Impairment of energy metabolism in hippocampus of rats subjected to chemically-induced hyperhomocysteinemia

AbstractHomocystinuria is an inherited metabolic disease biochemically characterized by tissue accumulation of homocysteine (Hcy). Mental retardation, ischemia and other neurological features, whose mechanisms are still obscure are common symptoms in homocystinuric patients. In this work, we investigated the effect of Hcy administration in Wistar rats on some parameters of energy metabolism in the hippocampus, a cerebral structure directly involved with cognition. The parameters utilized were 14CO2 production, glucose uptake, lactate release and the activities of succinate dehydrogenase and cytochrome c oxidase (COX). Chronic hyperhomocysteinemia was induced by subcutaneous administration of Hcy twice a day from the 6th to the 28th day of life in doses previously determined in our laboratory. Control rats received saline in the same volumes. Rats were killed 12 h after the last injection. Results showed that Hcy administration significantly diminished 14CO2 production and glucose uptake, as well as succinate dehydrogenase and COX activities. It is suggested that impairment of brain energy metabolism may be related to the neurological symptoms present in homocystinuric patients

Fluvoxamine alters the activity of energy metabolism enzymes in the brain

Objective: Several studies support the hypothesis that metabolism impairment is involved in the pathophysiology of depression and that some antidepressants act by modulating brain energy metabolism. Thus, we evaluated the activity of Krebs cycle enzymes, the mitochondrial respiratory chain, and creatine kinase in the brain of rats subjected to prolonged administration of fluvoxamine. Methods: Wistar rats received daily administration of fluvoxamine in saline (10, 30, and 60 mg/kg) for 14 days. Twelve hours after the last administration, rats were killed by decapitation and the prefrontal cortex, cerebral cortex, hippocampus, striatum, and cerebellum were rapidly isolated. Results: The activities of citrate synthase, malate dehydrogenase, and complexes I, II-III, and IV were decreased after prolonged administration of fluvoxamine in rats. However, the activities of complex II, succinate dehydrogenase, and creatine kinase were increased. Conclusions: Alterations in activity of energy metabolism enzymes were observed in most brain areas analyzed. Thus, we suggest that the decrease in citrate synthase, malate dehydrogenase, and complexes I, II-III, and IV can be related to adverse effects of pharmacotherapy, but long-term molecular adaptations cannot be ruled out. In addition, we demonstrated that these changes varied according to brain structure or biochemical analysis and were not dose-dependent

AVALIAÇÃO DO EFEITO DO EXTRATO HIDROALCOÓLICO DE Zollernia ilicifolia (FABACEAE) COMO GASTROPROTETOR EM RATOS

A Zollernia ilicifolia (Fabaceae) é uma planta nativa da Floresta Tropical Atlântica, e utilizada principalmente contra úlceras e problemas estomacais. O objetivo deste estudo foi avaliar o efeito gastroprotetor do extrato hidroalcoólico de Zollernia ilicifolia em ratos, através dos complexos da cadeia respiratória mitocondrial e da análise histológica do estômago dos ratos submetidos a um modelo animal de gastrite induzido por indometacina. Ratos Wistar adultos foram tratados com extrato e água destilada (controle), por meio de gavagem. Os animais foram submetidos a jejum por 24h; após esse período foi administrado indometacina em dois grupos e água destilada nos outros dois grupos. Os animais foram eutanasiados após 6 horas por decapitação para exerese do estômago e observação das lesões gástricas e posteriormente para avaliação da cadeia respiratória mitocondrial. Os resultados mostraram que o extrato não foi capaz de prevenir o aumento da lesão induzida pela indometacina e também pode ser observado que o extrato não pôde reverter à inibição da atividade da cadeia respiratória mitocondrial

AVALIAÇÃO DO EFEITO DO EXTRATO HIDROALCOÓLICO DE Zollernia ilicifolia (FABACEAE) COMO GASTROPROTETOR EM RATOS

A Zollernia ilicifolia (Fabaceae) é uma planta nativa da Floresta Tropical Atlântica, e utilizada principalmente contra úlceras e problemas estomacais. O objetivo deste estudo foi avaliar o efeito gastroprotetor do extrato hidroalcoólico de Zollernia ilicifolia em ratos, através dos complexos da cadeia respiratória mitocondrial e da análise histológica do estômago dos ratos submetidos a um modelo animal de gastrite induzido por indometacina. Ratos Wistar adultos foram tratados com extrato e água destilada (controle), por meio de gavagem. Os animais foram submetidos a jejum por 24h; após esse período foi administrado indometacina em dois grupos e água destilada nos outros dois grupos. Os animais foram eutanasiados após 6 horas por decapitação para exerese do estômago e observação das lesões gástricas e posteriormente para avaliação da cadeia respiratória mitocondrial. Os resultados mostraram que o extrato não foi capaz de prevenir o aumento da lesão induzida pela indometacina e também pode ser observado que o extrato não pôde reverter à inibição da atividade da cadeia respiratória mitocondrial

Gastrin-Releasing Peptide Receptor Antagonism Induces Protection from Lethal Sepsis: Involvement of Toll-like Receptor 4 Signaling

In sepsis, toll-like receptor (TLR)-4 modulates the migration of neutrophils to infectious foci, favoring bacteremia and mortality. In experimental sepsis, organ dysfunction and cytokines released by activated macrophages can be reduced by gastrin-releasing peptide (GRP) receptor (GRPR) antagonist RC-3095. Here we report a link between GRPR and TLR-4 in experimental models and in sepsis patients. RAW 264.7 culture cells were exposed to lipopolysaccharide (LPS) or tumor necrosis factor (TNF)-alpha and RC-3095 (10 ng/mL), Male Wistar rats were subjected to cecal ligation and puncture (CLP), and RC-3095 was administered (3 mg/kg, subcutaneously); after 6 h, we removed the blood, bronchoalveolar lavage, peritoneal lavage and lung. Human patients with a clinical diagnosis of sepsis received a continuous infusion with RC-3095 (3 mg/kg, intravenous) over a period of 12 h, and plasma was collected before and after RC-3095 administration and, in a different set of patients with systemic inflammatory response syndrome (SIRS) or sepsis. GRP plasma levels were determined. RC-3095 inhibited TLR-4, extracellular-signal-related kinase (ERK)-1/2, Jun NH2-terminal kinase (JNK) and Akt and decreased activation of activator protein 1 (AP-1), nuclear factor (NF)-kappa B and interleukin (IL)-6 in macrophages stimulated by LPS. It also decreased IL-6 release from macrophages stimulated by TNF-alpha. RC-3095 treatment in CLP rats decreased lung TLR-4, reduced the migration of cells to the lung and reduced systemic cytokines and bacterial dissemination. Patients with sepsis and systemic inflammatory response syndrome have elevated plasma levels of GRP which associates with clinical outcome in the sepsis patients. These findings highlight the role of GRPR signaling in sepsis outcome and the beneficial action of GRPR antagonists in controlling the inflammatory response in sepsis through a mechanism involving at least inhibition of TLR-4 signaling. Online address: http://www.molmed.org doi: 10.2119/molmed.2012.0008