Glutamate reduces glucose utilization while concomitantly enhancing AQP9 and MCT2 expression in cultured rat hippocampal neurons

The excitatory neurotransmitter glutamate has been reported to have a major impact on brain energy metabolism. Using primary cultures of rat hippocampal neurons, we observed that glutamate reduces glucose utilization in this cell type, suggesting alteration in mitochondrial oxidative metabolism. the aquaglyceroporin AQP9 and the monocarboxylate transporter MCT2, two transporters for oxidative energy substrates, appear to be present in mitochondria of these neurons. Moreover, they not only co-localize but they interact with each other as they were found to co-immunoprecipitate from hippocampal neuron homogenates. Exposure of cultured hippocampal neurons to glutamate 100 mu M for 1 h led to enhanced expression of both AQP9 and MCT2 at the protein level without any significant change at the mRNA level. in parallel, a similar increase in the protein expression of LDHA was evidenced without an effect on the mRNA level. These data suggest that glutamate exerts an influence on neuronal energy metabolism likely through a regulation of the expression of some key mitochondrial proteins.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Swiss government scholarshipSwiss National FoundationUniversidade Federal de São Paulo, Dept Fisiol, São Paulo, BrazilUniv Lausanne, Dept Physiol, Lab Neuroenerget, Lausanne, SwitzerlandUniversidade Federal de São Paulo, Dept Fisiol, São Paulo, BrazilFAPESP: 10/50349-1Swiss government scholarship: 2011.0188Swiss National Foundation: 31003A-125063Swiss National Foundation: 31003A-140957Web of Scienc

Is Mossy Fiber Sprouting a Potential Therapeutic Target for Epilepsy?

Mesial temporal lobe epilepsy (MTLE) caused by hippocampal sclerosis is one of the most frequent focal epilepsies in adults. It is characterized by focal seizures that begin in the hippocampus, sometimes spread to the insulo-perisylvian regions and may progress to secondary generalized seizures. Morphological alterations in hippocampal sclerosis are well defined. Among them, hippocampal sclerosis is characterized by prominent cell loss in the hilus and CA1, and abnormal mossy fiber sprouting (granular cell axons) into the dentate gyrus inner molecular layer. In this review, we highlight the role of mossy fiber sprouting in seizure generation and hippocampal excitability and discuss the response of alternative treatment strategies in terms of MFS and spontaneous recurrent seizures in models of TLE (temporal lobe epilepsy)

Facial nerve identification with fluorescent dye in rats

PURPOSE: The parotidectomy technique still has an elevated paresis and paralysis index, lowering patient life's quality. The correct identification of the facial nerve can prevent nerve damage. Fluorescent dye identifies nerves in experimental studies but only few articles focused its use on facial nerve study in parotidectomies. We aimed to stain the rat facial nerve with fluorescent dye to facilitate visualization and dissection in order to prevent injuries. METHODS: Forty adult male Wistar rats were submitted to facial injection of saline solution (Gsf-control group, 10) or fluorescent dye solution (Gdye group, 30) followed by parotidectomy preserving the facial nerve, measuring the time for localization and facility of localization (LocTime and LFN). Nerve function was assessed using the Vibrissae Movements (PMV) and Eyelid Closure Motion (PFP) scores. RESULTS: Nerve localization was faster in Gdye group, with 83% Easy LFN rate. The Gdye group presented with low nerve injury degree and better PMV and PFP scores, with high sensitivity and accuracy. CONCLUSIONS: This experimental method of facial nerve fluorescence was effective for intraoperative nerve visualization, identification and preservation. The technique may be used in future facial nerve studies, translated to humans, contributing to the optimization of parotid surgery in the near future.CAPESUniv Fed Sao Paulo UNIFESP, Dept Otorhinolaryngol Head & Neck Surg, Head & Neck Surg Div, Sao Paulo, BrazilUniv Fed Sao Paulo, Dept Otorhinolaryngol Head & Neck Surg, Sao Paulo, SP, BrazilUniv Fed Sao Paulo, Neurophysiol Lab, Dept Physiol, Sao Paulo, SP, BrazilUniv Fed Sao Paulo, Expt Models Dev Ctr CEDEME, Sao Paulo, SP, BrazilUniv Fed Sao Paulo, Transgen Lab, Sao Paulo, SP, BrazilUniv Fed Sao Paulo, Neurophysiol Lab, Dept Physiol, Postgrad Program Neurosci & Neurol, Sao Paulo, SP, BrazilUniv Fed Sao Paulo UNIFESP, Dept Otorhinolaryngol Head & Neck Surg, Head & Neck Surg Div, Sao Paulo, BrazilUniv Fed Sao Paulo, Dept Otorhinolaryngol Head & Neck Surg, Sao Paulo, SP, BrazilUniv Fed Sao Paulo, Neurophysiol Lab, Dept Physiol, Sao Paulo, SP, BrazilUniv Fed Sao Paulo, Expt Models Dev Ctr CEDEME, Sao Paulo, SP, BrazilUniv Fed Sao Paulo, Transgen Lab, Sao Paulo, SP, BrazilUniv Fed Sao Paulo, Neurophysiol Lab, Dept Physiol, Postgrad Program Neurosci & Neurol, Sao Paulo, SP, BrazilWeb of Scienc

Anatomical study of a temporal bone from a non-human primate (Callithrix sp)

The search for experimental (animal) models is essential to the development of clinical studies. AIM: To demonstrate, by means of micro dissection techniques, the anatomical structures of temporal bones from the primate Callithrix sp. STUDY DESIGN: Experimental. METHODS: Dissection of temporal bone structures of Callithrix sp and photographic documentation. RESULTS: We identified the main constituents of the temporal bone (external, medium and inner ear and facial nerve). CONCLUSION: The non-human primate Callithrix sp. is an adequate experimental model for the studies of temporal bone structures given its close anatomical similarities to that found in humans.A busca por modelos experimentais constitui passo fundamental para o avanço da medicina. OBJETIVO: Demonstrar, através da dissecção com técnicas microcirúrgicas, as estruturas anatômicas do osso temporal do primata Callithrix sp. FORMA DE ESTUDO: Experimental. MÉTODO: Dissecção de ossos temporais de Callithrix sp e documentação fotográfica. RESULTADOS: Identificamos as principais estruturas do osso temporal (orelhas externa, média e interna, e nervo facial). CONCLUSÃO: O primata não-humano Callithrix sp representa aparentemente um modelo viável para o estudo do osso temporal uma vez que apresenta alta similaridade anatômica com humanos.UNIFESP-EPMUNIFESP Departamento de FisiologiaUniversidade Federal São Paulo Departamento OtorrinolaringologiaUNIFESP, EPMUNIFESP, Depto. de FisiologiaSciEL

Participation of bone marrow-derived cells in hippocampal vascularization after status epilepticus

Purpose: Diseases such as temporal lobe epilepsy, brain trauma and stroke can induce endothelial cell proliferation and angiogenesis in specific brain areas. During status epilepticus (SE), bone marrow-derived cells are able to infiltrate and proliferate, dramatically increasing at the site of injury. However, it is still unclear whether these cells directly participate in vascular changes induced by SE.Method: To investigate the possible role of bone marrow-derived cells in angiogenesis after seizures, we induced SE by pilocarpine injection in previously prepared chimeric mice. Mice were euthanized at 8 h, 7 d or 15 d after SE onset.Results: Our results indicated that SE modified hippocampal vascularization and induced angiogenesis. Further, bone marrow-derived GFP(+) cells penetrated through the parenchyma and participated in the formation of new vessels after SE. We detected bone marrow-derived cells closely associated with vessels in the hippocampus, increasing the density of blood vessels that had decreased immediately after pilocarpine-induced SE.Conclusion: We conclude that epileptic seizures directly affect vascularization in the hippocampus mediated by bone marrow-derived cells in a time-dependent manner. (C) 2014 British Epilepsy Association. Published by Elsevier B.V. All rights reserved.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Universidade Federal de São Paulo, Dept Physiol, BR-04023062 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Physiol, BR-04023062 São Paulo, BrazilWeb of Scienc

Effects of Sulpiride on True and False Memories of Thematically Related Pictures and Associated Words in Healthy Volunteers

Episodic memory, working memory, emotional memory, and attention are subject to dopaminergic modulation. However, the potential role of dopamine on the generation of false memories is unknown. This study defined the role of the dopamine D-2 receptor on true and false recognition memories. Twenty-four young, healthy volunteers ingested a single dose of placebo or 400 mg oral sulpiride, a dopamine D-2-receptor antagonist, just before starting the recognition memory task in a randomized, double-blind, and placebo-controlled trial. The sulpiride group presented more false recognitions during visual and verbal processing than the placebo group, although both groups had the same indices of true memory. These findings demonstrate that dopamine D-2 receptors blockade in healthy volunteers can specifically increase the rate of false recognitions. The findings fit well the two-process view of causes of false memories, the activation/monitoring failures model.Univ Fed Sao Paulo, Dept Psychobiol, Sao Paulo, BrazilAssociacao Fundo Incent Pesquisa, Sao Paulo, BrazilUniv Fed Sao Paulo, Dept Physiol, Sao Paulo, BrazilUniv Fed Sao Paulo, Dept Psychobiol, Sao Paulo, BrazilWeb of Scienc

Microinjection of GABAergic agents into the anterior nucleus of the thalamus modulates pilocarpine-induced seizures and status epilepticus

The anterior nucleus of the thalamus (AN) has been suggested as a potential target for seizure modulation in animal models and patients with refractory epilepsy. We investigate whether microinjections of GABAergic agonists into the AN were protective against pilocarpine-induced generalized seizures and status epilepticus (SE). Rats were treated with bilateral AN injections of muscimol (160 or 80 nmol), bicuculline (15 nmol), or saline (controls) 20 min prior to pilocarpine administration (350 mg/kg i.p.). Electrographic recordings were used to confirm seizure activity. We found that pretreatment with AN muscimol 160 nmol increased the latency to seizures and SE by 2.5-3.0-fold. This dose however was associated with side effects, particularly hypotonia. AN bicuculline was proconvulsant, whereas no major effect was observed after muscimol 80 nmol injections. the percentage of animals that developed SE was similar across groups. Overall, microinjection of high doses of muscimol into the AN delayed the occurrence of pilocarpine-induced seizures and SE but was not able to prevent these events. (C) 2010 British Epilepsy Association. Published by Elsevier B.V. All rights reserved.Toronto Western Hosp, Div Neurosurg, Toronto, ON M5T 2S8, CanadaUniversidade Federal de São Paulo, Dept Physiol, São Paulo, BrazilToronto Western Hosp, Div Neurol, Toronto, ON M5T 2S8, CanadaUniversidade Federal de São Paulo, Dept Psychobiol, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Physiol, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Psychobiol, São Paulo, BrazilWeb of Scienc

Social isolation disrupts hippocampal neurogenesis in young non-human primates

Social relationships are crucial for the development and maintenance of normal behavior in non-human primates. Animals that are raised in isolation develop abnormal patterns of behavior that persist even when they are later reunited with their parents. in rodents, social isolation is a stressful event and is associated with a decrease in hippocampal neurogenesis but considerably less is known about the effects of social isolation in non-human primates during the transition from adolescence to adulthood. To investigate how social isolation affects young marmosets, these were isolated from other members of the colony for 1 or 3 weeks and evaluated for alterations in their behavior and hippocampal cell proliferation. We found that anxiety-related behaviors like scent-marking and locomotor activity increased after social isolation when compared to baseline levels. in agreement, grooming an indicative of attenuation of tension was reduced among isolated marmosets. These results were consistent with increased cortisol levels after 1 and 3 weeks of isolation. After social isolation (1 or 3 weeks), reduced proliferation of neural cells in the subgranular zone of dentate granule cell layer was identified and a smaller proportion of BrdU-positive cells underwent neuronal fate (doublecortin labeling). Our data is consistent with the notion that social deprivation during the transition from adolescence to adulthood leads to stress and produces anxiety-like behaviors that in turn might affect neurogenesis and contribute to the deleterious consequences of prolonged stressful conditions.Universidade Federal de São Paulo, Dept Fisiol, BR-04023062 São Paulo, BrazilUniv Fed Rio Grande do Norte, Dept Fisiol, BR-59072970 Natal, RN, BrazilUniv Fed Rural Rio de Janeiro, Dept Ciencias Fisiol, Rio de Janeiro, BrazilUniversidade Federal de São Paulo, Dept Fisiol, BR-04023062 São Paulo, BrazilWeb of Scienc

The il1β have a protective action in the acute phase of the pilocarpine-induced epilepsy model

INTRODUCTION: There is contradictory information regarding the of effects il1β and il1rn in epilepsy. We aimed to evaluate the effect of silencing both genes in the acute phase of the pilocarpine-induced epilepsy model. METHODS: We used RNA interference in order to achieve gene silencing. RESULTS: We obtained significant gene silencing in the central nervous system. In addition, we observed phenotypic effects including differences in mortality rates of animals 5 days after pilocarpine injections. CONCLUSION: Our results indicate that il1β seems to have a protective effect in the acute phase of the pilocarpine-induced epilepsy model.INTRODUÇÃO: Existem contradições na literatura quanto aos efeitos dos genes il1β e il1rn nas epilepsias. Nosso objetivo foi avaliar os efeitos do silenciamento desses dois genes na fase aguda do modelo de epilepsia induzido pela pilocarpina. MÉTODOS: Para alterar a expressão dos genes il1β e il1rn utilizamos a técnica de interferência por RNA. RESULTADOS: Obtivemos taxas de silenciamento significativas para os dois genes no sistema nervoso central. Observamos efeitos fenotípicos significativos, incluindo a alteração na taxa de mortalidade dos animais 5 dias após a indução do modelo. CONCLUSÕES: A il1β parece exercer um papel protetor na fase aguda do modelo de epilepsia induzido pela pilocarpina.UNICAMP FCM Departamento de Genética MedicaUSP Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto Departamento de BiologiaUNICAMP Centro Multidisciplinar de Investigação BiológicaUSP IFSC Departamento de Física e BioinformáticaUNIFESP-EPM Departamento de FisiologiaUNIFESP-EPM Departamento de Neurologia e NeurocirurgiaUNICAMP FCM Departamento de Clínica MédicaUNICAMP FCM Departamento de NeurologiaUNIFESP, EPM, Depto. de FisiologiaUNIFESP, EPM Depto. de Neurologia e NeurocirurgiaSciEL