Self-reported neurostimulant use among university students in Santa Maria, Rio Grande do Sul, Brazil.

University students frequently resort to psychostimulants to enhance their physical and mental performance and manage academic pressures. However, these substances can lead to dependence and other undesired symptoms, and little empirical data are available for relevant stakeholders, raising significant concerns in health care. Therefore, this study aims to characterize neurostimulant use among university students in Rio Grande do Sul, Brazil. We collected from 880 students' data using anonymous self-administration. The questionnaire included consumption patterns of caffeine, nicotine, ecstasy, methamphetamine, "merla" (coca base), methylphenidate, cocaine, crack, and ketamine. Additionally, participants shared information on demographic and socioeconomic factors. Use of at least one neurostimulant was reported by89.2% of the participants. Among nonusers, the most frequently cited reason was "previous information about harmful effects of these drugs." Caffeine, followed by nicotine, ecstasy, and methylphenidate were the most consumed substances, with main reasons being "improving academic performance" and "recreation." Women more often consumed caffeine (72.7%), while other psychostimulants were more consumed by men (42.2%) and individuals of other genders (0.5%). Students who consumed other substances had higher family incomes than that of families of caffeine users. In addition, 60.4% of caffeine users resided with family members, whereas 63.3% of users of other substances did not. Our findings can offer essential data on the reasons and symptoms associated with the use of neurostimulants among university students. This information could aid in raising awareness among students, universities, and health-care agencies about this often-neglected subject.

What do we know about the sleep effects of caffeine used to treat apnoea of prematurity? A systematic review of the literature.

OBJECTIVE: Scientific scrutiny has proved the safety and benefits of caffeine to treat apnoea of prematurity (AOP). However, there is no consensus on the effects of this treatment on sleep, especially considering the key role of adenosine and early brain development for sleep maturation. We systematically reviewed studies with sleep as a primary and/or secondary outcome or any mention of sleep parameters in the context of caffeine treatment for AOP. METHODS: We performed a systematic search of PubMed, Web of Science and the Virtual Health Library from inception to 7 September 2022 to identify studies investigating the short- and long-term effects of caffeine to treat AOP on sleep parameters. We used the PIC strategy considering preterm infants as the Population, caffeine for apnoea as the Intervention and no or other intervention other than caffeine as the Comparison. We registered the protocol on PROSPERO (CRD42021282536). RESULTS: Of 4019 studies, we deemed 20, including randomised controlled trials and follow-up and observational studies, to be eligible for our systematic review. The analysed sleep parameters, the evaluation phase and the instruments for sleep assessment varied considerably among the studies. The main findings can be summarised as follows: (i) most of the eligible studies in this systematic review indicate that caffeine used to treat AOP seems to have no effect on key sleep parameters and (ii) the effects on sleep when caffeine is administered earlier, at higher doses or for longer periods than the most common protocol have not been investigated. There is a possible correlation between the caffeine concentration and period of exposure and negative sleep quality, but the sleep assessment protocols used in the included studies did not have high-quality standards and could not provide good evidence. CONCLUSIONS AND IMPLICATIONS: Sleep quality is an important determinant of health, and better investments in research with adequate sleep assessment tools are necessary to guarantee the ideal management of children who were born preterm.

Behavioral, genetic and biochemical changes in the brain of the offspring of female mice treated with caffeine during pregnancy and lactation.

The intrauterine environment is a critical location for exposure to exogenous and endogenous factors that trigger metabolic changes through fetal programming. Among the external factors, chemical compounds stand out, which include caffeine, since its consumption is common among women, including during pregnancy. Thereby, the aim of the present study was to evaluate the behavioral, genetic, and biochemical parameters in the offspring of female mice treated with caffeine during pregnancy and lactation. Swiss female mice (60 days old) received tap water or caffeine at 0.3 or 1.0 mg/mL during copulation (7 days), pregnancy (21 days) and lactation (21 days). After the end of the lactation period, the offspring were divided into groups (water, caffeine 0.3 or 1.0 mg/mL) with 20 animals (10 animals aged 30 days and 10 animals aged 60 days per group per sex). Initially, the offspring were submitted to behavioral tasks and then euthanized for genetic and biochemical analysis in the brain (cortex, striatum, and hippocampus). Behavioral changes in memory, depression, and anxiety were observed in the offspring: 30-day-old female offspring at 1.0 mg /mL dose presented anxiogenic behavior and male offspring the 0.3 mg/mL dose at 30 days of age did not alter long-term memory. Furthermore, an increase in DNA damage and oxidative stress in the brain were observed in the offspring of both sexes. Furthermore, there were changes in Ape-1, BAX, and Bcl-2 in the female offspring hippocampus at 30 days of life. Thus, with this study, we can suggest genotoxicity, oxidative stress, and behavioral changes caused by caffeine during pregnancy and lactation in the offspring that were not treated directly, but received through their mothers; thus, it is important to raise awareness regarding caffeine consumption among pregnant and lactating females.

Nanoencapsulation of unsaturated omega-3 fatty acids as protection against oxidation: A systematic review and data-mining.

The chemical structure of unsaturated fatty acids makes them highly prone to oxidation, which decreases their nutritional properties. Nanocarriers have the ability to protect unstable nutraceuticals and take them to their specific targets. Thus, the aim is to determine the effectiveness of nanoencapsulation of omega-3 unsaturated fatty acids as protection against oxidation, as well as to apply data-mining approach to identify nanoencapsulation profiles. Three databases were used to search for studies focused on comparing omega-3 encapsulation to the active compound in its raw form. Studies without oxidation test or no use omega 3-rich oil as active ingredient in nanoformulations were excluded. Twenty-three studies were included in the systematic review. The qualitative analysis indicated that the main evaluated parameters were encapsulation efficiency (%), physical-chemical parameters and oxidation (analyzed at different storage temperatures), oil type, and whether the formulation was added to food. With regard to quantitative analysis, studies that did not perform oxidation tests focused on comparing free oil to the encapsulated one were excluded. Data-mining indicated that encapsulation efficiency and particle size were the main characteristic defining nanocarrier's effectiveness in protecting the oil against oxidation. Nevertheless, it is important to note the main characteristics associated with oil protection in nanocarriers.

Reversal of haloperidol-induced orofacial dyskinesia and neuroinflammation by isoflavones.

BACKGROUND: Schizophrenia is a mental illness and its pharmacological treatment consists in the administration of antipsychotics like haloperidol. However, haloperidol often causes extrapyramidal motor disorders such as tardive dyskinesia (TD). So far, there is no effective treatment against TD and alternatives for it have been sought. Isoflafones have been studied as neuroprotector and inhibitor of monoamine oxidase enzyme. Thus, the objective is to evaluate the possible protective effect of isoflavones against the induction of involuntary movements induced by haloperidol in an animal model. METHODS AND RESULTS: Male Wistar rats were treated with haloperidol (1 mg/kg/day) and/or isoflavones (80 mg/kg) for 28 days. Rats were submitted to behavioral evaluation to quantify vacuous chewing movements (VCM) and locomotor activity. In addition, the levels of pro-inflammatory cytokines were measured in the striatum. Haloperidol treatment reduced the locomotor activity and increased the number of VCM in rats. Co-treatment with isoflavones was able to reverse hypolocomotion and reduce the number of VCM. Besides, haloperidol caused significant increase in the proinflammatory cytokines (interleukin-1ß:IL-1ß, tumor necrosis factor-α: TNF-α and IL-6 and the co-treatment with isoflavones was able to reduce the levels of IL-1ß and TNF-α, but not IL-6. CONCLUSIONS: It is believed that the beneficial effect found with this alternative treatment is related to its anti-inflammatory potential and to the action on estrogen receptors (based on scientific literature findings). Finally, further studies are needed to elucidate the mechanisms of isoflavones in reducing motor disorders induced by antipsychotics.

Stress and its contribution to the development of depression symptoms are reduced in caregivers of elderly with higher educational level.

Caregivers of elderly people with neurodegenerative diseases are highly vulnerable to stressful situations and mood disorders due to their work conditions. Stress has been associated with an increased risk of developing depression, and studies have supported that caffeine consumption can act as an independent protective factor for disorder. This study investigated indexes of stress and depression symptoms in caregivers of the elderly with neurodegenerative diseases, their caffeine intake and the association between stress and depressive symptoms with the salivary biomarkers cortisol, nitric oxide and DNA damage. Participants (n = 81) were recruited from the community between July 2018 and April 2019. Stress was assessed using Lipp's Inventory of Stress Symptoms, and depressive symptoms were measured using the Hamilton Depressive Rating Scale. Participants provided a 72-hour recall of their diet to measure caffeine intake. Saliva samples were used to measure cortisol and nitric oxide. DNA damage was measured through micronuclei frequency after swabbing on the buccal mucosa. The majority of caregivers displayed stress and depressive symptoms. Stress was associated with educational level, tobacco use and total DNA damage. The indexes found in this population were not associated with caffeine intake or other salivary biomarkers, indicating that only some salivary molecules could be used as biomarkers for stress-related disorders. Caregivers of the elderly are exposed to stressful situations daily, however, we observed that educational level can reduce the psychological symptoms of stress and thus reduce the negative impact on quality of life.

Simvastatin-loaded nanoemulsions: development, characterization, stability study and toxicity assays.

Aim: The aim of this study is to prepare and characterize simvastatin-loaded nanoemulsions (SIM-LN) as well as evaluate their physicochemical properties and toxicity. Methodology & results: The SIM-LN were prepared, their characteristics evaluated for 30 days, and after that, the SIM-LN toxicity was evaluated using Vero cell culture and the in vivo model of Caenorhabditis elegans. The prepared SIM-LN had an average droplet size of 139 ± 22 nm, with high encapsulation rate (>98.4%). The storage at room temperature proved to be the most optimal condition. Toxicity assays demonstrated no toxicity. Conclusion: It was demonstrated that the surfactants used as emulsifiers optimized the properties without side effects, because no toxicity was measured in preliminary tests.

Toxicological evaluation of naringin-loaded nanocapsules in vitro and in vivo.

Naringin is a flavonoid widely known for its pharmacological properties, such as: anti-inflammatory and antioxidant ones, being an ally to avoid oxidative damage. Although naringin is an active easily found in citrus fruits, it has low bioavailability, biodistribution and also undergoes biotransformation in naringenin, limiting the described effects. The use of nanocapsules as drug carriers may increase solubility, improve biodistribution, impede the biotransformation thereof, and thus could improve the performance of naringin for use in treating neurological diseases. Therefore, the objective of this work is to produce a nanocapsule containing naringin, validate an analytical method by RP-HPLC to determination of the drug in nanoparticle and evaluate the toxicity. To that end, the blank nanocapsules (NB, without the drug) or naringin-loaded nanocapsules (NN) at the concentration of 2 mg/mL were prepared by interfacial deposition of the preformed polymer and the quantification of naringin by HPLC. Toxicity of the formulations was evaluated in vitro in rat hippocampal slices and in vivo models with C. elegans and Danio rerio (zebrafish). The analytical parameters evaluated (linearity, limit of detection and quantification, specificity, precision, accuracy and robustness) indicated adequate method to assay of naringin in nanocapsules by HPLC. There was no indication of toxicity by the nanocapsules in the evaluated biological assays.

The benefits of omega-3 fatty acid nanocapsulation for the enrichment of food products: a review / Os benefícios da nanoencapsulação de ácidos graxos da classe ômega-3 para o enriquecimento de produtos alimentícios: uma revisão

ABSTRACT Polyunsaturated fatty acids oxidize easily due to their chemical structure, causing a reduction of their nutritional properties. Nanostructured systems may be an alternative to protect fatty acids against oxidation, improving solubility and stability. Consequently, nutritional value of food is maintained as well as the sensory characteristics (color, flavor, texture, and aroma) when fatty acids are added to food products. The present study is a narrative review to introduce the potential benefits of omega-3 unsaturated fatty acids nanoparticles incorporated in food products. The literature review includes publications in English and Portuguese issued between March 1985 and March 2019, in PubMed, ScienceDirect and Web of Science databases. Manual searches were conducted in the articles references lists of the articles included to identify other relevant studies. There were studies that evaluated the stability of fatty acids in food products such as bread, fruit juice, milk, yogurt, and meat. In this study, the most used nanostructured systems for the incorporation of fatty acids were the nanocapsules and the nanoliposomes. Currently, the nanostructured system demonstrates a potential to improve protection of polyunsaturated fatty acids against oxidization and thermal degradation. In this way, they maintain their functional properties and their bioavailability increases and therapeutic efficacy and sensory properties are improved. There are several methodologies being tested, which makes it difficult to identify the most efficient formulation to protect fatty acids. Nanostructured systems seem to be the best alternative to protect polyunsatured fatty acids from oxidization. The encapsulation efficiency, particle's size and type are relevant factors to be considered to evaluate oxidization. In conclusion, the review showed that currently it is impossible to determine the most efficient methodology. Besides, nanoformulations should follow international guidelines to present more standardized and therefore more efficient particles.

RESUMO Os ácidos graxos poli-insaturados são facilmente oxidados devido à sua estrutura química, o que acarreta a diminuição de suas propriedades nutricionais. Nesse contexto, o sistema nanoestruturado pode ser uma alternativa para protegê-los contra a oxidação, melhorando a solubilidade e estabilidade. Consequentemente, quando são adicionados a produtos alimentares, o valor nutricional é mantido, bem como as características sensoriais (cor, sabor, textura e aroma). O presente estudo é uma revisão narrativa para apresentar os potenciais benefícios das nanopartículas com ácidos graxos insaturados da classe ômega-3 incorporados a produtos alimentícios. A literatura consultada incluiu publicações em inglês e em português, considerando o período entre março de 1985 e março de 2019, utilizando as bases de dados PubMed, ScienceDirect e Web of Science. Foram realizadas buscas manuais nas referências dos artigos incluídos, a fim de identificar outros estudos relevantes. Foram encontradas pesquisas que avaliaram a estabilidade dos ácidos graxos em produtos alimentícios, como pães, suco de fruta, leite, iogurte e carne. Neste estudo, as nanoestruturas mais utilizadas para a incorporação dos ácidos graxos foram as nanocápsulas e os nanolipossomas. Atualmente, o sistema nanoestruturado demonstra um potencial para melhorar a proteção desses ácidos poli-insaturados contra a oxidação e degradação térmica. Dessa forma, eles mantêm suas propriedades funcionais, aumenta-se sua biodisponibilidade e há melhora da eficácia terapêutica e das propriedades sensoriais. Existem diversas metodologias sendo testadas, o que dificulta a identificação de qual seria a formulação mais eficiente nessa proteção, mas os sistemas nanoestruturados parecem ser a melhor alternativa para proteger os ácidos graxos insaturados da oxidação. A eficiência de encapsulação bem como o tamanho e o tipo de partícula são fatores importantes a considerar na avaliação da oxidação. Em conclusão, a revisão demonstrou que atualmente a metodologia mais eficiente não é possível de ser identificada. Ademais, as nanoformulações devem seguir diretrizes do protocolo internacional para apresentar partículas mais padronizadas e, assim, eficientes.

Effects of lithium and valproate on ERK/JNK signaling pathway in an animal model of mania induced by amphetamine.

Bipolar disorder (BD) is a severe and chronic psychiatric disorder, characterized by recurrent mood episodes of depression and mania. Some studies have indicated that there are ERK and JNK pathways alterations in the brain from bipolar patients. The animal model of mania induced by dextroamphetamine (d-AMPH) has been considered an excellent model to study intracellular alterations related to BD. The present study aimed to evaluate the effects of lithium (Li) and valproate (VPA) on the behavioral and ERK1/2/JNK1/2 signaling pathway in an animal model of mania induced by d-AMPH. Wistar rats were first given d-AMPH or saline (Sal) for 14 days, and then, between the 8th and 14th days, the rats were treated with Li, VPA, or Sal. The open-field test was used to evaluate the locomotion and exploration behaviors of rats. The levels of phosphorylated ERK1/2 and JNK1/2 were assessed in the hippocampus and frontal cortex of the rats. Li and VPA reversed the increased of locomotion and exploration induced by d-AMPH. The treatment with VPA or AMPH per se decreased the levels of pERK1 in the hippocampus. The treatment with VPA in the animals submitted to the administration of d-AMPH decreased the levels of ERK1, JNK-1, and JNK-2 phosphorylated in the hippocampus of the animals. The treatment with Li decreased the JNK-1 phosphorylated in the hippocampus of the animals submitted to the animal model of mania induced by d-AMPH. Although the association of VPA plus amphetamine alters some proteins involved in the JNK pathway in the hippocampus, these alterations were very random and seemed that were not related to the d-AMPH-induced manic-like behavior. These results suggest that the manic-like effects induced by d-AMPH and the antimanic effects of mood stabilizers, Li and VPA, are not related to the alteration on ERK1/2 and JNK1/2 pathways.

Caffeine Neuroprotection Decreases A2A Adenosine Receptor Content in Aged Mice.

Caffeine is a bioactive compound worldwide consumed with effect into the brain. Part of its action in reducing incidence or delaying Alzheimer's and Parkinson's diseases symptoms in human is credited to the adenosine receptors properties. However, the impact of caffeine consumption during aging on survival of brain cells remains debatable. This work, we investigated the effect of low-dose of caffeine on the ectonucleotidase activities, adenosine receptors content, and paying particular attention to its pro-survival effect during aging. Male young adult and aged Swiss mice drank water or caffeine (0.3 g/L) ad libitum for 4 weeks. The results showed that long-term caffeine treatment did not unchanged ATP, ADP or AMP hydrolysis in hippocampus when compared to the mice drank water. Nevertheless, the ATP/ADP hydrolysis ratio was higher in young adult (3:1) compared to the aged (1:1) animals regardless of treatment. The content of A1 receptors did not change in any groups of mice, but the content of A2A receptors was reduced in hippocampus of mice that consumed caffeine. Moreover, the cell viability results indicated that aged mice not only had increased pyknotic neurons in the hippocampus but also had reduced damage after caffeine treatment. Overall, these findings indicate a potential neuroprotective effect of caffeine during aging through the adenosinergic system.

Efeitos da ação dos ácidos graxos na pele sadia por biometria cutânea / Action eff ects of fatty acids in healthy skin by skin biometry

Neste estudo objetivou-se investigar o efeito da aplicação tópica dos óleos de chia, girassol e canola, por meio de biometria cutânea, mensurando a hidratação, Perda Transepidérmica de Água (PTEA), oleosidade e eritema. Tratase de uma pesquisa experimental, com amostra de 44 voluntários, que utilizaram os respectivos óleos no cotovelo esquerdo por 28 dias e foram avaliados nos dias 0, 7, 14, 21 e 28. Observou-se que todos os óleos estudados aumentaram a hidratação do cotovelo, porém, o óleo de chia apresentou o melhor resultado. Na avaliação da PTEA o óleo de canola apresentou o menor índice, porém, todos os óleos testados aumentaram a oleosidade do cotovelo, em especial o óleo de girassol. O óleo que teve menor reação tecidual foi o óleo de chia, quando comparado aos outros óleos testados. Logo, conclui-se que este estudo comprova a efetividade do óleo de chia na hidratação e diminuição de eritema da pele, prevenindo dano tissular e proporcionando efeitos benéfi cos na pele

The present study aims to investigate the effects of the topical application of chia, sunfl ower and canola oils by cutaneous biometry, measuring hydration, Transepidermal Water Loss (TEWL), oiliness and erythema. This is an experimental study, with a sample of 44 volunteers, who used the respective oils in the left elbow for 28 days, and so on days 0, 7th, 14th, 21th and 28th. It was observed that all the oils studied increased hydration of the elbow, however, the chia oil showed the best result. In the evaluation of the PTEA, the canola oil had the lowest index, but all the oils tested increased the oiliness of the elbow, especially the sunfl ower oil. The oil that had the lowest tissue reaction was chia oil, when compared to the other oils tested. Therefore, it is concluded that this study proves the effectiveness of chia oil on the hydration and reduction of erythema of the skin, preventing tissue damage and providing benefi cial effects on the skin

The Role of NMDA Receptors in the Development of Brain Resistance through Pre- and Postconditioning.

Brain tolerance or resistance can be achieved by interventions before and after injury through potential toxic agents used in low stimulus or dose. For brain diseases, the neuroprotection paradigm desires an attenuation of the resulting motor, cognitive, emotional, or memory deficits following the insult. Preconditioning is a well-established experimental and clinical translational strategy with great beneficial effects, but limited applications. NMDA receptors have been reported as protagonists in the adjacent cellular mechanisms contributing to the development of brain tolerance. Postconditioning has recently emerged as a new neuroprotective strategy, which has shown interesting results when applied immediately, i.e. several hours to days, after a stroke event. Investigations using chemical postconditioning are still incipient, but nevertheless represent an interesting and promising clinical strategy. In the present review pre- and postconditioning are discussed as neuroprotective paradigms and the focus of our attention lies on the participation of NMDA receptors proteins in the processes related to neuroprotection.

Long-term effects of ageing and ovariectomy on aversive and recognition memory and DNA damage in the hippocampus of female rats.

OBJECTIVE: This study investigated the influence of ageing - in particular the decrease of gonadal hormone levels during the ageing process - on the memory and the levels of DNA damage in the hippocampus of female rats. METHODS: Three groups of female Wistar rats were investigated: Group I consisted of non-ovariectomised, adult animals (6 months old); Group II consisted of non-ovariectomised, aged animals (18 months old); and Group III consisted of ovariectomised, aged animals (18 months old). The memory of the animals in these groups was examined via novel object recognition and inhibitory avoidance tests. The hippocampus tissue samples of all animals were obtained via biopsy and used to quantify the DNA damage using a Comet Assay. RESULTS: According to our findings, the process of ageing results in a change during the behavioural tests. To prevent genotoxic damage to the hippocampus caused by the ageing process, lowered hormone levels seem to be part of a protective biochemical mechanism in the body of rats. Animals that were previously submitted to an ovariectomy adapted better to these lower levels of hormones. CONCLUSION: Our results indicate that ovariectomy can provide beneficial long-term effects on the memory. However, this could be specific to the kind of memory examined, as the aversive memory deficits caused by ageing were not affected by ovariectomy.

Effects of neuropeptide S on seizures and oxidative damage induced by pentylenetetrazole in mice.

Neuropeptide S (NPS) and its receptor were recently discovered in the central nervous system. In rodents, NPS promotes hyperlocomotion, wakefulness, anxiolysis, anorexia, and analgesia and enhances memory when injected intracerebroventricularly (i.c.v.). Herein, NPS at different doses (0.01, 0.1 and 1nmol) was i.c.v. administered in mice challenged with pentylenetetrazole (PTZ; 60mg/kg) repeatedly injected. Aiming to assess behavioral alterations and oxidative damage to macromolecules in the brain, NPS was injected 5min prior to the last dose of PTZ. The administration of NPS only at 1nmol increased the duration of seizures evoked by PTZ, without modifying frequency and latency of seizures. Biochemical analysis revealed that NPS attenuated PTZ-induced oxidative damage to proteins and lipids in the hippocampus and cerebral cortex. In contrast, the administration of NPS to PTZ-treated mice increased DNA damage in the hippocampus, but not cerebral cortex. In conclusion, this is the first evidence of the potential proconvulsive effects of NPS in mice. The protective effects of NPS against lipid and protein oxidative damage in the mouse hippocampus and cerebral cortex evoked by PTZ-induced seizures are quite unexpected. The present findings were discussed analyzing the paradoxical effects of NPS: facilitation of convulsive behavior and protection against oxidative damage to lipids and proteins.

Role of the ecto-nucleotidases in the cooperative effect of adenosine and neuropeptide-S on locomotor activity in mice.

Activation of adenosine receptors modifies the action of classic neurotransmitters (i.e. dopamine, glutamate and acetylcholine) and other neuromodulators, like vasoactive intestinal peptide (VIP), calcitonin gene-related peptide (CGRP) and neuropeptide S (NPS). Similarly to adenosine, NPS is involved in the regulation of stimulus and response to fear and arousal. Thus, the present study investigates the effects of NPS on locomotor activity in mice treated with or without α,ß-methylene adenosine 5'-diphosphate (AOPCP), the inhibitor of ecto-5'-nucleotidase. Additionally, we evaluate the activity of ecto-5'-nucleotidase in brain slices of mice treated with or without NPS. Male adult CF-1 mice received i.c.v. NPS as 0.1 nmol injection with or without pre-treatment with 1 nmol α,ß-methylene adenosine 5'-diphosphate (AOPCP), the selective inhibitor of ecto-5'-nucleotidase, to evaluate locomotor activity. In another set of experiments, mice received i.c.v. infusion of 0.1 nmol NPS to assay enzymatic activity in brain slices. The results demonstrated that the pre-treatment with AOPCP, which was inactive per se, prevented NPS-induced hyperlocomotion in mice. The dose of 0.1 nmol NPS was efficient to induce hyperlocomotion in animals during the observation period in the activity cage. Regarding enzymatic activity, i.c.v. NPS injection did not induce any significant alterations in ATP and AMP hydrolysis in striatum and hippocampus brain slices of mice. The present study shows that the hyperlocomotor effect of NPS depends on the ecto-5'-nucleotidase activity.

NMDA preconditioning protects against quinolinic acid-induced seizures via PKA, PI3K and MAPK/ERK signaling pathways.

Preconditioning by N-methyl-d-aspartate (NMDA) may be promoted in vivo by the administration of a sub-convulsing dose of NMDA, with a neuroprotective effect against seizures and neuronal death induced by the infusion of quinolinic acid (QA) in mice. This study aimed to evaluate the participation of protein kinase C (PKC), cyclic AMP-dependent protein kinase (PKA), mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) kinase (MEK), Ca(2+)/calmodulin dependent protein kinase II (CaMKII) and phosphatidilinositol-3 kinase (PI3K) signaling pathways in this neuroprotection model. Adult Swiss male mice were preconditioned with NMDA 24 h before the infusion of QA, and were treated with inhibitors of the aforementioned signaling pathways either 15 min before the preconditioning or infusion of QA. Inhibition of the PKA and PI3K pathways abolished the protection evoked by NMDA, and inhibition of the MEK pathway significantly diminished this protection. Treatment with PKC and CaMKII inhibitors did not alter the protection rate. Inhibition of the MEK and PKC pathways resulted in an increased mortality rate when followed by the infusion of QA, or NMDA preconditioning and QA infusion, respectively. These results suggest that the PKA, PI3K and MEK pathways have a crucial role in the achievement of a neuroprotective state following preconditioning.

N-methyl-D-aspartate glutamate receptor blockade attenuates lung injury associated with experimental sepsis.

BACKGROUND: The aim of this study was to examine the effects of the N-methyl-D-aspartate receptor (NMDAR) channel blocker dizocilpine (MK-801) on lung injury in rats submitted to experimental sepsis induced by cecal ligation and perforation (CLP). METHODS: Adult male Wistar rats submitted to CLP were given a single systemic injection of MK-801 (subcutaneously at 0.3 mg/kg) administered 4 or 7 h after CLP induction. Twelve hours after CLP BAL was performed to determine total cell count, protein content, and inflammatory parameters. In addition, lung was excised for histopathologic analyses and determination of NMDAR subunits content. In a separate cohort of animals mortality was recorded for 5 days. RESULTS: Animals submitted to sepsis induced by CLP showed an increase in the content of NMDAR subunits NR1 and NR2A in the lung. Administration of MK-801 4 h after CLP induction resulted in a decrease in BAL fluid cellular content and decreased levels of proinflammatory cytokines. In addition, MK-801 decreased lung oxidative stress markers and histopathologic alterations and improved survival. CONCLUSIONS: These findings indicate that NMDAR blockade might represent a promising novel therapeutic strategy for the treatment of sepsis and inflammatory disorders.

Evaluation of glutathione metabolism in NMDA preconditioning against quinolinic acid-induced seizures in mice cerebral cortex and hippocampus.

Brain preconditioning refers to a wide range of treatments that induce a neuronal tolerance state where neuronal tissue become more resistant to a subsequent lethal insult. The mechanisms underlying the preconditioning-induced brain tolerance are not fully understood, but up-regulation of antioxidant enzymes activity has been suggested to play an important role. In order to test this hypothesis, evaluation of glutathione (GSH) scavenger system was carried out in mice showing the neuroprotective effect of NMDA preconditioning against quinolinic acid (QA)-induced seizures. NMDA is known to prevent seizures in 53% of the animals and completely prevent neural damage against QA. Mice were preconditioned by a non-convulsant NMDA dose (75 mg/kg, 10 ml/kg i.p.) 24 h before QA infusion (4 microl, 9.2 mM i.c.v.). GSH content and enzymatic activities of glutathione peroxidase (GPx), glutathione reductase (GR), glutathione S-transferase (GST) and glucose-6-phosphate dehydrogenase (G6PDH) were evaluated in the cerebral cortex and hippocampus 24 h after QA infusion. NMDA preconditioning and QA infusion did not alter GSH content, GR and G6PDH activities, however, an increase in GST activity was observed in the cerebral cortex from mice. Moreover, NMDA pretreatment was able to prevent the QA-induced decrease in hippocampal GPx activity, but it was not effective against the decreased cortical GPx activity. These results indicate that, although NMDA preconditioning and QA toxicity modulate the activity of some GSH related enzymes, GSH metabolism is not directly linked to the neuroprotective effect induced by NMDA preconditioning.

Kinetic characterization and immunodetection of ecto-ATP diphosphohydrolase (EC 3.6.1.5) in cultured hippocampal neurons.

Extracellular ATP and adenosine modulate synaptic transmission in hippocampal neurons. ATP released from neural cells is hydrolyzed to adenosine by a chain of ecto-nucleotidases. ATP diphosphohydrolase hydrolyses ATP and ADP nucleotides to AMP and 5'-nucleotidase hydrolyses AMP to adenosine. In this work, we investigated the ATPase and ADPase activities of ATP diphosphohydrolase in cultured hippocampal neurons. The apparent Michaelis-Menten constant (K(m)) was 233.9 +/- 14.6 and 221.8 +/- 63.6 microM, with a calculated maximal velocity (V(max), approximately) of 49.2 +/- 10.7 and 10.9 +/- 5.2 nmol Pi/mg protein/min for ATP and ADP, respectively. The horizontal straight line obtained in the competition plot indicated that only one active site is able to hydrolyze both substrates. Furthermore, we detected the presence of this enzyme using anti-CD39 antibody, which strongly stained the soma of pyramidal and bipolar neurons, but the neurites connecting the cell clusters were also immunopositive. This antibody recognized three bands with a molecular mass close to 95, 80 and 60kDa in immunoblotting analysis. The present results show, for the first time, the kinetic and immunocytochemical characterization of an ATP diphosphohydrolase in cultured hippocampal neurons. Probably, the widespread distribution of this enzyme on the surface of neurons in culture could reflect its functional importance in studies of synaptic plasticity hippocampal.