ADHD pharmacotherapy uses methylphenidate (MPH), D-amphetamine (D- amph), two psychostimulants targeting dopamine transporters, or atomoxetine (ATX), specifically targeting norepinephrine transporters. We have assessed the pharmacological mechanisms of these three drugs on the in vitro efflux of neurotransmitters in rat prefrontal cortex (PFC) and striatal slices as well as on the in vivo electrical activities of PFC pyramidal neurons, striatal medium spiny neurons, ventral tegmental area dopamine neurons or dorsal raphe nucleus serotonin neurons, using single cell extracellular electrophysiological recording techniques. We have also tested whether chronic methylphenidate treatment, during either adolescence or adulthood, could have long-lasting consequences on body growth, depression and neuronal functions. Release experiments showed that all ADHD drugs induce dose-dependent dopamine efflux in both the PFC and striatum, with different efficacies, while only D- amph induced cortical norepinephrine efflux. Atomoxetine induced an unexpected massive dopamine outflow in striatal regions, by mechanisms that depend on physiological parameters. Our electrophysiological studies indicate that all three drugs equally stimulate the excitability of PFC pyramidal neurons, in basal and NMDA-evoked conditions, when administered acutely (3 mg/kg). While the electrophysiological effects elicited by psychostimulants may be dependent on D1 receptor activation, those induced by atomoxetine relied on different mechanisms. In the ventral tegmental area (VTA), methylphenidate (2 mg/kg), but not atomoxetine, induced firing and burst activity reductions, through dopamine D2 autoreceptor activation. Reversal of such effects (eticlopride 0.2 mg/kg) revealed an excitatory effect of methylphenidate on midbrain dopamine neurons that appear to be dependent on glutamate pathways and the combination of D1 and alpha-1 receptors. Finally, acute intraperitoneal psychostimulant injections increased vertical locomotor activity as well as NMDA2B protein expression in the striatum. Some animals chronically treated with intraperitoneal administrations (methylphenidate 4 mg/kg/day or saline 1.2 ml/kg/day) showed decreased body weight gain. Voluntary oral methylphenidate intake induces desensitisation to subsequent intravenous methylphenidate challenges, without altering dopamine D2 receptor plasticity. Significant decreases in striatal NMDA2B protein expression were observed in animals chronically treated. After adolescent MPH treatment, midbrain dopaminergic neurons do not display either desensitisation or sensitisation to intravenous methylphenidate re-challenges. However, partial dopamine D2 receptor desensitisation was observed in midbrain dopamine neurons. Using behavioural experiments, cross-sensitisation between adolescent methylphenidate exposure and later-life D-amphetamine challenge was observed. Significant decreases in striatal NMDA2B protein expression were observed in animals chronically treated, while striatal medium spiny neurons showed decreased sensitivities to locally applied NMDA and dopamine. While caffeine is devoid of action on baseline spike generation and burst activity of dopamine neurons, nicotine induces either firing rate enhancement, firing rate reduction, or has no consequences. Adolescent methylphenidate treatment leads to decreased neuronal sensitivities to the combination of nicotine, MPH and eticlopride, compared to controls. Finally, nicotine partially prevented D-amphetamine-induced increase of rearing activities. Our results show that increases in the excitability of PFC neurons in basal conditions and via NMDA receptor activation may be involved in the therapeutic response to ADHD drugs. Long-term consequences were observed after psychostimulant exposure. Such novel findings strengthen the mixed hypothesis in ADHD, whereby both dopamine and glutamate neurotransmissions are dysregulated. Therefore, ADHD therapy may now focus on adequate balancing between glutamate and dopamine.

Os escorpiões são um dos grupos de animais mais antigos da Terra. Eles são artrópodes e pertecem a classe Arachinida e Ordem Scorpionida. A família Buthidae compreende as espécies responsáveis pelos acidentes graves em humanos, incluindo a espécie Tityus serrulatus, o maior responsável por esses acidentes no Brasil. A peçonha do T. serrulatus contém diversas neurotoxinas que agem especificamente em canais para sódio, potássio e cálcio da membrana plasmática de células excitáveis, causando massiva liberação de neurotransmissores.As toxinas escorpiônicas podem ser usadas como ferramentas nos estudos de estrutura e função desses canais iônicos sensíveis a voltagem e também no estudo de liberação e captação de neurotransmissores. As toxinas escôrpionicas específicas para canais para sódio sensíveis a voltagem são as principais responsáveis pelos efeitos do envenenamento por estes artrópodes e podem ser classificadas em duas classes: toxinas e . As -toxinas retardam a inativação desses canais induzindo assim um prolongamento na fase de repolarização do potencial de ação. As - toxinas alteram a dependência de voltagem de ativação dos canais para sódio para potenciais mais negativos provocando potenciais de ação espontâneos e repetitivos. As toxinas específicas para canais para potássio (KTx) são geralmente peptídeos pequenos e de caráter básico, formados por 23-43 aminoácidos estabilizados por 3-4 pontes dissulfeto. As KTx são classificadas em 4 subfamílias:, , , . Neste trabalho, uma nova neurotoxina do escorpião T. serrulatus foi isolada e caracterizada bioquímica e funcionalmente. A toxina foi testada em ampla variedade de canais incluindo 5 subtipos de canais para sódio (Nav1.4; Nav1.5; Nav1.6; Nav1.8 e DmNav1) e 12 diferentes tipos de canais para potássio (Kv1.1 a Kv1.6; Kv2.1; Kv3.1; Kv4.2; Kv4.3; Shaker IR e hERG). A peçonha bruta solúvel foi fracionada em cromatografia de troca iônica em coluna CM-Celulose-52 (2,5 cm x 63 cm), previamente equilibrada e eluída com tampão NH4HCO3 (pH 7,8). Essa primeira etapa cromatográfica permitiu a separação de 13 frações nomeadas de I XIII. A fração X foi submetida à cromatografia de fase reversa em sistema de cromatografia líquida de alta eficiência em que a toxina pura Ts15 pode ser obtida. Seu sequenciamento amino-terminal demonstrou que esse peptídeo possui 36 resíduos de aminoácidos estabilizados por 3 pontes dissulfeto. A massa molecular obtida por espectrometria de massa foi de 3956 e o pI predito pelo programa ProtParam foi de 8,86, no entanto, o pI determinado por focalização isolelétrica foi maior que 9,3. Os experimentos de eletrofisiologia utilizando as técnicas patch clamp e two microelectrode voltage clamp mostraram que a toxina Ts15 bloqueia preferencialmente os subtipos de canais para potássio Kv1.2 e Kv1.3 com IC50 de 196 ± 25 nM e 508± 67 nM respectivamente. Os ensaios de captação de neurotransmissores em sinaptosomas de cérebro de rato foram realizados adicionando 3H-GABA e 3H-Glu na presença e ausência de diferentes concentrações da toxina Ts15. Não foram observados efeitos nos canais para sódio em todas as concentrações testadas assim como na captação do GABA. Porém, foi observado aumento significante na captação do glutamato em todas as concentrações testadas, provavelmente como resultado de efeito secundário da ação da Ts15 em canais para potássio sensível a voltagem. Em conclusão, a Ts15 pode ser considerada um autêntico novo tipo de toxina escorpiônica, com afinidade para canais para potássio Kv1.2 e Kv1.3 e capaz de aumentar a captação de glutamato. Essa toxina é o único membro da nova subfamília -Ktx21 e portanto nomeada -Ktx21.1 / Scorpions are one of the most ancient groups of animals on earth. They are arthropods and belong to the class Arachinida and Order Scorpionida. The Buthidae family comprises the species that are really dangerous for human, including Tityus serrulatus that is responsible for most severe accidents in Brazil. T. serrulatus venom contains several neurotoxins that specifically act on sodium, potassium or calcium channels in excitable membranes, causing a massive release of neurotransmitters and leading to the stimulation of the autonomic nervous system. Since ion channels play important roles in many physiological processes, scorpion toxins have been used as tools for studies of the neurophysiological mechanisms involving voltage-gated ion channels and neurotransmitter release/uptake. Voltage-gated Na+ channel (Nav channel) toxins are mainly responsible of the harmful effects of scorpion venom and can be classified into two classes: and -neurotoxins. The -toxins retard Nav channel inactivation and induce a prolongation of the repolarization phase of the action potential. The -toxins shift the voltage dependence of Nav channel activation to more negative potentials that result in an increased tendency of the cell to fire spontaneously and repetitively. Voltage-gated potassium channel toxins (KTxs) are basic short chain peptides comprising 23-43 amino acid residues that can be cross-linked by 3 or 4 disulfide bridges. KTxs are classified into four large families: , , and . These peptides display varying selectivity and affinity for different Kv channel subtypes. In this work, a novel toxin from the T. serrulatus venom was isolated, biochemistry and pharmacologically characterized using a wide electrophysiological screening on 5 different subtypes of Nav channels (Nav1.4; Nav1.5; Nav1.6; Nav1.8 and DmNav1) and 12 different subtypes of Kv channels (Kv1.1 - Kv1.6; Kv2.1; Kv3.1; Kv4.2; Kv4.3; Shaker IR and hERG). The crude soluble T. serrulatus venom was fractionated by ion exchange chromatography on a CM-cellulose-52 column (2.5 cm x 63.0 cm), which was equilibrated and eluted with NH4HCO3 buffer (pH 7.8). This chromatography allowed the separation of 13 fractions which were named I to XIII. Fraction X was submitted to a reverse-phase C18 (0.46 cm x 25 cm) high performance liquid chromatography (RP-HPLC) and the pure toxin, Ts15, could be obtained. The amino acid sequence of this novel peptide showed that it contains 36 amino acids and is cross-linked by 3 disulfide bridges. The molecular mass of Ts15 (3956) was obtained by electrospray (ESI) triple-quadrupole mass spectrometry and its pI value (8,86) was predicted by ProtParam program. However, the pI determined by isoeletric focusing was greater than 9,3. Electrophysiological experiments using patch clamp and the two electrode voltage clamp technique, showed that Ts15 preferentially blocks Kv1.2 and Kv1.3 channels with IC50 value of 196 ± 25 and 508 ± 67 nM, respectively. Uptake assays were performed by adding 3H-GABA and 3H-Glu, in the absence (controls) or presence of different concentrations of Ts15, on isolated rat brain synaptosomes. No effect on Nav channels was observed, in all tested concentrations, as well as for GABA uptake. However, Ts15 induced a significant increase of the glutamate uptake, probably as a secondary effect of its action on Kv channels. In conclusion, Ts15 can be considered a bonafide novel type of scorpion toxin that presents high affinity by Kv1.2 and Kv1.3 channels and was able to increase the glutamate uptake. It is the unique member of the new -Ktx21 subfamily and therefore was named -Ktx21.1

Objetivos: Avaliar a implicação da doença periodontal (DP) avançada, e da expressão da NOS e sP dos tecidos gengivais inflamados, na intensidade de dor e na qualidade de vida de pacientes com dor crônica crânio-facial. Casuística e Métodos: foram avaliados e tratados 20 pacientes com queixas de dores crônicas crânio-faciais e DP (Grupo de Estudo), comparativamente com 20 pacientes que tinham somente DP (Grupo Controle). Todos os pacientes receberam tratamento cirúrgico periodontal. A avaliação foi realizada pré e pós-tratamento periodontal (7, 30 e 180 dias). Instrumentos de avaliação: ficha clínica EDOF-HC, Escala Visual Analógica (EVA), questionário de dor McGill, Índices de Placa (IP), Sangramento (IS), Profundidade Clínica de Sondagem (PCS) e de Inserção (PCI); questionário de qualidade de vida WHOQOL-bref e análise imunohistoquímica para a expressão da óxido nítrico sintase (NOS) e da substância P do tecido gengival inflamado. A avaliação da dor foi realizada por investigador independente. Resultados: Os grupos apresentaram evolução clínica semelhante pelos parâmetros da DP: IP (p=0,0934), IS (p=0,8657), PCS (p=0,1728) e PCI (p=0,7406) nos três momentos avaliados. Houve redução da EVA no Grupo de Estudo aos 30 dias (p<0,05) e 180 dias (p<0,05), comparativamente ao pré-operatório. Aos 180 dias houve melhora significativa das queixas iniciais (p=0,005 para o Grupo de Estudo e p = 0,027 para o Grupo Controle), comparativamente ao pré-operatório, entretanto, houve diferença significativa entre os dois grupos nos três momentos da avaliação, seja para o percentual de melhora (p<0,001), seja para os descritores de melhora Edof-HC (p=0,004 aos 30 dias e p=0,001 aos 180 dias). No Grupo de Estudo, houve redução significativa dos descritores afetivos de dor (questionário de dor McGill) aos 180 dias (p = 0,014). Os escores de qualidade de vida do Grupo de Estudo foram inferiores aos do Grupo Controle nos domínios psicológico e físico (p<0,001 e p=0,007, respectivamente). As expressões da nNOS e da iNOS foram maiores nas gengivas inflamadas do Grupo de Estudo (p<0,001 e p= 0,003, respectivamente) e a expressão da sP foi semelhante nos dois grupos (p=0,363). Conclusões: Houve redução da intensidade da dor crônica crânio-facial dos pacientes que receberam tratamento para doença periodontal avançada. A expressão da substância P foi semelhante nos tecidos gengivais inflamados dos dois grupos, mas a expressão da nNOS e iNOS foi superior na gengiva inflamada dos pacientes com dor crônica crânio-facial. Pelos dados deste estudo a Doença Periodontal avançada pode ter implicação nas queixas de dor dos pacientes com dor crônica crânio-facial. / Aims: To assess the implications of advanced periodontal disease (PD), and the expression of NOS and sP of inflamed gingival tissue, in the intensity of pain and the quality of life in patients with chronic craniofacial pain. Casuistic and Methods: Were evaluated and treated 20 patients with complaints of chronic craniofacial pain and DP (Study Group), compared with 20 patients who had only DP (Control Group). All patients received surgical periodontal treatment. The evaluation was performed at pre-operative and post-operative periodontal treatment (7, 30 and 180 days). Tools for evaluation: clinical record EDOF-HC, Visual Analogic Scale (VAS), McGill Pain Questionnaire, Scores of Plaque (IP), Bleeding (IS), Clinical Probing Depth (CPD) and Insertion (CPI), the quality of life questionnaire WHOQOL-Bref and immunohistochemical analysis for the expression of nitric oxide synthase (NOS) and substance P from inflamed gingival tissue. The assessment of pain was conducted by independent researcher Results: The groups had similar clinical evolution by parameters of the PD: IP (p=0.0934), IS (p=0.8657), PCS (p=0.1728) and PCI (p=0.7406) in the three moments evaluated. There was reduction in the VAS of Study Group at 30 days (p<0.05) and 180 days (p<0.05), compared to preoperative. At 180 days there was significant improvement of the initial complaints (p=0.005 for the Study Group and p=0.027 for the Control Group), compared to preoperative, but there was significant difference between the two groups in the three moments of assessment, for the percentage of improvement (p<0.001), and either for the improvement descriptors Edof-HC (p=0.004 at 30 days and p=0.001 for 180 days). In Study Group, there was significant reduction of pain affective descriptors (McGill Pain Questionnaire) to 180 days (p=0.014). The scores of quality of life of the Study Group were lower than the Control Group in the psychological and physical (p<0.001 and p=0.007, respectively). The nNOS and iNOS expressions were higher in inflamed gingival Study Group (p<0.001 and p=0.003, respectively) and the expression of sP was similar in the two groups (p=0.363). Conclusions: There was reduction in the intensity of chronic craniofacial pain of patients receiving treatment for advanced periodontal disease. The expression of substance P was similar in inflamed gingival tissue of the two groups, but the expression of iNOS and nNOS was higher in inflamed gingival of patients with chronic craniofacial pain. The data of this study show that advanced periodontal disease can have involvement in complaints of pain in patients with chronic craniofacial pain.

Introdução. A estimulação do córtex motor (ECM) tem sido utilizada para o tratamento de pacientes com síndromes neuropáticas dolorosas crônicas e resistentes a tratamentos farmacológicos convencionais. O córtex motor primário pode ser a estrutura mais rostral do neuroeixo relacionada ao sistema de modulação da dor, e a ECM provoca ativação neuronal na substância cinzenta periaquedutal (PAG). A PAG é um dos principais centros do sistema descendente supressor de dor e recebe aferências de diferentes regiões do encéfalo. Esse estudo investiga o efeito da estimulação do córtex motor sobre a liberação de neurotransmissores na PAG em modelo de dor neuropática, com o objetivo de investigar os mecanismos neuroquímicos responsáveis pelo feito terapêutico. Métodos. No primeiro experimento, ratos Wistar machos foram aleatoriamente divididos em três grupos. No primeiro grupo, os animais foram submetidos à indução de dor neuropática através da constrição crônica do nervo ciático, no segundo grupo, os animais foram submetidos apenas à exposição do nervo ciático e no terceiro grupo, nenhuma intervenção para indução de dor neuropática foi realizada. Todos os animais foram submetidos a implante unilateral epidural de eletródios de estimulação sobre a área do córtex motor correspondente a pata posterior e implante de cânula guia direcionada à PAG utilizando coordenadas estereotáxicas. Os animais foram avaliados no teste de hiperalgesia mecânica e uma sonda de microdiálise foi introduzida em direção a PAG. As amotras de microdiálise foram coletadas e a análise dos neurotransmissores foi feita em um sistema de cromatografia líquida de alta eficiência (HPLC). No segundo experimento, ratos Wistar machos com dor neuropática induzida na pata posterior foram submetidos a implante estereotáxico de cânula guia direcionada à PAG, e foi realizada micro-injeção de antagonista de glicina e/ou GABA na PAG, previamente a ECM, para avaliar a influência desses antagonistas no efeito analgésico induzido pela estimulação cortical. Resultados. Animais submetidos à indução de dor neuropática apresentaram reversão da hiperalgesia mecânica após ECM. A estimulação cortical induziu um aumento significativo nos níveis de glicina durante (aumento de 153%) e após MCS (134%). A concentração de GABA aumentou 145% durante a estimulação epidural. Os níveis de glutamato não mostraram alteração no microdialisado da PAG após ECM. Houve uma correlação estatisticamente significativa entre o posicionamento da sonda de microdiálise nas colunas lateral e dorsolateral da PAG e o aumento na liberação do neurotransmissor glicina nos animais do grupo CCI. A administração de antagonista de glicina na PAG reverteu o efeito antinociceptivo da estimulação cortical. A micro-injeção de antagonista de GABA na PAG reverteu parcialmente o efeito da ECM. Conclusões. Nossos resultados sugerem que os neutransmissores glicina e GABA, liberados na PAG durante ECM, contribuem para o efeito antinociceptivo da via analgésica descendente. Os resultados desse projeto poderão contribuir para a elucidação dos mecanismos do efeito antinociceptivo da ECM / Introduction. Motor cortex stimulation (MCS) has been used for the treatment of patients with chronic neuropathic pain syndromes that are resistant to conventional pharmacological treatment. The motor cortex may be the most rostral structure in the neuroaxis responsible for pain modulation, and MCS increase the neuronal activation of periaqueductal gray (PAG). The PAG is one of the main subcortical centers of the descending pain suppressor system, and receives inputs from several brain areas. This study investigates the effects of MCS on the release of neurotransmitters in the PAG in neuropathic pain model, in order to investigate the possible neurochemical mechanisms responsible for this effect. Methods. In the first experiment, Wistar male rats were randomly subdivided into three surgical groups. In the first group, induction of neuropathic pain was performed through chronic constriction injury of the right sciatic nerve, in the second group, the animals were submitted just to exposure of the sciatic nerve and in the third group, no intervention for induction of neuropathic pain was performed. All the rats underwent implantation of unilateral epidural electrodes on the motor area corresponding to the right hind paw. The animals were evaluated for mechanical hyperalgesia test and a microdialysis guide cannula was stereotaxically implanted into the PAG. The microdialysate samples were collected and the neurotransmitters analysis was performed by a high- performance (HPLC). In the second experiment, animals with induced neuropathic pain in the hind paw were submitted to a stereotaxic implantation of a guidewire directed to PAG, and a microinjection of glycine and/or GABA antagonist in the PAG before the ECM was performed, to evaluate the influence of these antagonists on the analgesic effect induced by the cortical stimulation. Results. Animals subjected to induction of neuropathic pain showed reversal of mechanical hyperalgesia after motor cortex stimulation. Cortical stimulation induced a significant increase in glycine levels during (153 % increase) and after MCS (134%). The GABA concentration increases 145 % during transdural stimulation. Glutamate levels showed no change in PAG microdialysate after MCS. There was a statistically significant correlation between the positioning of the microdialysis probe in the lateral and dorsolateral columns of the PAG and the increase in the release of the neurotransmitter glycine in the animals of the CCI group. Administration of glycine antagonist in PAG reversed the antinociceptive effect of cortical stimulation. Microinjection of GABA antagonist in PAG partially reversed the effect of MCS. Conclusions. Our results suggest that the neurotransmitters glycine and GABA, released in PAG during MCS, contribute to descending antinociceptive actions. The results of this project will contribute for the elucidation of the mechanisms of the antinociceptive effect of MCS, a phenomenon that has not been fully understood currently

Mon doctorat se focalise sur la synthèse, la caractérisation et les applications de matériaux poreux à base de silice, dioxyde de titane et zéolite. La silice poreuse, le dioxyde de titane et les zéolites ont été synthétisés en utilisant des méthodologies différentes. Des matériaux de silice fonctionnalisés ont été utilisés pour des applications en adsorption de colorant, ce qui est utile pour le traitement de l'eau. Un nouveau système réticulé et un nouveau dispositif ont été créés pour améliorer la capacité d'adsorption et pour le traitement d’une grande quantité d'eau. En tirant parti des pores, une nouvelle méthode de formation de clusters de Cu (0) a été établie. Les propriétés photophysiques ont été étudiées, en utilisant plusieurs sources de cuivre et différents matériaux poreux. L'utilisation du confinement pour la détection de petites molécules biologiques tels que les neurotransmetteurs a été démontrée. Plusieurs applications ont été développées sur la base de ces récepteurs de neurotransmetteurs artificiels. Un matériau de titane mésoporeux multifonctionnalisé a été utilisé pour les applications en biologie. En comparaison avec la silice, plus couramment utilisée, sa photoactivité pourrait apporter des avantages supplémentaires. Finalement, de nouveaux types de matériaux de type organotitanes hybrides ont été développés, et leurs propriétés photo-catalytiques ont été démontrées. / My PhD research focus on the synthesis, characterization and applications of silica, titania and zeolite based porous materials. Porous silica, titania and zeolite have been synthesized using different methodologies. Functionalized silica materials have been used for dye adsorption application which is useful for water treatment. A new cross-linked system and device have been created to enhance the adsorption ability and for large quantity of water treatment. By taking advantage of the pores, new method for Cu(0) cluster formation have been established. The photophysics of the Cu(0) clusters reduced from different copper source in different porous materials has been investigated. The use of the confinement for sensing has been demonstrated for small bio molecules, such as neurotransmitters. Several applications have been developed based on this artificial neurotransmitter receptors. Multi-functionalized mesoporous titania material has been used for bio-applications. Compare to the widely used silica material, its photoactivity could bring extra advantages. Finally, new types of hybrid organotitanium materials have been developed and their photocatalytic properties have been investigated.

Une grande partie des chimistes puisent leur inspiration auprès de la biologie. C’est le cas des chercheurs en chimie supramoléculaire, qui travaillent sur l’élaboration de récepteurs moléculaires synthétiques capables d’effectuer des reconnaissances moléculaires envers des substrats d’intérêt biologiques. Le but est ainsi de mimer l’activité des protéines naturelles, en vue d’applications cliniques.L’unité cyclotribenzylène (CTB) est une structure de symétrie C3 qui possède des propriétés complexantes intéressantes. Un CTB relié à une deuxième unité complexante par trois bras espaceurs constitue la famille des hémicryptophanes. Au cours de cette thèse, nous avons travaillé sur l’élaboration de récepteurs moléculaires basés sur cette unité CTB. Dans un premier temps nous avons développé une nouvelle méthode de synthèse d’hémicryptophane énantiopurs à l’échelle du gramme en vue d’effectuer des reconnaissances stéréosélectives de neurotransmetteurs chiraux. Nous avons ensuite développé des récepteurs CTB et hémicryptophanes combinant la chiralité du CTB et du groupement binaphtol. La configuration absolue des unités chirales ont été déterminées par une méthode de corrélation chimique. Ces récepteurs ont été utilisés pour réaliser des expériences de reconnaissance stéréosélective de saccharide et de bonnes diastéréosélectivités ont été obtenues. Enfin, nous avons travaillé sur l’élaboration d’une voie de synthèse d’hémicryptophanes fluorescents capables de subir des excitations bi-photoniques dans le but d’effectuer des expériences de suivi dans l’espace et dans le temps de substrats d’intérêt biologiques en milieu in-vivo. / Biology is an inspiration for chemists. Especially for the field of supramolecular chemistry, which one of the aim is to develop synthetic molecular receptors capable of molecular recognition to biological substrates, to mimic the activity of natural proteins for clinical applications.Cyclotribenzylene unit (CTB) is a C3-symmetry structure which present interesting recognition properties. When a CTB is connecting to another molecular unit by three spacers arms, it forms an hemicryptophane receptor. During this thesis, we worked on elaboration receptors based on CTB unit. First, a new way of enantiopure hemicryptophane synthesis on gram scale has been developed for stereoselective recognition of chiral neurotransmitters. Then receptors based on chirality of CTB and binaphthol unit has been developed. Assignment of absolute configuration of chiral unit was determined by a chemical correlation. Stereoselective recognition of carbohydrates by these receptors revealed good diastereoselectivity. Finally, a synthetic pathway leading to fluorescent hemicryptophanes was developed for bi-photonic excitation in order to realize in-vivo experiments of tracking biological substrates.

Células tronco mesenquimais de tecido adiposo, são uma promissora ferramenta para aplicações clínicas em terapias celular e regenerativa, em vista da facilidade de sua extração e da maior quantidade de células por unidade de massa de tecido quando comparado a outras fontes clássicas de células mesenquimais como medula óssea. O protocolo clássico de extração e purificação dessas células, depende de sua adesão em plástico e xeno-materiais demandando muito tempo para ser utilizado por médicos para auxiliar pacientes em procedimentos de emergência. Estas células são capazes se diferenciar em diversos tipos celulares, o que as torna boas candidatas para terapia celular, embora sua capacidade de transdiferenciação para fenótipos neuronais seja ainda discutida. Neste trabalho demonstramos um novo processo para isolar essas células na base de epitopos específicos expressos (assinatura molecular de superfície) utilizando aptâmeros como ligantes de alta afinidade para estes sitios. Aptâmeros, moléculas de DNA simples fita identificadas a partir de uma biblioteca combinatória de sequencias de DNA simples-fita foram identificados por ciclos reiterativos de seleção in vitro (SELEX) utilizando células tronco do lipoaspirado como alvo. Dois aptâmeros isolados, denominados APT9 e APT11, foram capazes de identificar subpopulações (15,8 e 23,7% respectivamente) dentre as células tronco mesenquimais (classicamente CD29+/CD90+/CD45-) e separá-las usando nano-partículas magnéticas acopladas aos aptâmeros. Além disso, seguindo uma indução para diferenciação neuronal, as células tronco mesenquimais passam a apresentar morfologia neuronal e apresentam expressão e atividade de diversos receptores de neurotransmissores, avaliados por PCR real-time e imageamento de variações da concentração de cálcio intracelular ápos stimulação com vários agonistas de receptores metatrópicos e ionotrópicos. Ao longo da diferenciação, os níveis transcricionais de mRNA de receptores de cininas (B1 e B2), nicotínicos (alfa 7), muscarínicos (M1, M3 e M4), glutamatérgicos (AMPA2 e mGluR2), purinérgicos (P2Y1 e P2Y4) e GABAergicos (GABA-A, subunidade 3) e da óxido nítrico sintase neural aumentaram quando comparados aos níveis das células não diferenciadas, enquanto que os níveis de expressão de outros receptores incluindo purinérgicos P2X1, P3X4, P2X7 e P2Y6 e muscarínico M5 diminuíram. Os níveis de atividade das classes dos receptores estudados, por imageamento de variações da concentração de cálcio intrac, aumentaram para a maioria dos agonistas analisados durante a diferenciação neuronal com exceção para respostas induzidas por glutamato e NMDA. Células diferenciadas expressavam altos níveis de antígenos específicos de neurônios como &#946;3-tubulina, NF-H, NeuN e MAP-2 indicando uma diferenciação em fenótipo neuronal bem sucedida. Desta maneira, esta tese, ao identificar aptâmeros, prove uma inovadora solução para médicos usarem as células tronco mesenquimais dentro de uma sala de cirurgia, através de um método que é capaz de purificar essas células em um tempo clínico viável, com pureza e sem contato com contaminantes. Além disso, nós mostramos aqui que com um protocolo como o proposto para diferenciação neuronal, nós poderíamos induzir essas células para se diferenciar em neurônios, através da ativação de fatores de transcrição específicos, levando às células tronco mesenquimais a serem possivelmente utilizadas em terapias celulares de reparo neuronal. / Adipose mesenchymal stem cells are promising tools for clinical applications in cellular and regeneration therapies, in view of easiness of extraction and higher amount of isolated stem cells per mass of tissue when compared to other classical mesenchymal stem cell sources including bone marrow. The classical protocol to extract and purify these cells, depending on plastic adherence and xeno-materials, is too time consuming to be used by physicians to help patients at emergency procedures. These cells are able to differentiate into various cell types, making them good candidates for cell therapy, however their capability for transdifferentiation into neural phenotypes is yet discussed. Here we show a novel process to isolate these cells using their surface molecular signature and aptamers, ssDNA molecules identified through the SELEX technique, denominated APT9 and APT11 that are able to identify subpopulations (15,8 and 23,7% respectively) within the mesenchymal stem cells (classically CD29+/CD90+/CD45-) and separate them using magnetic nano-particles attached to the aptamers. Moreover, following induction to neural differentiation, mesenchymal cells presents neuronal morphology and present expression and activity of several neurotransmitter receptors, as evaluated by real-time PCR and calcium imaging. During this process, mRNA transcription levels of bradykinin (B1 and B2), cholinergic (alpha 7), muscarinic (M1, M3 and M4), glutamatergic (AMPA2 and mGlu2), purinergic (P2Y1 and P2Y4) and GABAergic (GABA-A, subunit 3) receptors and neuronal nitric oxide synthase were augmented when compared to levels of undifferentiated cells, while the expression levels of other receptors including purinergic P2X1, P2X4, P2X7 and P2Y6 and muscarinic M5 receptors were down-regulated. Activity levels of the studied receptor classes, as studied by calcium imaging, increased for most of the agonists analyzed during the neuronal differentiation with the exception for glutamate- and NMDA-induced receptor responses. Differentiated cells expressed high levels of neuron-specific antigens such as &#946;3-tubulin, NF-H, NeuN and MAP-2, indicating a successful differentiation into neuronal phenotypes. This thesis, by identifying aptamers, provides a novel solution for physicians to use mesenchymal stem cells inside a surgery room, by using a method that are able to purify the cells in a clinical viable time, with purity and no contact with contaminats. Furthermore, we show here that with a protocol as provided for neuronal differentiation, we could induce these cells to differentiate into neurons, by activating specific transcription factors,making mesenchymal stem cells to possibly be used in neuronal repair cell therapies.

Recently, the medial habenula-interpeduncular (MHb-IPN) axis has been hypothesized to modulate anxiety although neuronal populations and molecular mechanisms regulating affective behaviors in this circuit are unknown. Here we show that MHb cholinergic neuron activity directly regulates anxiety-like behavior. Optogenetic silencing of MHb cholinergic IPN inputs reduced anxiety-like behavior in mice. MHb cholinergic neurons are unique in that they robustly express neuronal nicotinic acetylcholine receptors (nAChRs), although their role as autoreceptors in these neurons has not been described. nAChRs are ligand-gated cation channels that are activated by the excitatory neurotransmitter, acetylcholine (ACh), as well as nicotine, the addictive component of tobacco smoke. We expressed novel nAChR subunits that render nAChRs hypersensitive to ACh, ACh detectors, selectively in MHb cholinergic neurons of adult mice. Mice expressing these ACh detectors exhibited increased baseline anxiety-like behavior that was alleviated by blocking the mutant receptors. Under stressful conditions, such as during nicotine withdrawal, nAChRs were functionally upregulated in MHb cholinergic neurons mediating an increase in anxiety-like behavior. Together, these data indicate that MHb cholinergic neurons regulate anxiety via signaling through nicotinic autoreceptors and point toward nAChRs in MHb as molecular targets for novel anxiolytic therapeutics.

Despite the current understanding that sensorimotor circuits function through the action of transmitters and modulators, we have a limited understanding of how the nervous system directs the flow of information necessary to orchestrate complex behaviors. In this dissertation, I aimed to uncover how the nervous system coordinates these behaviors using the escape response of the soil nematode, Caenorhabditis elegans, as a paradigm. C. elegans exhibits a robust escape behavior in response to touch. The worm typically moves forward in a sinusoidal pattern, which is accompanied by exploratory head movements. During escape, the worm quickly retreats by moving backward from the point of stimulus while suppressing its head movements. It was previously shown that the biogenic amine tyramine played an important role in modulating the suppression of these head movmemetns in response to touch. We identified a novel tyramine-gated chloride channel, LGC-55, whose activation by tyramine coordinates motor programs essential for escape. Furthermore, we found that changing the electrical nature of a synapse within the neural circuit for escape behavior can reverse its behavioral output, indicating that the C. elegans connectome is established independent of the nature of synaptic activity or behavioral output. Finally, we characterized a unique mutant, zf35 , which is hyperactive in reversal behavior. This mutant was identified as a gain of function allele of the C. elegans P/Q/N-type voltage-gated calcium channel, UNC-2. Taken together, this work defines tyramine as a genuine neurotransmitter and completes the neural circuit that controls the initial phases of the C. elegans escape response. Additionally, this research further advances the understanding of how the interactions between transmitters and ion channels can precisely regulate neural circuit activity in the execution of a complex behavior.

The influx of calcium through N-type calcium channels (N-current) affects a myriad of neuronal functions. These include the triggering of synaptic release of neurotransmitter, adjustment of membrane potential and changes in gene transcription. N-channels are highly modulated proteins, so that N-current is attenuated or potentiated in response to environmental changes. In turn, the modulation of N-current has a direct effect on the downstream events, making the N-channel a focal point in neural signaling, and its modulation a mechanism for short term plasticity. The modulation of N-current by M1 muscarinic receptors (M1Rs) is of particular interest for several reasons. The M1R is instrumental in both cognition and memory formation as indicated by studies using either pharmacological agents aimed at M1Rs or knockout animals lacking M1Rs. Clinically, the M1R is an important target in the treatment of Alzheimer’s disease. Thus, like the N-channel, the M1R is an important element of neural signaling. Moreover, the stimulation of M1Rs affects N-current by through signaling pathways which despite being studied for decades, are not completely understood. For my dissertation I have investigated of M1R signaling on N-current using electrophysiological recordings of N-current from freshly dissociated neurons and from HEK cells expressing N-channels and M1Rs. Asking how one receptor affects one type of calcium channel would seem to be a simple question. However, the answer has many facets. Since M1Rs have multiple downstream effects and N-channels are highly modulated proteins, stimulation of M1Rs initiates several different pathways which modulate N-current. This thesis aims to unravel some of the complexities of the interactions of two vital components of neuronal signaling. Here I present the results of studies elucidating three different actions of M1signaling of N-current modulation. The first study I present here examines the effect of N-channel subunit composition on modulation of N-current. The stimulation of M1Rs in superior cervical ganglion (SCG) neurons elicits a distinct pattern of modulation; inhibiting N-current elicited by strong depolarizations and enhancing current elicited by lesser depolarizations. Thus M1Rs cause two simultaneous modulatory effects on N-current; increasing voltage sensitivity and decreasing overall conductance. I found the expression of the N-channel’s β subunit (CaVβ) determines the observed effect. Specifically when the isoform CaVβ2a is expressed M1 stimulation elicits enhancement without inhibition. Conversely, when CaVβ1b, CaVβ3, or CaVβ4 are expressed M1 stimulation elicits inhibition with out enhancement. These results fit a model in which both the enhancing and inhibiting effects of M1stimulation occur in all channels, but typically inhibition dominates. CaVβ2a blocks inhibition unmasking latent enhancement. Moreover, using mutants and chimeras I found palmitoylation of CaVβ2a at the N-terminus plays a key role in blocking inhibition. My findings predict the expression and localization of different CaVβ isoforms would dramatically alter modulation of N-current and thus may represent a previously unrecognized form of plasticity. The inhibition of N-current by M1Rs is controversial. It has been proposed recently that inhibition is directly attributable to the depletion of phosphatidylinositol-4,5-bisphosphate [PtdIns(4,5)P2] during M1 stimulation. However, in our lab, we have found arachidonic acid (AA) release, which occurs subsequent to PtdIns(4,5)P2 hydrolysis, is both necessary and sufficient to elicit inhibition. Therefore, in a second study, I tested the effect of CaVβ expression on N-current during exogenous AA application and found a pattern of modulation identical to M1R stimulation. Furthermore, I took part in a collaborative project identifying the AA producing enzyme, diacylglycerol lipase (DAGL), to be a necessary component of the inhibitory pathway elicited by M1Rs. These findings provide increased evidence for AA release being a key factor in the M1R stimulated pathway of inhibition. Moreover, these discoveries identify the expression of CaVβ2a and use of specific DAGL inhibitors as a molecular and pharmacological strategy to block inhibition of N-current, respectively. These tools allow the dissection of downstream effects of M1R stimulation, so that other modulatory effects may be observed. The phosphorylation of N-channels by protein kinase C (PKC) blocks inhibition of current brought on by G-protein β and γ subunits (Gβγ) binding directly to the channel. Relief of Gβγ inhibition by other means has been identified as a mechanism of short term plasticity. M1Rs are known to simulate PKC, but a connection between M1Rs and PKC phosphorylation of Nchannels had not been demonstrated. I hypothesized that PKC stimulation may be occluded by other downstream effects of M1Rs. Therefore in a third study, I used a pharmacological approach on SCG neurons to dissect the PKC activating pathway from the other downstream effects of M1 stimulation. I observed modulation of N-current indicating a loss of Gβγ&#; inhibition, thus consistent with PKC phosphorylation of channels. This conclusion reveals another aspect of M1 modulation, which can function as a means of short term plasticity.