Alcohol represents the third leading cause of preventable death in the United States. Yet, despite its prevalent role in impeding human health, there is much to understand about how it elicits its effects on the body and how the body and brain change when an individual becomes physiologically dependent upon alcohol. The work presented herein represents an effort to elucidate the acute and chronic effects of alcohol on the nervous system. We investigate two specific protein pathways and their role in alcohol's effects on the body. The first begins with brain-derived neurotrophic factor (BDNF), which acts on TrkB, and ends with KCC2. We demonstrate that BDNF expression is increased in the VTA during withdrawal from chronic but not acute alcohol exposure and that this increase persists for at least seven days. Concomitantly, we demonstrate that the activation of GABAA channels on produces less inhibition of VTA GABA neurons in mice treated with chronic intermittent ethanol exposure than in alcohol naïve mice. This effect likewise persisted for at least seven days. We illustrate that BDNF has no apparent direct effect on VTA GABA neuron firing rate. The second pathway begins with the T cell marker CD5 and ends with the anti-inflammatory cytokine, IL-10. We demonstrate that in a genetic CD5 knockout (CD5 KO) mouse model both alcohol consumption as well as the sedative properties of alcohol are reduced. Since CD+ B cells secrete more IL-10 than CD5- B cells, we also demonstrate the effects of IL-10 on VTA neurons. We show that IL-10 has direct effects on VTA dopamine (DA) neurons by increasing their firing activity. We relatedly illustrate that IL-10 produces an increase in DA release in the nucleus accumbens (NAc). However, contrary to our hypotheses, we show that IL-10 produces conditioned place aversion rather than conditioned place preference in a place conditioning paradigm, suggesting that IL-10 might mediate pain-induced secretions of DA. Collectively, these results suggest two potential therapeutic targets to reduce alcohol consumption that need further validation. They also suggest a novel mechanism for the sedative effects of alcohol at moderate and high doses.

No description available.

No description available.

Alcohol represents the third leading cause of preventable death in the United States. Yet, despite its prevalent role in impeding human health, there is much to understand about how it elicits its effects on the body and how the body and brain change when an individual becomes physiologically dependent upon alcohol. The work presented herein represents an effort to elucidate the acute and chronic effects of alcohol on the nervous system. We investigate two specific protein pathways and their role in alcohol’s effects on the body. The first begins with brain-derived neurotrophic factor (BDNF), which acts on TrkB, and ends with KCC2. We demonstrate that BDNF expression is increased in the VTA during withdrawal from chronic but not acute alcohol exposure and that this increase persists for at least seven days. Concomitantly, we demonstrate that the activation of GABAA channels on produces less inhibition of VTA GABA neurons in mice treated with chronic intermittent ethanol exposure than in alcohol naïve mice. This effect likewise persisted for at least seven days. We illustrate that BDNF has no apparent direct effect on VTA GABA neuron firing rate. The second pathway begins with the T cell marker CD5 and ends with the anti-inflammatory cytokine, IL-10. We demonstrate that in a genetic CD5 knockout (CD5 KO) mouse model both alcohol consumption as well as the sedative properties of alcohol are reduced. Since CD+ B cells secrete more IL-10 than CD5- B cells, we also demonstrate the effects of IL-10 on VTA neurons. We show that IL-10 has direct effects on VTA dopamine (DA) neurons by increasing their firing activity. We relatedly illustrate that IL-10 produces an increase in DA release in the nucleus accumbens (NAc). However, contrary to our hypotheses, we show that IL-10 produces conditioned place aversion rather than conditioned place preference in a place conditioning paradigm, suggesting that IL-10 might mediate pain-induced secretions of DA. Collectively, these results suggest two potential therapeutic targets to reduce alcohol consumption that need further validation. They also suggest a novel mechanism for the sedative effects of alcohol at moderate and high doses.

Initialement découvert au cerveau, le Brain-derived neutrophic factor (BDNF) est un facteur de croissance dont les mécanismes de relâche et la signalisation ont été bien étudiés dans le système nerveux central. Il est aussi retrouvé en concentrations importantes dans la circulation où il est emmagasiné dans les plaquettes avec des niveaux pouvant atteindre 100 à 1000 fois ceux des neurones. Malgré l’abondance du BDNF dans les plaquettes, sa fonction dans la physiologie plaquettaire n’a jamais été étudiée. Le but de ce projet était donc d’investiguer le rôle du BDNF dans la fonction plaquettaire et les mécanismes de signalisation impliqués dans la réponse plaquettaire au BDNF. Lorsque les plaquettes sont isolées et re-suspendues dans un tampon physiologique dépourvu de protéines plasmatiques, le BDNF induit une agrégation plaquettaire complète et biphasique qui dépend des voies secondaires de l’agrégation. La neurotrophine NT4 ainsi qu’un anticorps activateur du récepteur TrkB ont tous les deux induit une agrégation plaquettaire similaire à celle du BDNF suggérant un récepteur commun, le TrkB. Par immunobuvardage, cytométrie en flux et microscopie électronique, nous avons pu confirmer que les plaquettes expriment une forme tronquée du récepteur TrkB, au niveau intracellulaire et à leur surface. Les tests fonctionnels nous ont mené à impliquer les voies de rhoGTPase Rac1, la protéine kinase C (PKC) et la voie phosphoinositide 3-kinase (PI3K)/Akt dans l’agrégation plaquettaire induite par le BDNF. Une fois activées par le BDNF, les plaquettes relâchent plusieurs cytokines proinflammatoires et proangiogéniques qui peuvent jouer un rôle important dans le maintien et la réparation de l’intégrité vasculaire. Parmi les agents relâchés, on retrouve des facteurs de croissances comme le PDGF et le VEGF, mais aussi des chimiokines comme l’IL8 et ENA-78. Finalement, lorsque les expériences d’agrégation ont été répétées en plasma riche en plaquettes, l’effet pro-agrégant du BDNF était perdu, possiblement via une liaison de BDNF avec la protéine plasmatique α2-macroglobuline (α2M). Cette liaison à α2M, suggérée par des expériences de co-immunoprécipitation, réduit la biodisponibilité du BDNF et pourrait aider à contenir la réponse plaquettaire au BDNF aux sites de lésions vasculaires. / The Brain-Derived Neutrophic Factor (BDNF) is a growth factor that was initially discovered in the brain. BDNF has both an autocrine and a paracrine role in neurons and its release and signaling mechanisms have been extensively studied in the central nervous system. Surprisingly, large quantities of BDNF have been reported in circulation, where it is essentially stored in platelets with concentrations reaching 100-1000-fold those of neurons. Despite this abundance, the function of BDNF in platelet biology has not been explored. Thus, this project sought to investigate the effect of BDNF on platelet function and the mechanisms underlying platelet responses to BDNF. In washed platelets, BDNF induced complete biphasic platelet aggregation that in part relied on amplification from secondary mediators. The low-affinity agonist neurotrophin-4 and an activating antibody raised against the canonical BDNF receptor TrkB induced similar platelet responses, implicating TrkB. Platelets express, both at their surface and in their intracellular compartment, a truncated form of TrkB lacking a tyrosine kinase domain. The BDNF-induced aggregation of washed platelets was prevented by inhibitors of the Rac1, PKC, and PI3K/Akt. Platelets exposed to BDNF secreted pro-angiogenic and pro-inflammatory cytokines, which may play a role in maintaining vascular homeostasis. Finally, in platelet-rich plasma, exogenous BDNF failed to induce aggregation and BDNF immunoprecipitates contained α2-macroglobulin immunoreactivity. Hence, platelets are rich in BDNF, which induce platelet aggregation via TrkB activation. The restriction of BDNF bioavailablility by plasma protein binding may serve to target BDNF-mediated platelet activation to sites of vascular injury.

No description available.

There is increasing recognition of the relationship between depression and obesity in the pediatric population and recently, there has been a focus on inflammation as a potential link. Both conditions are considered to be pro-inflammatory states, and certain inflammatory markers are linked to depression in obese adults and vice versa. Leptin has also been implicated in depression as a potential mediator between inflammation and depression. Brain derived neurotrophic factor (BDNF), which is associated with depression and obesity, is influenced by inflammation and leptin in animal models as well. Few studies have examined the interactions between depression, adiposity, and biological markers in obese youth and therefore, our objective was to explore the determinants of depression in obese youth in a clinical setting. We studied 244 youth aged 8-17 years (125 girls, 119 boys) at the time of entry to a weight management program, as part of a prospective, longitudinal study. The CES-DC depression-screening tool was used to assess depressive symptoms, and a participant was classified as having high depressive symptoms if the CES-DC score ≥15 or taking antidepressants. Questionnaires assessed socio-demographic factors and puberty while adiposity was measured using dual-energy X-ray absorptiometry (DXA). Inflammatory markers (IL-6, TNFα, CRP, IL-10), leptin, and BDNF were quantified by immunoassays. Of the 244 participants, 8 were on antidepressants and 88 (36.4%) met the criteria for high depressive symptoms. We confirmed previous findings that household income and body fat were important determinants of depressive symptoms. However for the first time, it was identified that leptin levels predicted CES-DC score independent of body fat. Neither inflammatory markers nor BDNF were significantly related to depression scores. Our findings suggest that leptin may mediate the relationship of adiposity and depression but it is uncertain if this is related to direct action or to the phenomenon of leptin resistance. / Thesis / Master of Science (MSc) / Obesity has a significant impact on depression in children and adolescents. Inflammation – the body’s response to injury – is measured through markers in the blood and leptin – the marker of body fat – have shown to be related to depression. Research indicates that depression influences these factors to act on obesity. However, research on the interactions of biological and socio-demographic factors with depression in youth with obesity is lacking. Therefore, our objective was to explore the impact of these factors on depression in obese youth entering into a weight management program. Using a depression-screening tool, we studied 244 youth under 18 years and confirmed that household income and body fat were important factors of depression. However for the first time, we found leptin influenced depression regardless of the amount of fat present suggesting that depression acts on obesity through leptin but it is uncertain how this occurs and further research is warranted.

<p>Valproic acid (VPA) is clinically utilized as an anti-convulsant and mood stabilizer, though its mechanism of action has not been fully elucidated.<strong> </strong>Evidence suggests an interaction between VPA and the melatonergic system as VPA up-regulated the melatonin MT₁ receptor subtype in rat C6 glioma cells. To determine if the observed effects can translate to an <em>in vivo </em>model, we investigated the effects of chronic VPA administration in a rat model on the expression of MT₁ and MT₂ receptors in the hippocampus. We also investigated the effect of chronic VPA treatment on the expression of the neurotrophic factors BDNF and GDNF in the rat hippocampus and striatum.</p> <p>(1) Animals were separated into two groups with the experimental group receiving VPA (4 mg/mL) for 17 days, and the control receiving vehicle. The hippocampus was dissected and MT₁, MT₂, BDNF and GDNF mRNA were analyzed with RT-PCR. (2) Animals were separated into three groups with the first group receiving VPA (4 mg/mL), the second receiving VPA (3 mg/mL) for 16 days, and the control receiving vehicle. MT₂ mRNA in the hippocampal subregions were analyzed with in situ hybridization.</p> <p>VPA induced the expression of MT₁ and MT₂ mRNA in the hippocampus in the experimental group compared to the control group. VPA also increased MT₂ mRNA expression in the subregions of the hippocampus. Additionally, BDNF and GDNF mRNA expression were increased in the VPA treatment group.</p> <p>These findings raise the interesting question of whether the diverse clinical effects of VPA involve an interaction with the melatonergic system.</p> / Master of Science (MSc)

Smith-Magenis syndrome (SMS) is a complex disorder caused by haploinsufficiency of RAI1 and characterized by sleep disturbances, behavioral abnormalities, mental retardation, and obesity in teens and adults. Rai1+/- mice are obese after 20 weeks. Dup(17)(p11.2) syndrome is a complex disorder associated with overexpression of RAI1. A transgenic mouse model of dup(17)(p11.2) syndrome overexpresses Rai1 and results in a mouse that is growth delayed. In order to characterize the obese phenotypes of mouse models of SMS and the role of RAI1 in obesity, daily food intake and serum levels of insulin, glucose, PPY, and leptin were measured; adiposity was studied by characterizing fat deposition; and gene expression was studied in the hypothalamus. These studies show that Rai1+/- mice are hyperphagic, consume more during the inactive light phase, and have altered satiety genes in the hypothalamus. Adiposity studies have shown WT females have a higher body fat content and visceral fat proportion than males, but Rai1-Tg and Rai1+/- females have similar fat deposition patterns as WT males. Hypothalamic gene expression studies show that many genes and pathways are affected by Rai1 and Rai1 dosage, including many genes associated with obesity and satiety.

Submitted by Marcos Anselmo (marcos.anselmo@unipampa.edu.br) on 2017-06-05T14:03:37Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) JEFFERSON ROSA DE MENEZES.pdf: 2848766 bytes, checksum: e87a7c0a040b93eb5052a1ea902c099e (MD5) / Approved for entry into archive by Marcos Anselmo (marcos.anselmo@unipampa.edu.br) on 2017-06-05T14:03:52Z (GMT) No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) JEFFERSON ROSA DE MENEZES.pdf: 2848766 bytes, checksum: e87a7c0a040b93eb5052a1ea902c099e (MD5) / Made available in DSpace on 2017-06-05T14:03:52Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) JEFFERSON ROSA DE MENEZES.pdf: 2848766 bytes, checksum: e87a7c0a040b93eb5052a1ea902c099e (MD5) Previous issue date: 2017-02-22 / A deprivação maternal é um potente estressor na fase inicial da vida de mamíferos, ocasionando diversos déficits cognitivos que se mantêm na vida adulta. Dentre os mecanismos envolvidos nestes déficits estão o desiquilíbrio oxidativo e as alterações em determinadas proteínas, como o fator neurotrófico derivado do cérebro (do inglês Brain-Derived Neurotrophic Factor, BDNF). Estes eventos podem ocorrer em diferentes regiões do no cérebro, entre elas o hipocampo, principal região responsável pela formação e consolidação das memórias. Esta dissertação investigou os efeitos de diferentes estratégias neuroprotetoras (exercício físico, suplementação com chá verde, e, enriquecimento ambiental) nos déficits de memória advindos da deprivação maternal. Para avaliar a função mnemônica, foi utilizado um modelo animal de DM (em ratos Wistar) e os testes de reconhecimento de objetos, esquiva inibitória e labirinto aquático de Morris. Para avaliar o balanço redox hipocampal quantificamos espécies reativas de oxigênio (EROs), espécies reativas ao ácido tiobarbitúrico (TBARS), níveis de glutationa (GSH) e capacidade antioxidante total (FRAP), além disso, determinamos a atividade da enzima acetilcolinesterase e a quantificamos os níveis de BDNF. Nossos resultados demonstram que o exercício físico e o chá verde são estratégias antioxidantes eficazes de neuroproteção em um modelo de DM. Também demonstram que o enriquecimento ambiental é capaz de reverter os efeitos deletérios oriundos da DM por meio do incremento dos níveis de BDNF. Estes resultados revelam a possibilidade da utilização dessas intervenções como estratégia de neuroproteção. / Maternal deprivation is a potent stressor in the early life of mammalian, leading to several cognitive deficits that remain until adulthood. Among the mechanisms involved in these deficits are the oxidative imbalance and the alterations in some proteins, such as Brain-Derived Neurotrophic Factor (BDNF), events that can occur in different brain regions, as the hippocampus, the main region responsible for the memory formation and consolidation. This master thesis investigated the effects of different neuroprotective strategies (physical exercise, green tea supplementation, and environmental enrichment) on memory deficits related to maternal deprivation (MD). To evaluate the mnemonic function was used an animal model of MD (using Wistar rats) and the object recognition, inhibitory avoidance and Morris water maze memory tests. To evaluate hippocampal redox balance we quantified the reactive oxygen species (ROS), the thiobarbituric acid reactive species (TBARS), the glutathione levels (GSH) and the total antioxidant capacity (FRAP), as well as determine the acetylcholinesterase activity and the BDNF levels. Our results show that physical exercise and green tea are effective neuroprotective antioxidant strategies in a MD model. They also demonstrate that environmental enrichment is capable to reverse the deleterious effects of MD by increasing BDNF levels. These results reveal the possibility of using these interventions as a neuroprotection strategy.