Encefalopatías/inducido químicamente , Encefalopatías/terapia , Inhibidores Enzimáticos/farmacología , Femenino , Glucosa/metabolismo , Glicerol/metabolismo , Indazoles/farmacología , Ácido Láctico/metabolismo , Óxido Nítrico Sintasa de Tipo I/metabolismo , Oxígeno/administración & dosificación , Oxígeno/metabolismo , Presión Parcial , Ácido Pirúvico/metabolismo , Ratas , Ratas Sprague-DawleyRESUMEN
Neuronal nitric oxide synthase (nNOS) is involved in nigrostriatal dopaminergic (DA) neurodegeneration. However, little is known about the distribution patterns and functions of nNOS in slowly progressive DA neurodegeneration. Here we describe the spatiotemporal change in nNOS expression over the course of neurodegeneration and the effect of short- or long-term treatment with the nNOS inhibitor, 7-nitroindazole (7-NI), in zitter (zi/zi) rats. In the substantia nigra pars compacta (SNc), nNOS expression was significantly increased with progression of neurodegeneration. nNOS-immunoreactive (ir) cells were in the vicinity of tyrosine hydroxylase-ir (TH-ir) DA neurons, and some of these cells were also positive for calbindin. nNOS in the caudate-putamen (CPu) showed little difference during progression of neurodegeneration. However, immunoelectron microscopic analysis revealed that abundant TH-ir fibers in the CPu were degenerated due to compression by vacuoles that contained swollen neuronal and glial elements. Additionally, lipid peroxidation as a marker of membrane oxidation was significantly increased in zi/zi rats. Short-term 7-NI treatment attenuated the increase in lipid peroxidation and inhibited the vacuolation in the CPu. Moreover, long-term 7-NI treatment significantly protected TH-ir neurons in the SNc, and TH-ir fibers and DA contents in the CPu. These results show that nNOS exacerbates slowly progressive DA neurodegeneration, and the neuroprotective effects of 7-NI may result from suppression of membrane oxidation that causes abnormal membrane structures in zi/zi rats.
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Neuronas Dopaminérgicas/patología , Neuronas Dopaminérgicas/fisiología , Degeneración Nerviosa/fisiopatología , Óxido Nítrico Sintasa de Tipo I/metabolismo , Ácido 3,4-Dihidroxifenilacético/metabolismo , Animales , Secuencia de Bases , Núcleo Caudado/efectos de los fármacos , Núcleo Caudado/metabolismo , Núcleo Caudado/patología , Dopamina/metabolismo , Neuronas Dopaminérgicas/efectos de los fármacos , Inhibidores Enzimáticos/farmacología , Indazoles/farmacología , Peroxidación de Lípido/fisiología , Masculino , Proteínas de la Membrana/genética , Degeneración Nerviosa/tratamiento farmacológico , Fármacos Neuroprotectores/farmacología , Óxido Nítrico Sintasa de Tipo I/antagonistas & inhibidores , Óxido Nítrico Sintasa de Tipo I/genética , Porción Compacta de la Sustancia Negra/efectos de los fármacos , Porción Compacta de la Sustancia Negra/metabolismo , Porción Compacta de la Sustancia Negra/patología , Putamen/efectos de los fármacos , Putamen/metabolismo , Putamen/patología , ARN Mensajero/metabolismo , Ratas , Eliminación de Secuencia , Vacuolas/metabolismoRESUMEN
BACKGROUND: Nitric oxide synthase (NOS) inhibitors induce antidepressant-like effects in animal models sensitive to acute drug treatment such as the forced swimming test. However, it is not yet clear if repeated treatment with these drugs is required to induce antidepressant-like effects in preclinical models. OBJECTIVE: The aim of this study was to test the effect induced by acute or repeated (7 days) treatment with 7-nitroindazole (7-NI), a preferential inhibitor of neuronal NOS, in rats submitted to the learned helplessness (LH) model. In addition, we aimed at investigating if 7-NI treatment would increase brain-derived neurotrophic factor (BDNF) protein levels in the hippocampus, similarly to the effect of prototype antidepressants. METHODS: Animals were submitted to a pre-test (PT) session with inescapable footshocks or habituation (no shocks) to the experimental shuttle box. Six days later they were exposed to a test with escapable footshocks. Independent groups received acute (a single injection after PT or before test) or repeated (once a day for 7 days) treatment with vehicle or 7-NI (30 mg/kg). RESULTS: Repeated, but not acute, treatment with 7-NI attenuated LH development. The effect was similar to repeated imipramine treatment. Moreover, in an independent experimental group, only repeated treatment with 7-NI and imipramine increased BDNF protein levels in the hippocampus. CONCLUSION: The results suggest the nitrergic system could be a target for the treatment of depressive-like conditions. They also indicate that, similar to the positive control imipramine, the antidepressant-like effects of NOS inhibition could involve an increase in hippocampal BDNF levels.
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Antidepresivos Tricíclicos/farmacología , Conducta Animal/efectos de los fármacos , Factor Neurotrófico Derivado del Encéfalo/efectos de los fármacos , Depresión/tratamiento farmacológico , Inhibidores Enzimáticos/farmacología , Desamparo Adquirido , Hipocampo/efectos de los fármacos , Óxido Nítrico Sintasa/antagonistas & inhibidores , Animales , Antidepresivos Tricíclicos/administración & dosificación , Modelos Animales de Enfermedad , Inhibidores Enzimáticos/administración & dosificación , Imipramina/farmacología , Indazoles/farmacología , RatasRESUMEN
Objective To evaluate the effect of intracerebroventricular injection of 7-nitroindazole (7-NI) on the depression-like behaviors in normal rats.Methods According to body weights,48 SD rats were randomly divided into normal group,model group,sham-operation group and 7-NI groups at different concentrations (n=8).The model group was treated with chronic and unpredictable mild stress.The 7-NI groups received intracerebroventricular injection with 7-NI solutions at different concentrations,once every 3 days for 3 times in total.The sham-operation group was injected with DMSO of the same volume.The rat behaviors were then subjected to the open field test (OFT).The hippocampal nNOS protein levels were detected by Western blot.Results Compared with the normal group((132.47±31.72) m),the total movement distances of model group ((15.04±8.61) m) and 200 nmol/0.5 μl surgery group((18.18± 11.82) m) decreased significantly (P＜ 0.05).Compared with the model group,such distances of sham-operation group ((107.33±20.35)m) and 7-NI groups(50 nmol/0.5 μl:(138.40±56.85)m,(86.97±36.20)m);100 nmol/0.5 μl:(86.97±36.20)m) increased significantly (P＜ 0.05).The normal group entered the central area significantly more times(2.25±2.05) than model group (0.25±0.46)and 200nmol/0.5μl 7-NI group (0.25± 0.46) did (P＜0.05),and the number of times entering the central area of the model group (0.25±0.46)was significantly lower than that of the sham-operation group (1.00 ± 1.07,P＜ 0.05) and 50 nmol/0.5 μl group (0.75 ± 1.16).Compared with the normal group ((46.53 ±41.16) s),the durations of stay in the central area of model group ((1.27 ± 1.92) s) and 200 nmol/0.5 μl 7-NI group ((1.53 ± 2.90) s) were shortened significantly (P＜0.05).Compared with the model group,the durations of stay in the central area of 100 nmol/0.5μl group ((36.54±67.80) s) was lengthened significantly (P＜ 0.05).Western blotting showed that the hippocampal nNOS protein levels of model group (0.43±0.11) and 200 nmol/0.5μl 7-NI group(0.56±0.08) significantly exceeded that of the normal group (0.04±0.02,P＜0.05).The levels of nNOS in sham-operation group (0.04 ±0.02) and 50 nmol/0.5 μl 7-NI group (0.22± 0.08),which were significantly lower than that of the model group (0.43 ± 0.11,P＜ 0.05),were similar to that of the normal group (0.04 ± 0.02,P＞ 0.05).Conclusion Intracerebroventricular injection 200 nmol/0.5 μl 7-NI solution results in depression-like behaviors and increased the expression of nNOS protein reflexively in rats.
RESUMEN
OBJECTIVE: To investigate the effect of NG-nitro-l-arginine methyl ester (l-NAME), a non-selective nitric oxide synthase (NOS) inhibitor, and 7-nitroindazole (7-NI), a selective neuronal NOS inhibitor, on oxidative stress and tissue damage in brain and liver and on DNA damage of peripheral blood lymphocytes in malathion intoxicated rats. METHODS: Malathion (150 mg/kg) was given intraperitoneally (i.p.) along with l-NAME or 7-NI (10 or 20 mg/kg, i.p.) and rats were euthanized 4 h later. The lipid peroxidation product malondialdehyde (MDA), nitric oxide (nitrite), reduced glutathione (GSH) concentrations and paraoxonase-1 (PON-1) activity were measured in both brain and liver. Moreover, the activities of glutathione peroxidase (GPx) acetylcholinesterase (AChE), and butyrylcholinesterase (BChE), total antioxidant capacity (TAC), glucose concentrations were determined in brain. Liver enzyme determination, Comet assay, histopathological examination of brain and liver sections and inducible nitric oxide synthase (iNOS) immunohistochemistry were also performed. RESULTS: (i) Rats treated with only malathion exhibited increased nitric oxide and lipid peroxidation (malondialdehyde) accompanied with a decrease in GSH content, and PON-1 activity in brain and liver. Glutathione peroxidase activity, TAC, glucose concentrations, AChE and BChE activities were decreased in brain. There were also raised liver aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities and increased DNA damage of peripheral blood lymphocytes (Comet assay). Malathion caused marked histopathological changes and increased the expression of iNOS in brain and liver tissues. (ii) In brain of malathion-intoxicated rats, l-NAME or 7-NI resulted in decreased nitrite and MDA contents while increasing TAC and PON1 activity. Reduced GSH and GPx activity showed an increase by l-NAME. AChE activity increased by 20 mg/kg l-NAME and 10 mg/kg 7-NI. AChE activity decreased by the higher dose of 7-NI while either dose of 7-NI resulted in decreased BChE activity. (iii) In liver of malathion-intoxicated rats, decreased MDA content was observed after l-NAME or 7-NI. Nitrite level was unchanged by l-NAME but increased after 7-NI which also resulted in decreased GSH concentration and PON1 activity. Either inhibitor resulted in decreased liver ALT activity. (iv) DNA damage of peripheral blood lymphocytes was markedly inhibited by l-NAME or 7-NI treatment. (v) iNOS expression in brain and liver decreased by l-NAME or 7-NI. (vi) More marked improvement of the histopathological alterations induced by malathion in brain and liver was observed after 7-NI compared with l-NAME. CONCLUSIONS: In malathion intoxicated rats, the neuronal NOS inhibitor 7-NI and to much less extent l-NAME were able to protect the brain and liver tissue integrity along with improvement in oxidative stress parameters. The decrease in DNA damage of peripheral blood lymphocytes by NOS inhibitors also suggests the involvement of nitric oxide in this process.
RESUMEN
The present study was designed to investigate the effects of chronic predictable stress (CPS) and chronic unpredictable stress (CUS) on immunological responses in KLH-sensitized rats and involvement of NOergic signaling pathways mediating such responses. Male Wistar rats (200-250g) were exposed to either CPS or CUS for 14days and IgG antibody levels and delayed type hypersensitivity (DTH) response was determined to assess changes in adaptive immunity. To evaluate the role of nitric oxide during such immunomodulation, biochemical estimation of stable metabolite of nitric oxide (NOx) and 3-nitrotyrosine (3-NT, a marker of peroxynitrite formation) were done in both blood and brain. Chronic stress exposure resulted in suppression of IgG and DTH response and elevated NOx and 3-NT levels, with a difference in magnitude of response in CPS vs CUS. Pretreatment with aminoguanidine (iNOS inhibitor) caused further reduction of adaptive immune responses and attenuated the increased NOx and 3-NT levels in CPS or CUS exposed rats. On the other hand 7-NI (nNOS inhibitor) did not significantly affect these estimated parameters. The results suggest involvement of iNOS and lesser/no role of nNOS during modulation of adaptive immunity to stress. Thus, the result showed that predictability of stressors results in differential degree of modulation of immune responses and complex NO-mediated signaling mechanisms may be involved during responses.
Asunto(s)
Encéfalo/metabolismo , Hipersensibilidad Tardía/inmunología , Óxido Nítrico/metabolismo , Estrés Psicológico/inmunología , Tirosina/análogos & derivados , Inmunidad Adaptativa , Animales , Enfermedad Crónica , Modelos Animales de Enfermedad , Hipersensibilidad Tardía/psicología , Inmunidad Humoral , Inmunoglobulina G/sangre , Terapia de Inmunosupresión , Masculino , Ratas , Restricción Física/psicología , Tirosina/metabolismoRESUMEN
We investigated the possible role of 7-nitroindazole (7-NI) in regulating serum neuron-specific enolase (NSE) and S100ß levels in a rat model of traumatic brain injury (TBI). We also explored the possible mechanism by which 7-NI may affect the level of NSE and S100ß. A total of 160 healthy adult male Sprague-Dawley rats were randomly divided into 2 groups: i) The saline-treated group and ii) the 7-NI-treated group. Using the random number table, the groups were further divided into four subgroups: i) The sham-injured group; ii) the TBI 6 h group; iii) the TBI 12 h group; and iv) the TBI 24 h group (n=20). Controlled cortical impact in rats was established. Serum NSE and S100ß levels, nitric oxide (NO) level, water content, Evans blue (EB) content, malondialdehyde (MDA) level and total superoxide dismutase (T-SOD) level in the brain tissue were measured. NO synthase (NOS) activity was measured at 6, 12 and 24 h after TBI. Pathological changes in brain tissue were studied by hematoxylin and eosin (H&E) staining at each time-point. NSE and S100ß levels, NO content, water content, EB content and MDA level in the brain tissue increased significantly after TBI. NOS activity was also increased significantly after TBI while T-SOD content in brain tissue was significantly reduced after TBI. H&E staining showed that brain damage was aggravated gradually after TBI. We concluded that the early application of 7-NI significantly reduced serum NSE and S100ß levels after TBI. The neuroprotective effects of 7-NI may be associated with reduced NOS activity, reduced NO content, alleviated brain edema, lower blood-brain barrier permeability and oxidative stress. Serum NSE and S100ß levels can reflect the therapeutic effect of 7-NI, which suggest a good diagnostic value.
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It is estimated that 2.1 million young adults used MDMA/Ecstasy in the last year in Europe. Vulnerable subjects can develop dependence after MDMA abuse but currently there does not exist an effective treatment for this disorder. The nitric oxide (NO) pathway seems to have an important role on the rewarding effects of different drugs and has been proposed as a new pharmacological treatment for psychostimulant addiction. In the present study, we intend to evaluate whether the blockade of the NO synthesis (NOS) interferes with the rewarding effects of MDMA in the conditioned preference place (CPP) paradigm in young adult male mice. Our results indicated that mice treated with 7-nitroindazole (a NOS inhibitor) did not show CPP after conditioning with MDMA (1.25mg/kg). These results demonstrated the role of the NO pathway in the rewarding effects of MDMA and suggested that the manipulation of this pathway could be a new therapeutic option for MDMA abuse.