RESUMO
Obesity is characterized by chronic inflammation of low grade. The cholinergic anti-inflammatory pathway favors the reduction of the inflammatory response. In this work the effect of stimulation of the cholinergic anti-inflammatory pathway on SHIRPA behavioral test and mitochondrial respiratory chain activity in obese mice was evaluated. The animals were paired in four groups: saline + control diet; donepezil + control diet; saline + high-fat diet and donepezil + high-fat diet. 5 mg/kg/day orally of donepezil or saline were given 7 days before the beginning of the diet until completing 11 weeks of the experiment. Food intake and body weight were measured. At the end of the experiment the animals were submitted to the SHIRPA behavioral test, soon after they were killed by decapitation, the open abdominal cavity and the mesenteric fat were removed. The hypothalamus, hippocampus, prefrontal cortex, and striatum were removed for evaluation of the mitochondrial respiratory chain. It can be observed that donepezil prevented weight gain and food consumption, as well as a tendency to prevent the accumulation of mesenteric fat in obese animals. There was no behavioral change in obese animals, nor did the influence of donepezil on these parameters. On the other hand, donepezil did not prevent inhibition of complex I activity, prevented the inhibition of complex II, and showed a tendency to prevent IV complex activity inhibited in obesity. With these results it can be concluded that the activation of the cholinergic anti-inflammatory pathway is promising for the alterations found in obesity.
Assuntos
Fármacos Antiobesidade/uso terapêutico , Encéfalo/metabolismo , Donepezila/uso terapêutico , Metabolismo Energético/efeitos dos fármacos , Obesidade/prevenção & controle , Animais , Peso Corporal/efeitos dos fármacos , Dieta Hiperlipídica , Complexo I de Transporte de Elétrons/antagonistas & inibidores , Complexo I de Transporte de Elétrons/metabolismo , Complexo II de Transporte de Elétrons/antagonistas & inibidores , Complexo II de Transporte de Elétrons/metabolismo , Complexo IV da Cadeia de Transporte de Elétrons/antagonistas & inibidores , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Masculino , Camundongos , Obesidade/metabolismoRESUMO
This article reviews the interactions between nitric oxide (NO) and mitochondrial respiration. Mitochondrial ATP synthesis is responsible for virtually all energy production in mammals, and every other process in living organisms ultimately depends on that energy production. Furthermore, both necrosis and apoptosis, that summarize the main forms of cell death, are intimately linked to mitochondrial integrity. Endogenous and exogenous â¢NO inhibits mitochondrial respiration by different well-studied mechanisms and several nitrogen derivatives. Instantaneously, low concentrations of â¢NO, specifically and reversibly inhibit cytochrome c oxidase in competition with oxygen, in several tissues and cells in culture. Higher concentrations of â¢NO and its derivatives (peroxynitrite, nitrogen dioxide or nitrosothiols) can cause irreversible inhibition of the respiratory chain, uncoupling, permeability transition, and/or cell death. Peroxynitrite can cause opening of the permeability transition pore and opening of this pore causes loss of cytochrome c, which in turn might contribute to peroxynitrite-induced inhibition of respiration. Therefore, the inhibition of cytochrome c oxidase by â¢NO may be involved in the physiological and/or pathological regulation of respiration rate, and its affinity for oxygen, which depend on reactive nitrogen species formation, pH, proton motriz force and oxygen supply to tissues.
Assuntos
Respiração Celular/fisiologia , Mitocôndrias/metabolismo , Óxido Nítrico/fisiologia , Animais , Bactérias , Complexo IV da Cadeia de Transporte de Elétrons/antagonistas & inibidores , Humanos , Ácido Peroxinitroso/fisiologia , PlantasRESUMO
Brazilein, a natural small molecule, shows a variety of pharmacological activities, especially on nervous system and immune system. As a potential multifunctional drug, we studied the distribution and the transport behavior and metabolic behavior of brazilein in vivo and in vitro. Brazilein was found to be able to distribute in the mouse brain and transport into neural cells. A metabolite was found in the brain and in the cells. Positive and negative mode-MS/MS and Q-TOF were used to identify the metabolite. MS/MS fragmentation mechanisms showed the methylation occurred at the 10-hydroxyl of brazilein (10-O-methylbrazilein). Further, catechol-O- methyltransferase (COMT) was confirmed as a crucial enzyme correlated with the methylated metabolite generation by molecular docking and pharmacological experiment.
Assuntos
Benzopiranos/metabolismo , Indenos/metabolismo , Neurônios/metabolismo , Animais , Benzopiranos/administração & dosagem , Benzopiranos/química , Benzopiranos/farmacologia , Transporte Biológico/efeitos dos fármacos , Encéfalo/metabolismo , Catecol O-Metiltransferase/química , Catecol O-Metiltransferase/metabolismo , Morte Celular/efeitos dos fármacos , Cromatografia Líquida de Alta Pressão , Complexo IV da Cadeia de Transporte de Elétrons/antagonistas & inibidores , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Indenos/administração & dosagem , Indenos/química , Indenos/farmacologia , Masculino , Metilação/efeitos dos fármacos , Camundongos Endogâmicos ICR , Neurônios/efeitos dos fármacos , Células PC12 , Ratos , Reprodutibilidade dos Testes , Espectrometria de Massas em Tandem , Temperatura , Raios UltravioletaRESUMO
The highly active antiretroviral therapy completely changed the clinical evolution of HIV infection, reducing the morbidity and mortality among human immunodeficiency virus (HIV)-1 infected patients. Therefore, in the present study we evaluated the effect of chronic efavirenz (EFV) and nevirapine (NVP) administration on mitochondrial respiratory chain complexes activities (I, II, II-III, IV) in different brain regions of mice. Mice were orally administered via gavage with EFV 10 mg/kg, NVP 3.3 mg/kg or vehicle (controls) once a day for 36 days. We observed that the complex IV activity was inhibited by both EFV and NVP in cerebral cortex, striatum and hippocampus of mice, but not in cerebellum, as compared to control group. In contrast, chronic EFV and NVP administration did not alter complexes I, II and II-III. We speculated that brain energy metabolism dysfunction could be involved in the CNS-related adverse effects.
Assuntos
Benzoxazinas/farmacologia , Encéfalo/efeitos dos fármacos , Complexo IV da Cadeia de Transporte de Elétrons/antagonistas & inibidores , Nevirapina/farmacologia , Inibidores da Transcriptase Reversa/farmacologia , Alcinos , Animais , Encéfalo/enzimologia , Ciclopropanos , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Masculino , CamundongosRESUMO
Although alpha-mangostin prevents from toxicity associated to oxidative stress, it also promotes apoptotic cell death in cancer cells. Such effects have been associated with mitochondrial membrane depolarization and cytochrome c release. Therefore, the aim of this work was to analyze the potentially harmful effect of this natural compound on relevant parameters of mitochondrial function from normal tissue. Our results showed that alpha-mangostin protected mitochondria from peroxidative damage, but at high concentration, it acted as an uncoupler, reduced dramatically ADP-stimulated respiration and inhibited the activity of respiratory complex IV, making mitochondria prone to permeability transition, which is a mitochondrial player on cell fate.
Assuntos
Metabolismo Energético/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Desacopladores/toxicidade , Xantonas/toxicidade , Animais , Apoptose , Complexo IV da Cadeia de Transporte de Elétrons/antagonistas & inibidores , Membranas Mitocondriais/fisiologia , Consumo de Oxigênio/efeitos dos fármacos , Permeabilidade/efeitos dos fármacos , RatosRESUMO
Malathion is a pesticide used on a large scale and with high potential risk for human exposure. However, it is reasonable to hypothesize that while the malathion is metabolizing reactive oxygen species (ROS) can be generated and subsequently there is onset of an oxidative stress in central nervous system (CNS) structures: hippocampus, cortex, striatum and cerebellum of intoxicated rats due to mitochondrial respiratory chain disfunctions. The present study was therefore undertaken to evaluate malathion-induced lipid peroxidation (LPO), superoxide production from sub-mitochondrial particles and the activity of complexes II and IV of the mitochondrial respiratory chain. Malathion was administered in doses of 25, 50, 100 and 150 mg malathion/kg. After malathion administration LPO increased in hippocampus and striatum. This was accompanied by an increase in the formation of superoxide in submitochondrial particles in the hippocampus. Complex IV suffered significant inhibition of its activity. We could demonstrate in this study that malathion induces oxidative stress and it could be due to inactivation of mitochondrial respiratory complexes.
Assuntos
Encéfalo/efeitos dos fármacos , Respiração Celular/fisiologia , Inseticidas/farmacologia , Malation/farmacologia , Mitocôndrias/metabolismo , Estresse Oxidativo , Animais , Encéfalo/anatomia & histologia , Complexo II de Transporte de Elétrons/antagonistas & inibidores , Complexo II de Transporte de Elétrons/metabolismo , Complexo IV da Cadeia de Transporte de Elétrons/antagonistas & inibidores , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Humanos , Peroxidação de Lipídeos , Masculino , Ratos , Ratos Wistar , Superóxidos/metabolismo , Substâncias Reativas com Ácido Tiobarbitúrico/metabolismoRESUMO
Ethylmalonic aciduria is a common finding in patients affected by short-chain acyl-CoA dehydrogenase (SCAD) deficiency and other diseases characterized by encephalopathy, muscular symptomatology, and lactic acidemia. Considering that the pathophysiological mechanisms of these disorders are practically unknown and that lactic acidosis suggest an impairment of energy production, the objective of the present work was to investigate the in vitro effect of ethylmalonic acid (EMA), at concentrations varying from 0.25 to 5.0 mM, on important parameters of energy metabolism in human skeletal muscle, such as the activities of the respiratory chain complexes and of creatine kinase, which are responsible for most of the ATP produced and transferred inside the cell. We verified that EMA significantly inhibited the activity of complex I-III at concentrations as low as 0.25 mM, complex II-III at 1 mM and higher concentrations, and complex II at the concentration of 5 mM. In contrast, complex IV was not inhibited by the acid. Finally, we observed that the activity of creatine kinase was significantly inhibited by EMA at the concentrations of 1 and 5 mM. These results suggest that EMA compromises energy metabolism in human skeletal muscle. In case the in vitro effects detected in the present study also occur in vivo, it is tempting to speculate that they may contribute, at least in part, to explain the hypotonia/myopathy, as well as the increased concentrations of lactic acid present in the patients affected by illnesses in which EMA accumulates.
Assuntos
Acidose Láctica/metabolismo , Creatina Quinase/metabolismo , Complexo de Proteínas da Cadeia de Transporte de Elétrons/antagonistas & inibidores , Malonatos/farmacologia , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/enzimologia , Trifosfato de Adenosina/metabolismo , Adolescente , Adulto , Complexo de Proteínas da Cadeia de Transporte de Elétrons/metabolismo , Complexo I de Transporte de Elétrons/antagonistas & inibidores , Complexo I de Transporte de Elétrons/metabolismo , Complexo II de Transporte de Elétrons/antagonistas & inibidores , Complexo II de Transporte de Elétrons/metabolismo , Complexo III da Cadeia de Transporte de Elétrons/antagonistas & inibidores , Complexo III da Cadeia de Transporte de Elétrons/metabolismo , Complexo IV da Cadeia de Transporte de Elétrons/antagonistas & inibidores , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Metabolismo Energético/efeitos dos fármacos , Metabolismo Energético/fisiologia , Ativação Enzimática/efeitos dos fármacos , Humanos , Técnicas In VitroRESUMO
Methylmalonic acidemia is an inherited metabolic disorder biochemically characterized by tissue accumulation of methylmalonic acid (MMA) and clinically by progressive neurological deterioration and kidney failure, whose pathophysiology is so far poorly established. Previous studies have shown that MMA inhibits complex II of the respiratory chain in rat cerebral cortex, although no inhibition of complexes I-V was found in bovine heart. Therefore, in the present study we investigated the in vitro effect of 2.5mM MMA on the activity of complexes I-III, II, II-III and IV in striatum, hippocampus, heart, liver and kidney homogenates from young rats. We observed that MMA caused a significant inhibition of complex II activity in striatum and hippocampus (15-20%) at low concentrations of succinate in the medium, but not in the peripheral tissues. We also verified that the inhibitory property of MMA only occurred after exposing brain homogenates for at least 10 min with the acid, suggesting that this inhibition was mediated by indirect mechanisms. Simultaneous preincubation with the nitric oxide synthase inhibitor Nomega-nitro-L-arginine methyl ester (L-NAME) and catalase (CAT) plus superoxide dismutase (SOD) did not prevent MMA-induced inhibition of complex II, suggesting that common reactive oxygen (superoxide, hydrogen peroxide and hydroxyl radical) and nitric (nitric oxide) species were not involved in this effect. In addition, complex II-III (20-35%) was also inhibited by MMA in all tissues tested, and complex I-III only in the kidney (53%) and liver (38%). In contrast, complex IV activity was not changed by MMA in all tissues studied. These results indicate that MMA differentially affects the activity of the respiratory chain pending on the tissues studied, being striatum and hippocampus more vulnerable to its effect. In case our in vitro data are confirmed in vivo in tissues from methylmalonic acidemic patients, it is feasible that that the present findings may be related to the pathophysiology of the tissue damage characteristic of these patients.
Assuntos
Transporte de Elétrons/fisiologia , Inibidores Enzimáticos/metabolismo , Ácido Metilmalônico/metabolismo , Animais , Bovinos , Córtex Cerebral/enzimologia , Complexo I de Transporte de Elétrons/antagonistas & inibidores , Complexo I de Transporte de Elétrons/metabolismo , Complexo II de Transporte de Elétrons/antagonistas & inibidores , Complexo II de Transporte de Elétrons/metabolismo , Complexo III da Cadeia de Transporte de Elétrons/antagonistas & inibidores , Complexo III da Cadeia de Transporte de Elétrons/metabolismo , Complexo IV da Cadeia de Transporte de Elétrons/antagonistas & inibidores , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Rim/enzimologia , Fígado/enzimologia , Miocárdio/enzimologia , Ratos , Ratos Wistar , Extratos de Tecidos/metabolismoRESUMO
L-2-Hydroxyglutaric (LGA) and D-2-hydroxyglutaric (DGA) acids are the characteristic metabolites accumulating in the neurometabolic disorders known as L-2-hydroxyglutaric aciduria and D-2-hydroxyglutaric aciduria, respectively. Although these disorders are predominantly characterized by severe neurological symptoms, the neurotoxic mechanisms of brain damage are virtually unknown. In this study we have evaluated the role of LGA and DGA at concentrations ranging from 0.01 to 5.0 mM on various parameters of energy metabolism in cerebral cortex slices and homogenates of 30-day-old Wistar rats, namely glucose uptake, CO(2) production and the respiratory chain enzyme activities of complexes I to IV. DGA significantly decreased glucose utilization (2.5 and 5.0 mM) by brain homogenates and CO(2) production (5 mM) by brain homogenates and slices, whereas LGA had no effect on either measurement. Furthermore, DGA significantly inhibited cytochrome c oxidase activity (complex IV) (EC 1.9.3.1) in a dose-dependent manner (35-95%) at doses as low as 0.5 mM, without compromising the other respiratory chain enzyme activities. In contrast, LGA did not interfere with these activities. Our results suggest that the strong inhibition of cytochrome c oxidase activity by increased levels of DGA could be related to the neurodegeneration of patients affected by D-2-hydroxyglutaric aciduria.
Assuntos
Córtex Cerebral/enzimologia , Complexo IV da Cadeia de Transporte de Elétrons/antagonistas & inibidores , Glutaratos/farmacologia , Músculo Esquelético/enzimologia , Animais , Dióxido de Carbono/metabolismo , Córtex Cerebral/efeitos dos fármacos , Relação Dose-Resposta a Droga , Complexo III da Cadeia de Transporte de Elétrons/antagonistas & inibidores , Metabolismo Energético , Glucose/metabolismo , Humanos , Técnicas In Vitro , Cinética , Músculo Esquelético/efeitos dos fármacos , Ratos , EstereoisomerismoRESUMO
Although the regulation of mitochondrial respiration and energy production in mammalian tissues has been exhaustively studied and extensively reviewed, a clear understanding of the regulation of cellular respiration has not yet been achieved. In particular, the role of tissue pO2 as a factor regulating cellular respiration remains controversial. The concept of a complex and multisite regulation of cellular respiration and energy production signaled by cellular and intercellular messengers has evolved in the last few years and is still being researched. A recent concept that regulation of cellular respiration is regulated by ADP, O2 and NO preserves the notion that energy demands drive respiration but places the kinetic control of both respiration and energy supply in the availability of ADP to F1-ATPase and of O2 and NO to cytochrome oxidase. In addition, recent research indicates that NO participates in redox reactions in the mitochondrial matrix that regulate the intramitochondrial steady state concentration of NO itself and other reactive species such as superoxide radical (O2-) and peroxynitrite (ONOO-). In this way, NO acquires an essential role as a mitochondrial regulatory metabolite. No exhibits a rich biochemistry and a high reactivity and plays an important role as intercellular messenger in diverse physiological processes, such as regulation of blood flow, neurotransmission, platelet aggregation and immune cytotoxic response.
Assuntos
Mitocôndrias Cardíacas/metabolismo , Mitocôndrias Hepáticas/metabolismo , Óxido Nítrico/metabolismo , Oxigênio/metabolismo , Transporte de Elétrons , Complexo IV da Cadeia de Transporte de Elétrons/antagonistas & inibidores , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Humanos , Mitocôndrias Hepáticas/enzimologiaAssuntos
Mitocôndrias/fisiologia , Óxido Nítrico Sintase/fisiologia , Óxido Nítrico/fisiologia , Animais , Complexo IV da Cadeia de Transporte de Elétrons/antagonistas & inibidores , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Humanos , Potenciais da Membrana/fisiologia , Mitocôndrias/metabolismo , Óxido Nítrico/metabolismo , Óxido Nítrico Sintase/metabolismo , Consumo de Oxigênio , Ácido Peroxinitroso/metabolismo , Espécies Reativas de Oxigênio/metabolismoAssuntos
Animais , Humanos , Mitocôndrias/fisiologia , Óxido Nítrico Sintase/fisiologia , Óxido Nítrico/fisiologia , Ácido Peroxinitroso/metabolismo , Complexo IV da Cadeia de Transporte de Elétrons/antagonistas & inibidores , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Mitocôndrias/metabolismo , Consumo de Oxigênio , Óxido Nítrico Sintase/metabolismo , Óxido Nítrico/metabolismo , Potenciais da Membrana/fisiologiaRESUMO
1. The effect of acute cyanide administration to mice in a lethal and a non-lethal dose and the anti-cyanide effect of S-adenosyl-L-methionine (SAM) and thiosulphate were investigated. 2. The poisoning action was determined by measuring cytochrome oxidase, rhodanese and delta-aminolevulinic acid dehydratase (ALA-D) activity. 3. The toxic metabolizing degree was investigated by measuring plasma and urine thiocyanate levels. 4. The state of the sulfane sulfur pool was investigated by determining cyanide labile-sulfur levels. 5. These results support the belief that rhodanese plays a fundamental role in the detoxification process only when high levels of cyanide are administered.
Assuntos
Cianetos/toxicidade , Animais , Cianetos/administração & dosagem , Cianetos/sangue , Complexo IV da Cadeia de Transporte de Elétrons/antagonistas & inibidores , Dose Letal Mediana , Camundongos , Sintase do Porfobilinogênio/metabolismo , Proteínas/metabolismo , S-Adenosilmetionina/farmacologia , Radioisótopos de Enxofre , Tiocianatos/sangue , Tiocianatos/urina , Tiossulfato Sulfurtransferase/antagonistas & inibidores , Tiossulfatos/sangue , Tiossulfatos/farmacologiaRESUMO
1. Several sub-lethal doses of cyanide were assayed with the aim of obtaining significant differences in the parameters studied. A dose of 4 mg/kg s.c. was selected. 2. Present studies were carried out to determine the time dependence of the effects produced by s.c. administration of a single dose of potassium cyanide as well as the recovery time of some of the toxicity indicative parameters. 3. It was found that cyanide effects continued for at least 3 days; after the parameters had recovered normal values.