Cytokines and the nervous system: The relationship between seizures and epilepsy [Citocinas y sistema nervioso: Relaci�n con crisis convulsivas y epilepsia]

Introduction. The immune system and the peripheral and central nervous system are in constant communication by means of messengers and signalling molecules released, such as cytokines, neuropeptides, neurohormones and neuro-transmitters, among others. Seizures are defined as the transitory appearance of signs and symptoms that trigger an abnormally excessive neuronal activity in the brain. Following seizures the generation of a neuroinflammatory process has been observed to occur, with the consequent release of proinflammatory cytokines and inflammation-mediating molecules, which make the patient more prone to epilepsy. Aim. To offer evidence suggesting and supporting the role of cytokines in the appearance of seizures and in epilepsy, since these molecules have proven to have dual properties. Development. The central nervous system, by means of the blood-brain barrier, restricts the flow of activated cells and inflammation mediators released from the peripheral system towards the brain parenchyma. Moreover, there is also another series of mechanisms that contributes to the 'selective and modified' immunity of the central nervous system. The purpose of all this series of events is to limit the responses of the immune system at central level, although it has been shown that in the central nervous system they are permanently under the control and regulation of the immune system. Conclusions. Cytokines in epilepsy play a dual role with pro- and anti-convulsive properties. Seizures do not induce the expression of cytokines only inside the brain, but also peripherally. � 2013 Revista de Neurolog�a

Cytokines and the nervous system: The relationship between seizures and epilepsy [Citocinas y sistema nervioso: Relación con crisis convulsivas y epilepsia]

Introduction. The immune system and the peripheral and central nervous system are in constant communication by means of messengers and signalling molecules released, such as cytokines, neuropeptides, neurohormones and neuro-transmitters, among others. Seizures are defined as the transitory appearance of signs and symptoms that trigger an abnormally excessive neuronal activity in the brain. Following seizures the generation of a neuroinflammatory process has been observed to occur, with the consequent release of proinflammatory cytokines and inflammation-mediating molecules, which make the patient more prone to epilepsy. Aim. To offer evidence suggesting and supporting the role of cytokines in the appearance of seizures and in epilepsy, since these molecules have proven to have dual properties. Development. The central nervous system, by means of the blood-brain barrier, restricts the flow of activated cells and inflammation mediators released from the peripheral system towards the brain parenchyma. Moreover, there is also another series of mechanisms that contributes to the 'selective and modified' immunity of the central nervous system. The purpose of all this series of events is to limit the responses of the immune system at central level, although it has been shown that in the central nervous system they are permanently under the control and regulation of the immune system. Conclusions. Cytokines in epilepsy play a dual role with pro- and anti-convulsive properties. Seizures do not induce the expression of cytokines only inside the brain, but also peripherally. © 2013 Revista de Neurología

Effect of brief constant darkness and illumination on mitochondrial respiratory control of the pineal gland, Harderian gland, spleen and thymus of adult rat [Efeitos da escuridão e da luminosidade breve e constante no controle da respiração mitocondrial das glândulas pineal, Harderiana, baço e timo]

Background and objectives: Constant environmental conditions can lead to changes in the synthesis of melatonin. In vitro studies have shown that this hormone modulates the efficiency of mitochondrial respiration. Therefore, this work examined whether the efficiency of mitochondrial respiration changes in rats that have been subjected to constant illumination or darkness for a short period. Methods: Rats were randomly distributed in three groups: Control, Constant Illumination (72 hours) and Constant Darkness (72 hours). Upon completion of treatment, rats were sacrificed and mitochondria from the pineal gland, Harderian gland, thymus and spleen were isolated. Subsequently, mitochondrial respiratory control was quantified from the removed tissues in the three experimental groups. Results: Our findings show that brief treatments of continued illumination or continued darkness had no significant effect on mitochondrial respiratory control in spleen, thymus or Harderian glands. In contrast, we observed a slight increase in mitochondrial respiratory control in the pineal gland of animals exposed to constant illumination. Conclusions: Our results suggest that brief treatment with continuous light or darkness does not have a significant effect on the efficiency of mitochondrial activity in spleen, thymus or Harderian gland. This is probably due to the endogenous circadian rhythms that tightly regulate mitochondrial enzymatic activity in these tissues

Effect of brief constant darkness and illumination on mitochondrial respiratory control of the pineal gland, Harderian gland, spleen and thymus of adult rat [Efeitos da escuridão e da luminosidade breve e constante no controle da respiração mitocondrial das glándulas pineal, Harderiana, baño e timo]

Background and objectives: Constant environmental conditions can lead to changes in the synthesis of melatonin. In vitro studies have shown that this hormone modulates the efficiency of mitochondrial respiration. Therefore, this work examined whether the efficiency of mitochondrial respiration changes in rats that have been subjected to constant illumination or darkness for a short period. Methods: Rats were randomly distributed in three groups: Control, Constant Illumination (72 hours) and Constant Darkness (72 hours). Upon completion of treatment, rats were sacrificed and mitochondria from the pineal gland, Harderian gland, thymus and spleen were isolated. Subsequently, mitochondrial respiratory control was quantified from the removed tissues in the three experimental groups. Results: Our findings show that brief treatments of continued illumination or continued darkness had no significant effect on mitochondrial respiratory control in spleen, thymus or Harderian glands. In contrast, we observed a slight increase in mitochondrial respiratory control in the pineal gland of animals exposed to constant illumination. Conclusions: Our results suggest that brief treatment with continuous light or darkness does not have a significant effect on the efficiency of mitochondrial activity in spleen, thymus or Harderian gland. This is probably due to the endogenous circadian rhythms that tightly regulate mitochondrial enzymatic activity in these tissues

Relationship between inflammation and oxidative stress and its effect on multiple sclerosis

Introduction: This paper highlights the relationship of inflammation and oxidative stress as damage mechanisms of Multiple Sclerosis (MS), considered an inflammatory and autoimmune disease. Development: The oxidative stress concept has been defined by an imbalance between oxidants and antioxidants in favor of the oxidants. There is necessary to do physiological functions, like the respiration chain, but in certain conditions, the production of reactive species overpassed the antioxidant systems, which could cause tissue damage. On the other hand, it is well established that inflammation is a complex reaction in the vascularized connective tissue in response to diverse stimuli. However, an unregulated prolonged inflammatory process also can induce tissue damage. Conclusion: Both inflammation and oxidative stress are interrelated since one could promote the other, leading to a toxic feedback system, which contributes to the inflammatory and demyelination process in MS. Resumen: Introducción: Este trabajo destaca la relación de la inflamación y el estrés oxidativo como mecanismos de daño de la esclerosis múltiple, considerada enfermedad inflamatoria y autoinmune. Desarrollo: El concepto de estrés oxidativo se ha definido por un desequilibrio entre oxidantes y antioxidantes a favor de los oxidantes. Es necesario para realizar funciones fisiológicas, como la cadena respiratoria, pero en ciertas condiciones la producción de especies reactivas sobrepasaba los sistemas antioxidantes, lo que podría causar daño tisular. Por otro lado, está establecido que la inflamación es una reacción compleja en el tejido conectivo vascularizado en respuesta a diversos estímulos, pero un proceso inflamatorio prolongado no regulado también puede inducir daño tisular. Conclusión: Tanto la inflamación como el estrés oxidativo están interrelacionados entre sí, ya que uno de ellos podría promover al otro, dando lugar a un sistema de retroalimentación tóxico, que contribuye al desarrollo del proceso inflamatorio y desmielinizante en la esclerosis múltiple

Effects of melatonin on plasma levels of TNF-?, IL-1 and IL-6 in mice after lipopolysaccharide administration

Bidirectional dependence exists between the immune and neuroendocrine systems, with common chemical messengers, such as melatonin (MLT), having immunoregulatory functions in some mechanisms of endotoxic shock. We used 10-12-week-old female Balb/c mice, with an average weight of 22-24 g, maintained under a 12 h light-dark cycle. The LD100 of lipopolysaccharide (LPS) was determined to be 10 mg/kg (ip.) from a dose-response curve. Pretreatment with MLT (10 mg/kg ip.) increased survival by 60%, decreased plasma TNF-?? and increased IL-1. No significant changes were observed in levels of plasma IL-6. Zapotitlán 2005 Taylor & Francis Group Ltd

Antioxidant activity of tryptophan in rats under experimental endotoxic shock

Tryptophan (TRP), the precursor of the scavenger or immunomodulator molecules melatonin (MLT) and picolinic acid, can be found in the diet; and could be an alternative nutritional supplement used to regulate the immune response in the generation of free radicals. In an experimental model, the systemic administration of lipopolysaccharide (LPS), to promote the synthesis of pro-inflammatory cytokines, reactive oxygen species, and antioxidant enzymes, was performed on adult female, pregnant and lactating rats fed with a diet of TRP content (0.5 mg/100 g protein). Lung tissue was evaluated for levels of the products of lipoperoxidation (LPO's), malonaldehyde (MDA) and 4-hydroxy alkenals (4-HDA); nitrites (NO2), glutathione peroxidase (Gpx) enzyme activity, and the serum concentration of interferon-gamma (IFN-?), which were measured in the following groups: control (CTRL), LPS, MLT, TRP, LPS plus MLT (LPS + MLT), and LPS plus TRP (LPS + TRP). Results showed that the lung tissue levels of MDA and 4-HDA in the LPS + TRP group were significantly lower than in the TRP group. Statistically significant differences were not observed in nitric oxide levels among the groups LPS + MLT and LPS + TRP compared to the group under endotoxic shock (LPS). The Gpx enzyme activity was modified in the LPS + MLT vs the LPS group, but the difference was not statistically significant. The LPS + MLT group showed a smaller serum concentration (98%) of IFN-? than the LPS group. Statistically significant differences were not observed among the animals of the LPS + TRP and the LPS groups. © 2009 Elsevier Masson SAS. All rights reserved

The orbital harderian gland of the male atlantic bottlenose dolphin (Tursiops truncatus): A morphological study

Summary The ultrastructure of the Atlantic Bottlenose dolphin Harderian gland (HG) has been described but some questions remain unanswered. The purpose of this work was to define the gland's structure, ultrastructure and the differences between cells (types I and II) of the male dolphin using optic, fluorescence and electron transmission microscopy. Three different cells were observed under optic and fluorescence microscopic examination, while only two cell types (types I and II) were distinguished by electron transmission microscopy. Type I (oval nuclear envelope) exhibited three different cell populations and type II (indented nuclear envelope) exhibited two different cell populations. Although, we observed both types of vesicles in both types of cells they differed, principally, in quantity. The glands also possessed prominent duct systems, with three orders of complexity. The dolphin orbital HG appears to function as a mixed heterologous gland with two types of cells that exhibit both types of vesicles and other distinguishable differences. © 2007 The Authors. Journal compilation 2007 Blackwell Verlag

Monosodium glutamate-induced damage in liver and kidney: A morphological and biochemical approach

It has been demonstrated that high concentrations of monosodium glutamate in the central nervous system induce neuronal necrosis and damage in retina and circumventricular organs. In this model, the monosodium glutamate is used to induce an epileptic state; one that requires highly concentrated doses. The purpose of this study was to evaluate the toxic effects of the monosodium glutamate in liver and kidney after an intra-peritoneal injection. For the experiment, we used 192 Wistar rats to carry out the following assessments: a) the quantification of the enzymes alanine aminotransferase and aspartate aminotransferase, b) the quantification of the lipid peroxidation products and c) the morphological evaluation of the liver and kidney. During the experiment, all of these assessments were carried out at 0, 15, 30 and 45 min after the intra-peritoneal injection. In the rats that received monosodium glutamate, we observed increments in the concentration of alanine aminotransferase and aspartate aminotransferase at 30 and 45 min. Also, an increment of the lipid peroxidation products, in kidney, was exhibited at 15, 30 and 45 min while in liver it was observed at 30 and 45 min. Degenerative changes were observed (edema-degeneration-necrosis) at 15, 30 and 45 min. Zapotitlán 2006 Elsevier SAS. All rights reserved