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Orientadores: Susanne Rath, Jarbas Jose Rodrigues Rohwedder / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-09T10:51:51Z (GMT). No. of bitstreams: 1 Winter_Eduardo_D.pdf: 3366512 bytes, checksum: 6c8baea3dd6502c19761ad449683bb95 (MD5) Previous issue date: 2007 / Resumo: Muitas doenças neurodegenerativas são associadas com disfunções de neurotransmissores, em particular catecolaminas, no cérebro. Numerosas pesquisas têm indicado que íons metálicos podem induzir estresse oxidativo - dependente da neurodegeneração de dopamina e são responsáveis pelo aparecimento de doenças neurodegenerativas. Em estudos prévios foi verificado que alguns carboxilatos diminuem a velocidade de oxidação de catecolaminas e inibem a passivação de eletrodos sólidos durante a análise voltamétrica destes compostos fenólicos. Este trabalho teve por objetivo estudar a influência de carboxilatos (EDTA, NTA, EGTA, DTPA, acetato, citrato e oxalato) e íons metálicos (Ce(IV), Fe(III) e Hg(II)) durante a oxidação de neurotransmissores (dopamina, serotonina, epinefrina, norepinefrina e L-dopa) no intuito de estabelecer mecanismos de reações que possam contribuir no esclarecimento do papel destes compostos no processo de degeneração dos neurotransmissores, assim como compreender como os carboxilatos inibem o envenenamento do eletrodo durante a varredura de potencial. Para eses propósitos foram empregadas as técnicas de espectrofotometria, voltametria e espectroeletroquímica. A cela espectroeletroquímica de camada delgada desenvolvida incorporou um sistema de três eletrodos, sendo o eletrodo de trabalho uma minigrade de Pt. O sistema foi caracterizado usando o-tolidina e K4[Fe(CN)6]/ K3[Fe(CN)6] e permitiu o monitoramento das reações in situ. Os resultados obtidos mostraram que os carboxilatos desprotonados interagem com os produtos intermediários formados durante a oxidação das catecolaminas por meio de ligações de hidrogênio, sendo estas interações dependentes do pH do meio, estruturas do carboxilato e do próprio neurotransmissor. Foi proposto um mecanismo eletroquímico para a oxidação de aminas biogênicas na presença de carboxilatos no eletrodo de platina. A estabilização dos produtos intermediários formados inibe a formação de compostos poliméricos que são responsáveis pelo envenenamento do eletrodo. Do mesmo modo, os carboxilatos retardam ou inibem a oxidação química de algumas aminas biogênicas por íons metálicos / Abstract: Several neurological disorders are associated with improper catechoalmine regulation in the brain. Numerous researches have indicated that metallic ions can induce oxidative stress-dependent neurodegeneration of dopamine, and are responsible for the induction of neurodegenerative diseases. In previous work was verified that some carboxylates diminishes the oxidation rate of catecholamines and inhibit the well known solid state electrode passivation during voltammetric analysis of these phenolic compounds. The aim of this work was to study the influence of carboxylates (EDTA, NTA, EGTA, DTPA, acetate, oxalate and citrate) and metallic ions (Ce(IV), Fe(III) and Hg(II)) during the oxidation of neurotransmitters (dopamine, serotonin, epinephrine, norepinephrine and L-dopa) in order to establish putative reaction mechanism which could contribute to understand the role of these compounds in neurodegenerative processes, as well as comprehend how the carboxylates inhibit the electrode fouling during potential scan. For these purposes, the studies were carried out using spectrophotometric, voltammetric and spectroelectrochemical techniques. The spectroelectrochemical thin layer cell developed incorporated a three electrode system, using a Pt- minigrade as working electrode. The system was characterized employing o-tolidine and K4[Fe(CN)6]/ K3[Fe(CN)6] and allowed monitoring the electrode reactions in situ. The results obtained showed that the deprotonated carboxylates interacts with the intermediates formed at the electrochemical oxidation of catecholamines by hydrogen bonds. These interactions are dependent on the pH of the medium, as well as on the chemical structures of the carboxylates and neurotransmitters itself. An electrochemical mechanism for the oxidation of biogenic amines in the presence of carboxylates at the platinum electrode is proposed. The stabilization of the intermediates formed inhibits the formation of polymeric compounds that are responsible for the electrode fouling. In the same manner, the carbolxylates retards or inhibit the chemical oxidation of some biogenic amines by metallic ions by the same reaction pathway / Doutorado / Quimica Analitica / Doutor em Ciências

A Doença de Parkinson, uma condição neurodegenerativa e progressiva, está relacionada à morte de neurônios localizados na Substância Negra compacta, um dos componentes dos Núcleos da Base. Quando há a morte de neurônios dopaminérgicos nigrais, esta via modulatória é perdida, levando ao desequilíbrio entre as vias direta e indireta, esta última tendo sua atividade aumentada em detrimento da outra. O estriado tem um papel importante no recebimento e filtração de sinais motores corticais e talâmicos e suas maiores populações neuronais são GABAérgicas, demonstrando a importância do neurotransmissor GABA nesta modulação. O estriado recebe projeções dopaminérgicas vindas da Substância Negra compacta e, na falta desta aferentação, surgem os sintomas e sinais da Doença de Parkinson. Nosso objetivo é caracterizar a liberação de GABA nesta estrutura, avaliando os efeitos de outros transmissores e também o papel de alguns sinalizadores intracelulares neste processo. Para isto, empregamos o método de superfusão e liberação de GABA radiomarcado, previamente carregado, em tecido picado in vitro. A lesão nigral é produzida por cirurgia estereotáxica e microinjeção de 6-OHDA no feixe medial prosencefálico (mfb). Diversas drogas foram utilizadas para avaliarmos diferentes passos na liberação do transmissor. Concluímos que a liberação é fortemente dependente de cálcio e segue o modelo de exocitose vesicular, além de a subpopulação neuronal GABAérgica estrital estudada sofrer pouca influência de aferências glutamatérgicas e colinérgicas. No entanto, drogas dopaminérgicas regulam complexamente a liberação de GABA no estriado e ela também é bastante dependente de calmodulina. Conjecturamos se algumas drogas antipsicóticas que agem sobre calmodulina devem seu efeito terapêutico, ou parte dele, a esta ação e se, no modelo de DP de lesão unilateral por 6-OHDA, há comunicação entre os hemisférios lesado e não lesado após o estabelecimento da lesão e processo de rearranjo neuronal / Parkinsons disease, a progressive and neurodegenerative condition, is related to the death of neurons located in Substantia Nigra compacta, a component of Basal Ganglia. When nigral dopaminergic neurons die, this modulatory pathway is lost leading to imbalance between direct and indirect pathways, the latter having its activity increased over the former. Striatum has an essential role in receiving and filtering motor signals from cortex and thalamus and its major neuronal populations are composed by GABAergic neurons, showing how important is GABA in this modulation. Striatum receives dopaminergic projections from Substantia Nigra compacta and in its absence the typical signals and symptoms of the disease arise. We aimed to characterize GABA relase at this structure, assessing the effect of other transmitters as well the role of some intracellular signaling molecules in this process. For that, we employed the superfusion method and release of preloaded radiolabeled GABA from chopped striatal tissue. Nigral injury was produced by stereotaxic surgery and 6-OHDA microinjection at medial forebrain bundle (mfb). Several drugs were used to evaluate different steps in transmitter release. We concluded that the release is strongly calcium-dependent and follows vesicular exocytosis model; in addition the striatal GABAergic subpopulation of neurons studied here undergo little influence of glutamatergic and cholinergic afferents. However, dopaminergic drugs complexly regulate striatal GABA release and it also shows high involvement of calmodulin. We wonder if some antipsychotic drugs that act over calmodulin owe their therapeutical effects, or at least part of it, to this activity and if in 6-OHDA unilateral lesion parkinsonism model there is communication between injuried and healthy hemispheres after the establishment of the injury and neuronal rearrangement process

In this study, the presence and possible function of endocannabinoid ligands in the planarian is investigated. The endocannabinoids ananadamide (AEA) and 2-arachidonoylglycerol (2-AG) and entourage NAE compounds palmitoylethanolamide (PEA), stearoylethanolamide (SEA) and oleoylethanolamide (OEA) were found in Dugesia dorotocephala. Changes in SEA, PEA, and AEA levels were observed over the initial twelve hours of active regeneration. Exogenously applied AEA, 2-AG and their catabolic inhibition effected biphasic changes in locomotor velocity, analogous to those observed in murines. The genome of a close relative, Schmidtea mediterranea, courtesy of the University of Utah S. med genome database, was explored for cannabinoid receptors, none were found. A putative fatty acid amide hydrolase (FAAH) homolog was found in Schmidtea mediterranea.

A central question in neuroscience is to identify the roles of genes in behavior. A deeper understanding of genetic influences on behavior would provide insight into the relative impact of innate vs. environmental influences on behavior, as well as improve treatments for neurological diseases. To elucidate the role of genes in behavior, we must not only identify specific genes involved, but also determine the cell types in which they act and the mechanisms by which they exert their influence. In Chapter 2 of this thesis, I found that circadian genes comprising the circadian clock were not necessary in “master clock neurons”, or Pdf+ neurons, for circadian locomotor rhythms. I also identified a small subset of neurons in which disruption of these circadian genes completely abolishes Drosophila circadian behavior. In Chapter 3, I describe the role of a glial gene, ebony, in the regulation of Drosophila courtship and sleep behavior. In addition to identifying the cell types in which ebony acts to regulate these behaviors, I also provide insight into the underlying mechanism of neurotransmitter modulation. The results in this chapter highlight the consideration of non-neuronal cells in the brain when examining the roles of genes in behavior. Together, the results in Chapter 2 and 3 further our understanding of how genes in small populations of cells influence a myriad of conserved Drosophila behaviors.

Smoking is one of the leading causes of death in the world. About 80% of smokers start smoking before the age of 18. In the Appalachian area and the South in the United States, smoking percentages among adults and adolescents are higher than in other regions. Female smoking shows a variety of different trends from male smoking, and smoking brings particular health problems related to production to female smokers. These findings highlighted the importance of studying female teenage smokers in southwest Virginia. The initial project aimed to identify risk factors that might prevent smoking in an early stage. Dr. Helen Crawford led the Cognitive Neuroscience Lab at Virginia Tech in discovering the psychophysiological vulnerabilities of female teenage smokers. Toward this end, event-related potential (ERP), personality, and behavioral data were collected in teenage female smokers and non-smokers. These data were analyzed to examine possible psychophysiological vulnerabilities in female teenage smokers such as deficits in brain and cognitive function, personality traits, and environment influences. The purpose of this dissertation is to further analyze these data to elaborate and clarify the relationships among these vulnerabilities toward understanding teenage smoking behavior. Participants were 49 teenage girls (smokers and non-smokers) with age from 14 to 18. The measures included sensory gating, platelet MAO-B activity, attention, memory, temperament, schizotypal personality, recognition of facial expressions, taste and smell. The initial set of analyses compared smokers and non-smokers, including those classified as high and low dependent, on all dependent measures. The results suggested some psychophysiological vulnerabilities in female teenage smokers, which have been used as support for the self-medication and the orbito-frontal dysfunction models of why teenagers smoke (Crawford et al., 2004). Further examination of these factors may help teenagers to reduce the smoking dependency and possibly improve cognitive function. Specifically, this dissertation focused on the role of the variable of monoamine oxidase-B (MAO-B) in the correlations among sensory gating, MAO and other cognitive and personality measures. All smokers were divided into high and low MAO groups first. Comparison analyses were conducted between them. The high MAO group showed better sensory gating function than the low MAO group. Correlation analyses were conducted among all of the measures. The significant linear relationships between MAO and sensory gating, MAO and CO level and MAO and temperament were demonstrated. MAO activity positively correlated with the sensory gating function and negatively correlated with CO level and temperament characteristics. Finally, to explore the mechanisms of the relationship between MAO and sensory gating, the neurotransmitter systems related to MAO and sensory gating were discussed. / Ph. D.

The goal of this experiment was to examine the pattern of ACh release in mPFC and HPC during performance in trace and delay appetitive conditioning.

Resumo A nicotina é um alcalóide encontrado em cigarros de tabaco sendo um dos maiores responsáveis pelo vício e por problemas associados ao tabagismo. Com relação ao vício, que é um fenômeno comportamental complexo, ressaltamos a ação da nicotina como um potente agente viciante que altera não só mecanismos celulares como também comportamentais e de aprendizagem. O trabalho para a reversão do vício a drogas como a nicotina é bastante difícil de modo que intervenções alternativas, como o exercício físico, são práticas que têm estado cada vez mais em evidência. Após tratarmos cronicamente ou não ratos com nicotina durante 60 dias e submetê-los ou não a atividade física espontânea por 7 semanas, verificamos que nem o tratamento crônico com a droga e nem a atividade física alteraram parâmetros como o peso e a pressão arterial média dos ratos bem como a marcação para o RNAm da enzima tirosina hidroxilase na Área Tegmental Ventral e da glutaminase no Córtex Pré-Frontal. Porém, verificamos alterações na frequência cardíaca e na ansiedade dos ratos, além do RNAm da glutaminase e do fator neurotrófico derivado do cérebro em áreas hipocampais, sugerindo que ambos o treinamento físico espontâneo e o tratamento crônico com nicotina podem alterar o comportamento, a ansiedade e a memória dos ratos utilizados. / Resumo A nicotina é um alcalóide encontrado em cigarros de tabaco sendo um dos maiores responsáveis pelo vício e por problemas associados ao tabagismo. Com relação ao vício, que é um fenômeno comportamental complexo, ressaltamos a ação da nicotina como um potente agente viciante que altera não só mecanismos celulares como também comportamentais e de aprendizagem. O trabalho para a reversão do vício a drogas como a nicotina é bastante difícil de modo que intervenções alternativas, como o exercício físico, são práticas que têm estado cada vez mais em evidência. Após tratarmos cronicamente ou não ratos com nicotina durante 60 dias e submetê-los ou não a atividade física espontânea por 7 semanas, verificamos que nem o tratamento crônico com a droga e nem a atividade física alteraram parâmetros como o peso e a pressão arterial média dos ratos bem como a marcação para o RNAm da enzima tirosina hidroxilase na Área Tegmental Ventral e da glutaminase no Córtex Pré-Frontal. Porém, verificamos alterações na frequência cardíaca e na ansiedade dos ratos, além do RNAm da glutaminase e do fator neurotrófico derivado do cérebro em áreas hipocampais, sugerindo que ambos o treinamento físico espontâneo e o tratamento crônico com nicotina podem alterar o comportamento, a ansiedade e a memória dos ratos utilizados.

published_or_final_version / Physiology / Doctoral / Doctor of Philosophy

Removal of the pineal gland from partially parathyroidectomized rats produces stereotyped violent seizures. Inasmuch as the neurotransmitter norepinephrine (NE) has been implicated in this experimental paradigm, the purpose of this study was to investigate the effect of specific alterations in catecholamine function on convulsions produced by pinealectomy (PinX). Additionally, the role of various pineal substances, sex differences and the caging paradigm in the convulsive response was studied. Male and female rats (grouped five per cage) were found to respond similarly to the convulsive stimulus of parathyroidectomy followed by PinX. Neither implants of melatonin nor ventricular injections of arginine vasotocin in isolated and grouped rats, respectively, produced consistent changes in convulsions from PinX. The method of caging the rats after PinX, however, dramatically influenced seizures. Isolated rats (one per cage) convulsed significantly later after PinX and did so less often than grouped (five per cage) controls. NE neurotransmission appears to play a strong role in influencing PinX-induced seizures. Augmenting NE function with desipramine suppressed seizures. Convulsions were enhanced by the (beta)-receptor antagonist timolol, while neonatal injections of the catecholamine neurotoxin 6-OHDA potentiated seizures so markedly that many rats died from just one convulsion. NE levels were significantly reduced in the telencephalons and increased in the brain stems of sham-pinealectomized rats which had also received neonatal 6-OHDA; telencephalic levels of DA were elevated by 6-OHDA. Both the proconvulsant effects of 6-OHDA and the alterations it produced in central catecholamine levels were prevented, for the most part, by pretreatment with DMI. Altering both NE and DA function with L-dihydroxyphenylalanine, (alpha)-methyl-p-tyrosine, FLA-63 or reserpine did not significantly affect PinX-induced seizures in isolated rats. NE appears to play a strong role in modulating PinX-induced seizures; however, a deficit in NE function per se does not seem to be the fundamental cause of the seizures since sham-pinealectomized rats having lowered NE and/or DA function did not convulse.