GABA and glutamate transporters: new events and function in the vertebrate retina

The neural retina is a highly complex tissue composed of excitatory and inhibitory neurons and glial cells. Glutamate, the main excitatory neurotransmitter, mediates information transfer from photoreceptors, bipolar cells, and ganglion cells, whereas interneurons, mainly amacrine and horizontal cells, use γ-aminobutyric acid (GABA), the main inhibitory neurotransmitter. In this review we place an emphasis on glutamate and GABA transporters as highly regulated molecules that play fundamental roles in neurotransmitter clearance, neurotransmitter release, and oxidative stress. We pharmacologically characterized glutamate transporters in chicken retina cells and identified two glutamate transporters: one Na+-dependent transporter and one Na+-independent transporter. The Na+-dependent uptake system presented characteristics related to the high-affinity xAG- system (EAAT1), and the Na+-independent uptake system presented characteristics related to the xCG- system, which highly contributes to glutamate transport in the retina. Glutamate shares the xCG- system with another amino acid, L-cysteine, suggesting the possible involvement of glutathione. Both transporter proteins are present mainly in Müller glial cells. GABA transporters (GATs) mediate high-affinity GABA uptake from the extracellular space and terminate the synaptic action of GABA in the central nervous system. GABA transporters can be modulated by molecules that act on specific sites to promote transporter phosphorylation and dephosphorylation. In addition to a role in the clearance of GABA, GATs may also release GABA through a reverse transport mechanism. In the chicken retina, a GAT-1 blocker, but not GAT2/3 blocker, was shown to inhibit GABA uptake, suggesting that GABA release from retina cells is mainly mediated by a GAT-1-like transporter.

Estudo comparativo da veiculação do diclofenaco sódico pela fonoforese de alta e baixa frequência em ratos / Comparative study of sodic diclofenaco veiculation by fonoforesis using high and low frequency in rats

Objetivo: estudar a aplicação do ultrassom terapêutico com alta frequência-3MH em estudo comparativo com aplicação do ultrassom terapêutico de baixa frequência-1MHz, na indução do aumento na absorção transcutânea do diclofenaco de sódio pela pele de ratos. Método: estudo experimental utilizando 15 ratos machos, adultos, da linhagem Wistar, com peso entre 250 a 350 gramas, distribuídos em três grupos: Alta, Baixa Frequência e Controle de 5 ratos cada. Foram coletadas 4 amostras de sangue de cada animal, nos tempos de 0? antes da aplicação do ultrassom, 30?, 60? e 90? minutos após a realização da técnica específica para cada grupo. Na leitura das amostras, foi utilizado o equipamento de Cromatografia Líquida de Alta Eficiência-CLAE. Resultado: a análise foi obtida através do método não paramétrico, ANOVA de Kruskal-Wallis, não comprovando diferença estatisticamente significante entre os grupos analisados no que diz respeito a maior absorção do fármaco. Conclusão: os resultados obtidos sugerem novos estudos, que busquem aperfeiçoar o método aplicado e possa agregar maiores conhecimentos ao assunto pesquisado o que possibilitará resultados cada vez mais precisos.

Objective: to study the application of therapeutic ultrasound with high frequency-3MH in a comparative study with application of therapeutic ultrasound, low-frequency 1MHz-induced increase in transcutaneous absorption of diclofenac sodium by the skin of mice. Method: an experimental study using 15 male rats, adult male rats, weighing 250 to 350 grams were divided into three groups: High, Low Frequency Control and 5 mice each. We collected 4 blood samples from each animal at 0 'prior to the application of ultrasound, 30', 60 'and 90' minutes after the completion of specific techniques for each group. In reading the samples, we used the equipment Chromatography High Performance Liquid-HPLC. Result: the analysis was performed using the method nonparametricANOVA Kruskal-Wallis test does not confirm a statistically significant difference between the groups with regard to the greater absorption of the drug. Conclusion: the results suggest further studies that seek to improve the methodology used, and may add more knowledge to the subject researched the results will enable more precise.

Atividade anti-inflamatória do óleo-resina da Copaífera reticulata em modelo inflamatório de edema de pata / Anti-inflammatory activity of the oil-resin Copaífera reticulata of model inflamatory paw edema

Objetivo: avaliar a ação do óleo-resina de copaíba da espécie copaifera reticulata como anti-inflamatório em modelos experimentais de reação inflamatória aguda. Método: o estudo experimental foi realizado no Laboratório de Imunofarmacologia da Fundação Instituto Oswaldo Cruz ? FIOCRUZ/RJ, foram utilizados 30 (trinta) camundongos da linhagem Swiss Webster (SW). O óleo-resina de copaíba utilizada foi extraído de árvore da espécie Copaífera reticulata. O modelo de inflamação aguda induzida por carragenina foi utilizado para avaliar o efeito anti-inflamatório das concentrações, foi utilizado o teste estatístico de Kruskal-Wallis para comparar os valores medianos conforme os grupos com nível de significância alfa = 0,05. Resultados: no grupo C500 ocorreu significativa redução do volume no instante T3; somente os grupos Indo e C10 apresentaram significativa redução do volume em T6. Não houve diferença estatisticamente significante no Índice de Inibição do Edema nos grupos (Indo, C10, C100 e C500) nos intantes T1, T3 e T6. Conclusão: a atividade anti-inflamatória do óleo-resina foi confirmada pelo modelo do edema de pata induzido por carragenina através da redução do volume deslocado.

Objective: To evaluate the action of the oil-resin of Copaiba Copaifera reticulata as anti-inflammatory effect in experimental models of acute inflammatory reaction. Method: A total of 30 (thirty) mice of Swiss strain Webster (SW). The oil-resin of Copaiba used was extracted from tree species Copaifera reticulata. The model of acute inflammation induced by carrageenan was used to evaluate the anti-inflammatory effect of the extracts, we used the statistical test of Kruskal-Wallis test to compare the median values for the different groups with a significance level alpha = 0.05. Results: The group C500 was a significant reduction in the volume at time T3, only the Indus and C10 groups showed significant reduction in volume at T6. There was no statistically significant difference in the Index of Inhibition of edema in groups (Indo, C10, C100 and C500), in the instant, T1, T3 and T6. Conclusion: The anti-inflammatory activity of oil-resin was confirmed by the model of paw edema induced by carrageenan by reducing the volume displaced.

Primary endemic Cryptococcosis gattii by molecular type VGII in the state of Pará, Brazil

In order to study the infectious agents causing human disseminated cryptococcosis in the state of Pará, North Brazil, 56 isolates of Cryptococcusspp. (54 isolated from cerebral spinal fluid and two from blood cultures) from 43 cases diagnosed between 2003-2007 were analysed. The species were determined through morphological and physiological tests and genotypes were determined by URA5-RFLP and PCR-fingerprinting (wild-type phage M13). The following species and genotypes were identified: Cryptococcus neoformans VNI (28/56, 50 percent), Cryptococcus gattii VGII (25/56, 44.64 percent) and C. gattii VGI (3/56, 5.26 percent). The genotype VNI occurred in 12 out of 14 HIV-positive adults, whereas the genotype VGII occurred in 11 out of 21 HIV-negative adults (p < 0.02, OR = 6.6 IC95 percent 0.98-56.0). All patients less than 12 years old were HIV negative and six cases were caused by the VGII genotype, one by the VGI and one by VNI. Therefore, endemic primary mycosis in HIV-negative individuals, including an unexpectedly high number of children, caused by the VGII genotype deserves further study and suggests the need for surveillance on cryptococcal infection in the state of Pará, Eastern Amazon.

Methylmercury neurotoxicity & antioxidant defenses.

Neurotoxicity induced by methylmercury (MeHg) increases the formation of reactive radicals and accelerates free radical reactions. This review summarizes recent findings in the MeHg-induced formation of free radicals and the role of oxidative stress in its neurotoxicity. Oxidative stress on CNS can produce damage by several interacting mechanisms, including mitochondrial damage with increase in intracellular free Ca(2+), activation and inhibition of enzymes, release of excitatory amino acids, metallothioneins expression, and microtubule disassembly. The nature of antioxidants is discussed and it is suggested that antioxidant enzymes and others antioxidants molecules may protect the central nervous system against neurotoxicity caused by MeHg.

Exposição humana ao mercúrio na região oeste do Estado o Pará / Human Exposure to mercury in the west region of state of Pará

Objetivo: realizar um levantamento da literatura existente sobre os níveis de exposição mercurial das populações da região oeste do Estado do Pará. Método: revisão bibliográfica pertinente ao objetivo. Conclusão: os níveis do mercúrio detectados por diferentes trabalhos em populações expostas da bacia do Rio Tapajós foram elevados em certas comunidades (São Luís do Tapajós, Barreiras e Rainha), no entanto, apresentando uma diminuição gradual com o passar dos anos. Esses mesmos dados revelam uma exposição ambiental ao mercúrio de comunidades vizinhas com valores significativos. A exposição mercurial pode ser perigosa, por gerar níveis de intoxicação que estão acima do limite determinado pela Organização Mundial de Saúde, podendo desencadear neurotoxicidade, perda do controle motor entre outros problemas de saúde

Viabilidade celular da mucosa do intestino delgado de ratos, após correçäo de choque hipovolêmico com soluçäo de NaCl 7,5 por cento / Celular viability of rat small bowel mucosa, after hypovolemic shock correction with NaCl 7,5 percent solution

OBJETIVO: Estudar o efeito da correçäo volêmica com diferentes tipos de soluçäo, na mucosa do intestino delgado de ratos. MÉTODOS: Foram utilizados 120 ratos Wistar (Rattus norvegicus albinus), machos, adultos, com peso individual entre 310 e 410g, oriundos do Instituto Evandro Chagas de Belém do Pará, submetidos a período de adaptaçäo por 15 dias, recebendo água e raçäo ad libitum, durante todo o experimento. Os animais foram distribuídos em: Grupo Padräo (P), Grupo Choque (C), Grupo Soluçäo Fisiológica (SF) e Grupo Soluçäo Hipertônica (SH), com 30 animais cada. Estes foram divididos em subgrupos com 10 animais cada, de acordo com o dia de pós-operatório (DPO) previsto para a eutanásia dos animais, (1º, 3º ou 7º DPO), sendo após esta, colhido material para realizaçäo de teste de absorvância pelo MTT em todos os animais. RESULTADOS: O grupo SF apresentou menores índices de viabilidade celular comparado aos grupos SH e C (p<0.05). CONCLUSÄO: A correçäo volêmica com soluçäo de cloreto de sódio a 7.5 por cento levou a manutençäo de maior quantidade de células viáveis, no intestino delgado em ratos no 7º dia do experimento.

VII Fórum Nacional da SBACV: patologia de carótida: inocaçöes no diagnóstico e tratamento / Pathology of the carotid artery: diagnostic and treatment innovations

The Brazilian National Forum on Carotid Surgery gathered the consensus of 15 Regional Chapters of the Braziliam Society of Angiology an Vascular Surgery.Established diagnostic method and newly developed tecchiques were discusses.Concerning the method of anesthesia, there was a concensus that the surgical skills, rather tan the type of anesthesia, are the main factors for good or bad results.Local anesthesis does not avoid complications caused by inadequte technique.There was a concensus that utilization of a temporary shunt in select cases may lower the incidence of post-operative neurologic deficits, wich not surpas 3 porcents.Angioplasty and carotid stenting were considered experimental procedures and with no approval of the medical community so far, except when performed under research protocols, submitted to boards of ethics and with informed consent.Finally, it was emphasized that the carotid surgery is to be perfomed in regional centers to which patients should be referred in order to archieve the best results.

Neurotransmitter release in aggregate cultures of chick embryo retina cells

The study of neurotransmitter release using aggregate cell cultures has been limited by the fact that cell aggregates are obtained only when cells are maintained in suspension with rotatory agitation. In this report we describe a simple and easy method that uses aggregate cell cultures to study the release of neurotransmitters. The results demonstrate that this relatively simple technique can be of great value to address the problem of neurotransmitter release and study the mechanisms of action of natural and synthetic compounds on the differentiation of functional synapses in the CNS.