Pharmacological properties of purinergic receptors and their effects on proliferation and induction of neuronal differentiation of P19 embryonal carcinoma cells

We have used P19 embryonal carcinoma cells as in vitro model for early neurogenesis to study ionotropic P2X and metabotropic P2Y receptor-induced Ca2+ transients and their participation in induction of proliferation and differentiation. In embryonic P19 cells, P2Y(1), P2Y(2) and P2X(4) receptors or P2X-heteromultimers with similar P2X4 pharmacology were responsible for ATP and ATP analogue-induced Ca2+ transients. In neuronal-differentiated cells, P2Y(2), P2Y(6), P2X(2) and possibly P2X(2)/P2X(6) heteromeric receptors were the major mediators of the elevations in intracellular free calcium concentration [Ca2+](i). We have collected evidence for the involvement of metabotropic purinergic receptors in proliferation induction of undifferentiated and neural progenitor cells by using a BrdU-incorporation assay. ATP-, UTP-, ADP-, 2-MeS-ATP- and ADP-beta S-induced proliferation in P19 cells was mediated by P2Y, and P2Y2 receptors as judged from pharmacological profiles of receptor responses. ATP-provoked acceleration of neuronal differentiation, determined by analysis of nestin and neuron-specific enolase gene and protein expression, also resulted from P2Y, and P2Y2 receptor activation. Proliferation- and differentiation-induction involved the activation of inositol-trisphosphate sensitive intracellular Ca2+ stores. (C) 2008 ISDN. Published by Elsevier Ltd. All rights reserved.

Mechanism of acetylcholine-induced calcium signaling during neuronal differentiation of P19 embryonal carcinoma cells in vitro

Muscarinic (mAChRs) and nicotinic acetylcholine receptors (nAChRs) are involved in various physiological processes, including neuronal development. We provide evidence for expression of functional nicotinic and muscarinic receptors during differentiation of P19 carcinoma embryonic cells, as an in vitro model of early neurogenesis. We have detected expression and activity alpha(2)-alpha(7), beta(2), beta(4) nAChR and M1-M5 mAChR subtypes during neuronal differentiation. Nicotinic alpha(3) and beta(2) mRNA transcription was induced by addition of retinoic acid to P19 cells. Gene expression Of alpha(2), alpha(4)-alpha(7), beta(4) nAChR subunits decreased during initial differentiation and increased again when P19 cells underwent final maturation. Receptor response in terms of nicotinic agonist-evoked Ca2+, flux was observed in embryonic and neuronal-differentiated cells. Muscarinic receptor response, merely present in undifferentiated P19 cells, increased during neuronal differentiation. The nAChR-induced elevation of intracellular calcium ([Ca2+](i)) response in undifferentiated cells was due to Ca2+ influx. In differentiated P19 neurons the nAChR-induced [Ca2+](i) response was reduced following pretreatment with ryanodine, while the mAChR-induced response was unaffected indicating the contribution of Ca2+ release from ryanodine-sensitive stores to nAChR- but not mAChR-mediated Ca2+ responses. The presence of functional nAChRs in embryonic cells suggests that these receptors are involved in triggering Ca2+ waves during initial neuronal differentiation. (C) 2007 Elsevier Ltd. All rights reserved.

Transdural motor cortex stimulation reverses neuropathic pain in rats: A profile of neuronal activation

Motor cortex stimulation (MCS) has been used to treat patients with neuropathic pain resistant to other therapeutic approaches; however, the mechanisms of pain control by MCS are still not clearly understood. We have demonstrated that MCS increases the nociceptive threshold of naive conscious rats, with opioid participation. In the present study, the effect of transdural MCS on neuropathic pain in rats subjected to chronic constriction injury of the sciatic nerve was investigated. In addition, the pattern of neuronal activation, evaluated by Fos and Zif268 immunolabel, was performed in the spinal cord and brain sites associated with the modulation of persistent pain. MCS reversed the mechanical hyperalgesia and allodynia induced by peripheral neuropathy. After stimulation, Fos immunoreactivity (Fos-IR) decreased in the dorsal horn of the spinal cord and in the ventral posterior lateral and medial nuclei of the thalamus, when compared to animals with neuropathic pain. Furthermore, the MCS increased the Fos-IR in the periaqueductal gray, the anterior cingulate cortex and the central and basolateral amygdaloid nuclei. Zif268 results were similar to those obtained for Fos, although no changes were observed for Zif268 in the anterior cingulate cortex and the central amygdaloid nucleus after MCS. The present findings suggest that MCS reverts neuropathic pain phenomena in rats, mimicking the effect observed in humans, through activation of the limbic and descending pain inhibitory systems. Further investigation of the mechanisms involved in this effect may contribute to the improvement of the clinical treatment of persistent pain. (c) 2010 European Federation of International Association for the Study of Pain Chapters. Published by Elsevier Ltd. All rights reserved.

Environmental modulation of ethanol-induced locomotor activity: Correlation with neuronal activity in distinct brain regions of adolescent and adult Swiss mice

Drug abuse is a concerning health problem in adults and has been recognized as a major problem in adolescents. induction of immediate-early genes (IEG), such as c-Fos or Egr-1, is used to identify brain areas that become activated in response to various stimuli, including addictive drugs. It is known that the environment can alter the response to drugs of abuse. Accordingly, environmental cues may trigger drug-seeking behavior when the drug is repeatedly administered in a given environment. The goal of this study was first to examine for age differences in context-dependent sensitization and then evaluate IEG expression in different brain regions. For this, groups of mice received i.p. ethanol (2.0 g/kg) or saline in the test apparatus, while other groups received the solutions in the home cage, for 15 days. One week after this treatment phase, mice were challenged with ethanol injection. Acutely, ethanol increased both locomotor activity and IEG expression in different brain regions, indistinctly, in adolescent and adult mice. However, adults exhibited a typical context-dependent behavioral sensitization following repeated ethanol treatment, while adolescent mice presented gradually smaller locomotion across treatment, when ethanol was administered in a paired regimen with environment. Conversely, ethanol-treated adolescents expressed context-independent behavioral sensitization. Overall, repeated ethanol administration desensitized IEG expression in both adolescent and adult mice, but this effect was greatest in the nucleus accumbens and prefrontal cortex of adolescents treated in the context-dependent paradigm. These results suggest developmental differences in the sensitivity to the conditioned and unconditioned locomotor effects of ethanol. (C) 2008 Elsevier B.V. All rights reserved.

A multi-GPU algorithm for large-scale neuronal networks

Large-scale simulations of parts of the brain using detailed neuronal models to improve our understanding of brain functions are becoming a reality with the usage of supercomputers and large clusters. However, the high acquisition and maintenance cost of these computers, including the physical space, air conditioning, and electrical power, limits the number of simulations of this kind that scientists can perform. Modern commodity graphical cards, based on the CUDA platform, contain graphical processing units (GPUs) composed of hundreds of processors that can simultaneously execute thousands of threads and thus constitute a low-cost solution for many high-performance computing applications. In this work, we present a CUDA algorithm that enables the execution, on multiple GPUs, of simulations of large-scale networks composed of biologically realistic Hodgkin-Huxley neurons. The algorithm represents each neuron as a CUDA thread, which solves the set of coupled differential equations that model each neuron. Communication among neurons located in different GPUs is coordinated by the CPU. We obtained speedups of 40 for the simulation of 200k neurons that received random external input and speedups of 9 for a network with 200k neurons and 20M neuronal connections, in a single computer with two graphic boards with two GPUs each, when compared with a modern quad-core CPU. Copyright (C) 2010 John Wiley & Sons, Ltd.

Alpha7 Nicotinic Acetylcholine Receptor Expression and Activity During Neuronal Differentiation of PC12 Pheochromocytoma Cells

Nicotinic acetylcholine receptors (nAChR) exert pivotal roles in synaptic transmission, neuroprotection and differentiation. Particularly, homomeric alpha 7 receptors participate in neurite outgrowth, presynaptic control of neurotransmitter release and Ca(2+) influx. However, the study of recombinant alpha 7 nAChRs in transfected cell lines is difficult due to low expression of functional receptor channels. We show that PC12 pheochromocytoma cells induced to differentiation into neurons are an adequate model for studying differential nAChR gene expression and receptor activity. Whole-cell current recording indicated that receptor responses increased during the course of differentiation. Transcription of mRNAs coding for alpha 3, alpha 5, alpha 7, beta 2 and beta 4 subunits was present during the course of differentiation, while mRNAs coding for alpha 2, alpha 4 and beta 3 subunits were not expressed in PC12 cells. alpha 7 subunit expression was highest following 1 day of induction to differentiation. Activity of alpha 7 nAChRs, however, was most elevated on day 2 as revealed by inhibition experiments in the presence of 10 nM methyllycaconitine, rapid current decay and receptor responsiveness to the alpha 7 agonist choline. Increased alpha 7 receptor activity was noted when PC12 were induced to differentiation in the presence of choline, confirming that chronic agonist treatment augments nAChR activity. In summary, PC12 cells are an adequate model to study the role and pharmacological properties of this receptor during neuronal differentiation.

Uma Comparação Fenomenográfica das Pesquisas Científicas sobre o Ensino de Sociologia na Rede Escolar Sueca e Pública Brasileira

O objetivo deste artigo é realizar um estudo sobre as perspectivas teórica-metodológicas sobre o ensino de licenciatura em Ciências Sociais, no Brasil e na Suécia. Priorizando uma análise dos temas, das teórias e das conclusões das teses escritas em inglês, sueco e em português sobre a temática, quero aprensentar uma revisão bibliográfica sobre o tema, produzida no período entre 2006-2012

A rede de negócios do turismo: um estudo sobre suas características e implicações estratégicas

A atividade turística é representativa para o país em termos econômicos e sociais. A rede de negócios do turismo é formada por um complexo conjunto de elementos, que incluem os relacionamentos entre seus integrantes como parte fundamental no seu desenvolvimento. O presente trabalho busca analisar os relacionamentos existentes na rede de negócios do turismo, a fim de averiguar a qualidade dos negócios nela gerados. Para tanto, realizou-se um estudo exploratório junto às entidades representativas e empresas privadas do setor. A amostra foi selecionada de forma não probabilística, por escolha justificada, tendo sido realizadas 15 entrevistas pessoais com associações de classe, operadoras turísticas, hotéis, agências de viagem, transportadoras aéreas e organizadoras de eventos. Os resultados indicam que essa rede se caracteriza por apresentar alguns negócios comuns nos quais o nível de cooperação e integração entre seus participantes é baixo e ocasional, visto que suas estratégias privilegiam os interesses individuais e de curto prazo. A conseqüência desse processo acaba por prejudicar o desempenho e a expansão da rede de negócios do turismo em sua totalidade.

Twitter: microblog e rede social

Trata-se de uma pesquisa exploratória sobre o Twitter, um tipo rede social na Internet em formato de microblog. A questão central foi compreender a popularização do serviço, sobretudo no Brasil, e como este pode ser utilizado como ferramenta de comunicação pessoal ou, mesmo, corporativa. Este estudo preliminar foi desenvolvido por meio de pesquisa documental sobre redes sociais na Internet e pesquisa exploratória, com base em artigos publicados sobre o Twitter. A principal constatação é que a utilização das redes sociais como o Twitter para difusão de informações, sejam pessoais, sejam corporativas, utilizando-se de perfis reais e institucionais em sua divulgação, gera maior credibilidade das ações desenvolvidas, bem como estas são mais rápidas e podem ser acessadas via browser ou aplicativos que rodam em outros gadgets, como celulares ou smartphones.

A influência do relacionamento em rede na internacionalização das empresas do pólo brasileiro de cosméticos de Diadema - SP

Dissertação apresentada ao Programa de Mestrado em Administração da Universidade Municipal de São Caetano do Sul - USCS

Relacionamentos interorganizacionas em rede de cooperação: um estudo no setor farmacêutico varejista do estado de São Paulo

SILVA, Rosangêla Sarmento. Relacionamento interorganizacionais em rede de cooperação: um estudo no setor farmacêutico varejista do estado de São Paulo. 2012. 172f. Dissertação (Mestrado em Administração)-Universidade Municipal de São Caetano dos Sul, São Caetano do Sul, 2012.

A rede de empresas voltada à viabilização de ações estratégicas de sustentabilidade em grandes bancos privados atuantes no Brasil

TEIXEIRA, Carlos Alberto Chagas. A rede de empresas voltada à viabilização de ações estratégicas de sustentabilidade em grandes bancos privados atuantes no Brasil. 2013. 159f. Dissertação (Mestrado em Administração)-Universidade Municipal de São Caetano do Sul, São Caetano do Sul, 2013.

Lápides Virtuais: análise das narrativas sobre a morte na rede social Orkut

Dissertação apresentada ao Programa de Pós-graduação em Comunicação da Universidade Municipal de São Caetano do Sul

Coopetição entre empresas atuantes na rede de negócio de terminal líquido na cidade de Santos

Dissertação de mestrado apresentada como exigência parcial para obtenção do título de Mestre em Administração no Programa de Pós-graduação em Administração da Universidade Municipal de São Caetano do Sul.

Avaliação dos serviços da rede Accor Hospitality na região do Grande ABC Paulista

Dissertação de Mestrado apresentada ao Programa de Pós-Graduação em Administração da Universidade Municipal de São Caetano do Sul - USCS