RESUMO
Increasing evidence suggests that plant-derived extracts and their isolated components are useful for treatment of seizures and, hence, constitute a valuable source of new antiepileptic drugs with improved efficacy and better adverse effect profile. ß-Caryophyllene is a natural bicyclic sesquiterpene that occurs in a wide range of plant species and displays a number of biological actions, including neuroprotective activity. In the present study, we tested the hypothesis that ß-caryophyllene displays anticonvulsant effects. In addition, we investigated the effect of ß-caryophyllene on behavioral parameters and on seizure-induced oxidative stress. Adult C57BL/6 mice received increasing doses of ß-caryophyllene (0, 10, 30, or 100mg/kg). After 60 min, we measured the latencies to myoclonic and generalized seizures induced by pentylenetetrazole (PTZ, 60 mg/kg). We found that ß-caryophyllene increased the latency to myoclonic jerks induced by PTZ. This result was confirmed by electroencephalographic analysis. In a separate set of experiments, we found that mice treated with an anticonvulsant dose of ß-caryophyllene (100mg/kg) displayed an improved recognition index in the object recognition test. This effect was not accompanied by behavioral changes in the open-field, rotarod, or forced swim tests. Administration of an anticonvulsant dose of ß-caryophyllene (100mg/kg) did not prevent PTZ-induced oxidative stress (i.e., increase in the levels of thiobarbituric acid-reactive substances or the decrease in nonprotein thiols content). Altogether, the present data suggest that ß-caryophyllene displays anticonvulsant activity against seizures induced by PTZ in mice. Since no adverse effects were observed in the same dose range of the anticonvulsant effect, ß-caryophyllene should be further evaluated in future development of new anticonvulsant drugs.
Assuntos
Anticonvulsivantes/uso terapêutico , Convulsivantes , Pentilenotetrazol , Convulsões/induzido quimicamente , Convulsões/tratamento farmacológico , Sesquiterpenos/uso terapêutico , Animais , Relação Dose-Resposta a Droga , Eletroencefalografia/efeitos dos fármacos , Epilepsias Mioclônicas/induzido quimicamente , Epilepsias Mioclônicas/tratamento farmacológico , Epilepsias Mioclônicas/psicologia , Camundongos , Camundongos Endogâmicos C57BL , Atividade Motora/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Sesquiterpenos Policíclicos , Equilíbrio Postural/efeitos dos fármacos , Reconhecimento Psicológico , Convulsões/psicologia , Natação/psicologiaRESUMO
Statins are inhibitors of the enzyme 3-hydroxy-3-methylglutaryl coenzyme A reductase, the rate-limiting step in cholesterol biosynthesis. Statins effectively prevent and reduce the risk of coronary artery disease through lowering serum cholesterol, and also exert anti-thrombotic, anti-inflammatory and antioxidant effects independently of changes in cholesterol levels. On the other hand, clinical and experimental evidence suggests that abrupt cessation of statin treatment (i.e. statin withdrawal) is associated with a deleterious rebound phenomenon. In fact, statin withdrawal increases the risk of thrombotic vascular events, causes impairment of endothelium-dependent relaxation and facilitates experimental seizures. However, evidence for statin withdrawal-induced detrimental effects to the brain parenchyma is still lacking. In the present study adult male Wistar rats were treated with atorvastatin for seven days (10mg/kg/day) and neurochemical assays were performed in the cerebral cortex 30 min (atorvastatin treatment) or 24h (atorvastatin withdrawal) after the last atorvastatin administration. We found that atorvastatin withdrawal decreased levels of nitric oxide and mitochondrial superoxide dismutase activity, whereas increased NADPH oxidase activity and immunoreactivity for the protein nitration marker 3-nitrotyrosine in the cerebral cortex. Catalase, glutathione-S-transferase and xanthine oxidase activities were not altered by atorvastatin treatment or withdrawal, as well as protein carbonyl and 4-hydroxy-2-nonenal immunoreactivity. Immunoprecipitation of mitochondrial SOD followed by analysis of 3-nitrotyrosine revealed increased levels of nitrated mitochondrial SOD, suggesting the mechanism underlying the atorvastatin withdrawal-induced decrease in enzyme activity. Altogether, our results indicate the atorvastatin withdrawal elicits oxidative/nitrosative damage in the rat cerebral cortex, and that changes in NADPH oxidase activity and mitochondrial superoxide dismutase activities may underlie such harmful effects.
Assuntos
Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/metabolismo , Ácidos Heptanoicos/efeitos adversos , Inibidores de Hidroximetilglutaril-CoA Redutases/efeitos adversos , Pirróis/efeitos adversos , Síndrome de Abstinência a Substâncias/etiologia , Síndrome de Abstinência a Substâncias/metabolismo , Animais , Atorvastatina , Córtex Cerebral/enzimologia , Ácidos Heptanoicos/administração & dosagem , Inibidores de Hidroximetilglutaril-CoA Redutases/administração & dosagem , Masculino , Óxido Nítrico/metabolismo , Oxirredução , Pirróis/administração & dosagem , Ratos , Ratos Wistar , Síndrome de Abstinência a Substâncias/enzimologia , Superóxido Dismutase/metabolismo , Tirosina/análogos & derivados , Tirosina/metabolismoRESUMO
Recently, research for alternative methods to combat gastrointestinal parasites has increased, and the biological control activity of the fungus Duddingtonia flagrans stands out. In this study, the possible influence of temperature on the nematophagous activity of D. flagrans, after gastrointestinal passage, against Haemonchus contortus in sheep was analysed. Four female sheep, between 2 and 3 years of age and weighing between 40 and 50 kg, were used. Two sheep were parasitised with H. contortus, while two other sheep were dewormed. Before the collection of faeces, one of the dewormed animals received a dosage of 1 × 10(6) chlamydospores of D. flagrans, lyophilised in gelatin capsules, for three consecutive days. The faeces were collected with collector bags, mixed, and then separated as samples with (fungus; 800 eggs per gram (EPG) of faeces) or without fungus (control; 900 EPG). Each sample (five replicates) was maintained in a biochemical oxygen demand incubator under different temperatures (5, 10, 15, 20, 25, 30, or 35 °C) for 21 days, followed by determination of the larval recovery. Compared to the control group, the best temperature for fungal action was 30 °C, while no larvae were recovered at 5 °C. At 10 °C, fungal action was detected, yet there was no significant difference in the percent larval reduction between all temperatures, demonstrating that larval presence seems to be the main factor affecting the nematophagous action of D. flagrans. Temperature does not appear to be a limiting factor in the biological control activity of D. flagrans against H. contortus, but larval presence, which was not observed at 5 °C, is mandatory. At low temperatures, which are typically suboptimal conditions for fungal and larval development, the lyophilised D. flagrans reduced the number of H. contortus larvae, which demonstrates the biological control potential and the potential use of D. flagrans in the subtropics.
Assuntos
Duddingtonia/crescimento & desenvolvimento , Hemoncose/veterinária , Haemonchus/crescimento & desenvolvimento , Helmintíase Animal/parasitologia , Enteropatias/veterinária , Controle Biológico de Vetores/métodos , Doenças dos Ovinos/parasitologia , Animais , Fezes/parasitologia , Feminino , Hemoncose/terapia , Helmintíase/terapia , Enteropatias/terapia , Enteropatias Parasitárias , Ovinos , TemperaturaRESUMO
Exercise induces brain function adaptations and improves learning and memory; however the time window of exercise effects has been poorly investigated. Studies demonstrate an important role for cyclooxygenase-2 (COX-2) pathway function in the mechanisms underlying memory formation. The aim of present work was to investigate the effects of treadmill exercise on aversive memory and COX-2, PGE(2) and E-prostanoid receptors contents in the rat hippocampus at different time points after exercise has ended. Adult male Wistar rats were assigned to non-exercised (sedentary) and exercised (running daily for 20min, for 2weeks) groups. The inhibitory avoidance task was used to assess aversive memory and the COX-2, PGE(2) and E-prostanoid receptors (EP1, EP2, EP3 and EP4) levels were determined 1h, 18h, 3days or 7days after the last training session of treadmill exercise. The step down latency in the inhibitory avoidance, COX-2 and EP4 receptors levels were acutely increased by exercise, with a significant positive correlation between aversive memory performance and COX-2 levels. Increased EP2 content decreased PGE(2) levels were observed 7days after the last running session. The treadmill exercise protocol facilitates inhibitory avoidance memory and induces time-dependent changes on COX-2 pathways function (COX-2, PGE(2) and EP receptors).
Assuntos
Aprendizagem da Esquiva/fisiologia , Ciclo-Oxigenase 2/metabolismo , Dinoprostona/metabolismo , Hipocampo/metabolismo , Memória/fisiologia , Condicionamento Físico Animal/fisiologia , Receptores de Prostaglandina E/metabolismo , Animais , Masculino , Ratos , Ratos Wistar , Fatores de TempoRESUMO
PURPOSE: Statins are selective inhibitors of 3-hydroxyl-3-methyl-glutaryl coenzyme A (HMG-CoA) reductase, the rate-limiting enzyme of the mevalonate pathway for cholesterol biosynthesis. Increasing evidence indicates that statins, particularly atorvastatin, are neuroprotective in several conditions, including stroke, cerebral ischemia, traumatic brain injury, and excitotoxic amino acid exposure. However, only a few studies have investigated whether statins modulate seizure activity. In the current study we investigated whether atorvastatin or simvastatin alters the seizures induced by pentylenetetrazol (PTZ), a classical convulsant. METHODS: Adult male Wistar rats were treated with atorvastatin or simvastatin for 7 days (10 mg/kg/day). Seizure activity was induced by PTZ (60 mg/kg, i.p.), and evaluated by behavioral and electrographic methods. Cholesterol levels were determined by a standard spectrophotometric method. Blood-brain barrier (BBB) permeability was assessed by the fluorescein method. Atorvastatin levels in the plasma and cerebral cortex were determined by high-performance liquid chromatography tandem mass spectrometry. KEY FINDINGS: We found that oral atorvastatin treatment increased the latency to PTZ-induced generalized seizures. In contrast, when the 7-day atorvastatin treatment was withheld for 1 day (i.e., atorvastatin withdrawal), PTZ-induced seizures were facilitated, as evidenced by a decrease in the latency to clonic and generalized tonic-clonic seizures induced by PTZ. In contrast, simvastatin treatment for 7 days (10 mg/kg/day, p.o.), with or without withdrawal, did not alter PTZ-induced seizures. Interestingly, the effects of atorvastatin treatment and withdrawal were not accompanied by changes in plasma or cerebral cortex cholesterol levels or in the BBB permeability. Atorvastatin levels in the plasma and cerebral cortex after 7 days of treatment were above the half maximal inhibitory concentration for inhibition of HMG-CoA reductase, whereas atorvastatin was not detectable in the plasma or cerebral cortex following a 24 h washout period (atorvastatin withdrawal). SIGNIFICANCE: We conclude that atorvastatin treatment and withdrawal have differential effects on pentylenetetrazol-induced seizures, which are not related to changes in plasma or cerebral cortex cholesterol levels or in BBB permeability. Additional studies are necessary to evaluate the molecular mechanisms underlying our findings as well as its clinical implications.
Assuntos
Anticonvulsivantes/farmacologia , Convulsivantes/farmacologia , Ácidos Heptanoicos/farmacologia , Pentilenotetrazol/farmacologia , Pirróis/farmacologia , Convulsões/tratamento farmacológico , Animais , Anticonvulsivantes/administração & dosagem , Anticonvulsivantes/análise , Anticonvulsivantes/sangue , Atorvastatina , Barreira Hematoencefálica/metabolismo , Córtex Cerebral/química , Colesterol/sangue , Eletroencefalografia , Ácidos Heptanoicos/administração & dosagem , Ácidos Heptanoicos/análise , Ácidos Heptanoicos/sangue , Masculino , Pirróis/administração & dosagem , Pirróis/análise , Pirróis/sangue , Ratos , Ratos Wistar , Convulsões/induzido quimicamente , Sinvastatina/administração & dosagem , Sinvastatina/farmacologiaRESUMO
This study evaluated the in vivo anticonvulsant effect of a spray-dried powder for reconstitution containing phenytoin-loaded lipid-core nanocapsules. The effect of chitosan coating on redispersibility, gastrointestinal stability, and drug release from nanoparticles was evaluated during the development of the powders. Maltodextrin was used as adjuvant in the spray-drying process. Chitosan coating played an important role in redispersibility, and large particles (>100⯵m) were obtained using the highest concentration of solids in the feed. However, after aqueous redispersion, volume-based particle size was reduced to about 1⯵m. The release of nanoparticles from the surface of the spherical microagglomerates (roundness indexâ¯=â¯0.75) was confirmed by SEM analysis. Powders reconstituted in water recovered partially the nanometric properties of the original suspensions and were stable for 24â¯h. Phenytoin-loaded chitosan-coated nanocapsules and their redispersed powders have good gastrointestinal stability, and are able to control drug release in simulated gastric and intestinal fluids. Besides that, the reconstituted powder containing chitosan-coated nanocapsules exhibited improved anticonvulsant activity against seizures induced by pilocarpine in mice, compared to the non-encapsulated drug, representing an important approach in anticonvulsant treatments for children and adults.
Assuntos
Anticonvulsivantes/administração & dosagem , Nanocápsulas/administração & dosagem , Fenitoína/administração & dosagem , Animais , Anticonvulsivantes/química , Quitosana/administração & dosagem , Quitosana/química , Dessecação , Composição de Medicamentos , Liberação Controlada de Fármacos , Feminino , Masculino , Camundongos Endogâmicos C57BL , Nanocápsulas/química , Fenitoína/química , Pilocarpina , Polissacarídeos/administração & dosagem , Polissacarídeos/química , Pós , Convulsões/induzido quimicamente , Convulsões/tratamento farmacológicoRESUMO
This article has been withdrawn at the request of the author(s) and/or editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy.
RESUMO
Temporal lobe epilepsy (TLE) is the most common type of epilepsy with about one third of TLE patients being refractory to antiepileptic drugs. Knowledge about the mechanisms underlying seizure activity is fundamental to the discovery of new drug targets. Brain Na(+),K(+)-ATPase activity contributes to the maintenance of the electrochemical gradients underlying neuronal resting and action potentials as well as the uptake and release of neurotransmitters. In the present study we tested the hypothesis that decreased Na(+),K(+)-ATPase activity is associated with changes in the alpha subunit phosphorylation and/or redox state. Activity of Na(+),K(+)-ATPase decreased in the hippocampus of C57BL/6 mice 60 days after pilocarpine-induced status epilepticus (SE). In addition, the Michaelis-Menten constant for ATP of α2/3 isoforms increased at the same time point. Nitration of the α subunit may underlie decreased Na(+),K(+)-ATPase activity, however no changes in expression or phosphorylation state at Ser(943) were found. Further studies are necessary define the potential of nitrated Na(+),K(+)-ATPase as a new therapeutic target for seizure disorders.
Assuntos
Hipocampo/enzimologia , ATPase Trocadora de Sódio-Potássio/metabolismo , Estado Epiléptico/enzimologia , Trifosfato de Adenosina/metabolismo , Animais , Modelos Animais de Doenças , Isoenzimas , Masculino , Camundongos Endogâmicos C57BL , Oxirredução , Fosforilação , Pilocarpina , ATPase Trocadora de Sódio-Potássio/genéticaRESUMO
RATIONALE: There are evidences indicating the role of kinins in pathophysiology of traumatic brain injury, but little is known about their action on memory deficits. OBJECTIVES: Our aim was to establish the role of bradykinin receptors B1 (B1R) and B2 (B2R) on the behavioral, biochemical, and histologic features elicited by moderate lateral fluid percussion injury (mLFPI) in mice. METHODS: The role of kinin B1 and B2 receptors in brain damage, neuromotor, and cognitive deficits induced by mLFPI, was evaluated by means of subcutaneous injection of B2R antagonist (HOE-140; 1 or 10 nmol/kg) or B1R antagonist (des-Arg9-[Leu8]-bradykinin (DAL-Bk; 1 or 10 nmol/kg) 30 min and 24 h after brain injury. Brain damage was evaluated in the cortex, being considered as lesion volume, inflammatory, and oxidative damage. The open field and elevated plus maze tests were performed to exclude the nonspecific effects on object recognition memory test. RESULTS: Our data revealed that HOE-140 (10 nmol/kg) protected against memory impairment. This treatment attenuated the brain edema, interleukin-1ß, tumor necrosis factor-α, and nitric oxide metabolites content elicited by mLFPI. Accordingly, HOE-140 administration protected against the increase of nicotinamide adenine dinucleotide phosphate oxidase activity, thiobarbituric-acid-reactive species, protein carbonylation generation, and Na⺠K⺠ATPase inhibition induced by trauma. Histologic analysis showed that HOE-140 reduced lesion volume when analyzed 7 days after brain injury. CONCLUSIONS: This study suggests the involvement of the B2 receptor in memory deficits and brain damage caused by mLFPI in mice.
Assuntos
Bradicinina/análogos & derivados , Lesões Encefálicas/complicações , Lesões Encefálicas/tratamento farmacológico , Transtornos da Memória/etiologia , Transtornos da Memória/prevenção & controle , Fármacos Neuroprotetores/farmacologia , Animais , Bradicinina/metabolismo , Bradicinina/farmacologia , Antagonistas de Receptor B1 da Bradicinina/farmacologia , Antagonistas de Receptor B2 da Bradicinina/farmacologia , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Encéfalo/patologia , Edema Encefálico/etiologia , Edema Encefálico/metabolismo , Edema Encefálico/patologia , Edema Encefálico/prevenção & controle , Lesões Encefálicas/metabolismo , Lesões Encefálicas/patologia , Modelos Animais de Doenças , Masculino , Aprendizagem em Labirinto/efeitos dos fármacos , Aprendizagem em Labirinto/fisiologia , Transtornos da Memória/metabolismo , Transtornos da Memória/patologia , Camundongos , Atividade Motora/efeitos dos fármacos , Atividade Motora/fisiologia , NADPH Oxidases/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/fisiologia , Reconhecimento Psicológico/efeitos dos fármacos , Reconhecimento Psicológico/fisiologia , Fatores de TempoRESUMO
Traumatic brain injury (TBI) is a devastating disease that commonly causes persistent mental disturbances and cognitive deficits. Although studies have indicated that overproduction of free radicals, especially superoxide (O2(-)) derived from nicotinamide adenine dinucleotide phosphate (NADPH) oxidase is a common underlying mechanism of pathophysiology of TBI, little information is available regarding the role of apocynin, an NADPH oxidase inhibitor, in neurological consequences of TBI. Therefore, the present study evaluated the therapeutic potential of apocynin for treatment of inflammatory and oxidative damage, in addition to determining its action on neuromotor and memory impairments caused by moderate fluid percussion injury in mice (mLFPI). Statistical analysis revealed that apocynin (5mg/kg), when injected subcutaneously (s.c.) 30min and 24h after injury, had no effect on neuromotor deficit and brain edema, however it provided protection against mLFPI-induced object recognition memory impairment 7days after neuronal injury. The same treatment protected against mLFPI-induced IL-1ß, TNF-α, nitric oxide metabolite content (NOx) 3 and 24h after neuronal injury. Moreover, apocynin treatment reduced oxidative damage (protein carbonyl, lipoperoxidation) and was effective against mLFPI-induced Na(+), K(+)-ATPase activity inhibition. The present results were accompanied by effective reduction in lesion volume when analyzed 7days after neuronal injury. These data suggest that superoxide (O2(-)) derived from NADPH oxidase can contribute significantly to cognitive impairment, and that the post injury treatment with specific NADPH oxidase inhibitors, such as apocynin, may provide a new therapeutic approach to the control of neurological disabilities induced by TBI.
Assuntos
Acetofenonas/farmacologia , Lesões Encefálicas/complicações , Transtornos Cognitivos/tratamento farmacológico , Transtornos Cognitivos/etiologia , Inibidores Enzimáticos/farmacologia , Inflamação/patologia , NADPH Oxidases/antagonistas & inibidores , Nootrópicos/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Animais , Lesões Encefálicas/psicologia , Transtornos Cognitivos/psicologia , Citocinas/metabolismo , Discinesia Induzida por Medicamentos/prevenção & controle , Masculino , Memória/efeitos dos fármacos , Camundongos , Reconhecimento Psicológico/efeitos dos fármacosRESUMO
The methylmalonic acidemia is an inborn error of metabolism (IEM) characterized by methylmalonic acid (MMA) accumulation in body fluids and tissues, causing neurological dysfunction, mitochondrial failure and oxidative stress. Although neurological evidence demonstrate that infection and/or inflammation mediators facilitate metabolic crises in patients, the involvement of neuroinflammatory processes in the neuropathology of this organic acidemia is not yet established. In this experimental study, we used newborn Wistar rats to induce a model of chronic acidemia via subcutaneous injections of methylmalonate (MMA, from 5th to 28th day of life, twice a day, ranged from 0.72 to 1.67 µmol/g as a function of animal age). In the following days (29th-31st) animal behavior was assessed in the object exploration test and elevated plus maze. It was performed differential cell and the number of neutrophils counting and interleukin-1 beta (IL-1ß) and tumor necrosis factor-alpha (TNF-α) levels in the blood, as well as levels of IL-1ß, TNF-α, inducible nitric oxide synthase (iNOS) and 3-nitrotyrosine (3-NT) in the cerebral cortex were measured. Behavioral tests showed that animals injected chronically with MMA have a reduction in the recognition index (R.I.) when the objects were arranged in a new configuration space, but do not exhibit anxiety-like behaviors. The blood of MMA-treated animals showed a decrease in the number of polymorphonuclear and neutrophils, and an increase in mononuclear and other cell types, as well as an increase of IL-1ß and TNF-α levels. Concomitantly, MMA increased levels of IL-1ß, TNF-α, and expression of iNOS and 3-NT in the cerebral cortex of rats. The overall results indicate that chronic administration of MMA increased pro-inflammatory markers in the cerebral cortex, reduced immune system defenses in blood, and coincide with the behavioral changes found in young rats. This leads to speculate that, through mechanisms not yet elucidated, the neuroinflammatory processes during critical periods of development may contribute to the progression of cognitive impairment in patients with methylmalonic acidemia.