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The excitatory, ionotropic glutamatergic AMPA receptor is the most common membrane-bound receptor in the central nervous system. AMPARs and the NMDA receptors are central to synaptic plasticity, memory, and mechanisms of neurodegeneration. The AMPAR is an obligate heterotetramer, composed of subunits GluA1-4. Subunit permutation determines ion conductance, trafficking and other functional characteristics. Few available antibodies are subunit-specific, disabling researchers from accurately visualizing differential AMPAR subunit distribution in the nervous system. This study sought to visualize a novel monoclonal GluA1/2/3 antibody with functional avidity for three of four receptor subunits and to characterize the ultrastructural localization of these receptors using confocal and electron microscopy.

O Transtorno da Depressão Maior (MDD) é uma doença muito difundida em todo mundo e com uma alta prevalência, principalmente em mulheres. Transtornos de humor são recorrentes e ameaçam a vida, devido ao risco de suicídio. Apesar disso, a etiologia do MDD ainda é pouco entendida e diversas hipóteses foram desenvolvidas na tentativa de explicá-la. Uma delas está ligada ao estresse. Distúrbios no eixo hipotálamo-hipófiseadrenal (HPA) estão presentes em cerca 70% de pacientes com depressão. Ao buscar um melhor modelo animal para estudo do impacto do estresse no desenvolvimento da depressão, chegamos ao estresse leve crônico (CMS). Em estudos prévios desenvolvidos neste laboratório, observamos que há diferenças entre tipos de estressores e os mediadores secretados na resposta do eixo HPA, isto é, durante o estresse físico é secretado o mediador vasopressina, enquanto que no estresse psicológico, é secretado o mediador CRF; já nos estresses considerados mistos (como nado forçado), ambos os mediadores estão presentes. Assim, propusemos estabelecer protocolos de CMS baseados no protocolo original de Paul Willner, pesquisador que desenvolveu este modelo, empregando estressores do tipo físico ou psicológico, separadamente. O que observamos foi que nenhum dos dois tipos de estressores conseguiu levar os animais à anedonia (queda na preferência por sacarose). No entanto, ao observar o ganho de peso dos animais ao longo do tempo e o mapeamento cerebral com citocromo c oxidase, notamos que o estresse teve seu impacto no animais. Comparados a outros modelos de depressão, o CMS tem a premissa de desenvolver um estado depressivo nos animais antes do teste com drogas antidepressivas, fazendo com que tenha uma alta validade preditiva. Ele também pode incorporar outros endpoints para avaliar outros comportamentos, além da anedonia, que possam demonstrar o estado depressivo no animal. Por exemplo, observamos no mapeamento cerebral que a substância negra e a PAG estiveram mais ativas no estresse físico e elas podem estar implicadas na busca por recompensa e na modulação de dor, respectivamente. Concluímos que o modelo de CMS é apropriado, embora ainda necessite de estudos quanto à equivalência de intensidade de estressores / Major Depressive Disorder (MDD) is a widespread disease all over the world with a high prevalence, especially among women. Mood disorders are recurrent and life threatening, due to suicide risk. Despite those, MDD etiology is poorly understood and several hypotheses have been developed to try and explain it. One of them is connected to stress. Disorders on the hypothalamus-pituitary-adrenal (HPA) axis are present in up to 70% of patients with depression. While searching for a better animal model to study the impact that stress might have on depression onset, we came across the Chronic Mild Stress (CMS) model. During previous studies developed in this lab, weve observed that there are differences between types of stressors and mediators involved in the HPA axis response, i.e. during physical stress, the mediator secreted is vasopressin, whereas during psychological stress, the mediator is CRF; on mixed stress (like forced swim), both mediators are present. That way, we proposed to set up CMS protocols based on Paul Willner (the researcher who developed this model)s original one, employing physical or psychological stressors separately. None of the types of stressors were able to induce anhedonia (decrease in sucrose preference) in the animals. However, noticing the animals weight gain over time, and cerebral mapping with cytochrome c oxidase, we could see that stress had impact over the animals. Compared to other depression models, CMS has the presupposition of leading the animals to a depressive-like state before testing antidepressant drugs, which gives it a high predictive validity. The model can also incorporate different endpoints to assess other behaviors, besides anhedonia, that may show the animals depressive-like state. For instance, we observed in the brain mapping that substantia nigra and PAG were more activated in physical stress and they can be implicated in reward seeking and pain modulation, respectively. So, we conclude that the CMS model is appropriate, although it still needs more research regarding the intensity of stressors equivalence

A dieta intermitente (DI), quando não causa desnutrição, expõe os organismos a um estresse nutricional moderado que estimula as proteínas de estresse e os mecanismos de defesa do organismo, tornando-o mais resistente a estímulos tóxicos. A DI atua em vias associadas à sobrevivência celular e à inflamação, envolvendo com isso a modulação do NF-<font face=\"Symbol\">kB. Porém, pouco se sabe sobre os mecanismos moleculares associados a estes efeitos, assim como o envolvimento de vias como a do CREB e da WNT, além de sua correlação com a sinalização inflamatória. Este projeto tem como objetivo avaliar os efeitos da DI na cognição e hipocampo de ratos na ausência ou presença de LPS. Os resultados mostraram que a DI melhora o desempenho dos animais nos testes comportamentais labirinto de Barnes e esquiva inibitória. Ainda, a DI induz um aumento de pCREB e da sinalização canônica da WNT e promove o aumento da razão IL-10 / TNF e a diminuição dos níveis de RNAm do Tlr-4, Nosi e Cox-2 no hipocampo. Os dados sugerem que a DI induz um predomínio das vias de sinalização protetoras no SNC de ratos. / The intermittent fasting (IF) protocol, when it does not cause malnutrition, induces a moderate nutritional stress to the organism which stimulates the stress proteins and the body\'s defense mechanisms, making it more resistant to toxic stimuli. The IF seems to act by mechanisms associated with cell survival and inflammation, thereby involving NF-<font face=\"Symbol\">kB modulation. However, little is known about the molecular mechanisms involved, as well as the participation of CREB and WNT pathways and its correlation with inflammatory signaling. This study investigates the effects of IF on cognition and on rat hippocampus in absence or presence of LPS. The results showed that IF improved performance in Barnes maze and inhibitory avoidance behavioral tests. Also, IF induced both increase of pCREB and canonical WNT signaling pathway, and decrease in inflammatory mRNA markers levels, such as Tlr-4, iNos and Cox-2. In addition, IF can also increase IL-10 / TNF ratio levels. Our results suggest that IF induces a prevalence of protective signaling pathways in the central nervous system.

The dorsal anterior cingulate cortex (dACC) has been implicated in a broad range of cognitive and emotional functions, including the processing of negative emotion. Furthermore, abnormalities in dACC activity have been associated with anxiety and depression, disorders in which negative emotion is dysregulated. Thus, a better understanding of the precise contributions of the dACC to negative emotion could give us important insights into the neurobiological mechanisms underlying these debilitating neuropsychiatric disorders. However, despite extensive study of the dACC, its precise role in negative emotion is unclear. Instead there is mounting evidence that rather than being one functionally homogeneous region, subregions of the dACC may have distinct functional roles. This evidence is largely correlational, and interventional studies in experimental animals are required to address this. Accordingly, the work in this thesis causally assessed the contributions of two spatially distinct subregions of the dACC (rostral and caudal) to the regulation of the behavioural and cardiovascular correlates of negative emotion in the common marmoset (Callithrix jacchus). These dACC subregions were targeted with indwelling cannulae to enable pharmacological manipulations to be carried out in a range of tasks, used to assess distinct components of negative emotion, such as conditioned fear and anxiety. The findings suggest that the rostral dACC and the caudal dACC do indeed have distinct contributions to the expression of negative emotion and the regulation of anxiety, respectively. Furthermore, an assessment of the anterograde projections of these subregions provides anatomical support for the observed functional differences.

Thesis (M.A.)--Trinity Graduate School, 2000. / Abstract. Includes bibliographical references (leaves 47-59).

Stroke is one of the most common, and damaging, neurological afflictions. Stroke causes widespread and variable chronic effects, due to the limited regenerative ability of the adult brain. Altered gene expression induces neuronal changes necessary for plasticity-dependent recovery, effects which can be enhanced by growth hormone-based pharmaceuticals. These processes are driven by alterations in the informational capacity of the genome – changes driven by epigenetic regulators. Following experimental strokes, and treatment with EGF and EPO, this study shows that two epigenetic regulatory mechanisms, DNA methylation and microRNA regulation, are significantly altered, both in treated and untreated animals. Specifically, treatment induces a net global suppression of miRNA activity, which appears to modify the physical behaviour of neurons in domains ranging from plasticity and memory formation, growth and replication, and potentially even to neurological disease signalling. The confirmation of epigenetic alterations following a stroke indicates a future role for epigenetic neuro-pharmacology in stroke management. / x, [99] leaves : ill. (some col.) ; 29 cm

Dopamine D3 receptors (D3Rs) have been implicated in mediating behavioural sensitization to various drugs of abuse, but their role in ethanol (EtOH) sensitization has not been directly examined. Neil Richtand proposed a role for D3Rs in the modulation of sensitization by acting as an inhibitor of D1/D2 receptor-mediated behaviours, and several reports suggest D3Rs up-regulate in response to chronic drugs of abuse. In separate experiments, we examined EtOH sensitization in D3R knockout (KO) as well as in D1R and D2R KO mice. We also examined amphetamine sensitization in D3R KOs compared to wild type mice. We challenged C57Bl/6 and DBA/2 mice with a D3R agonist (PD128907) and antagonist (U99194A) to examine how acute and chronic D3R activation and inactivation may affect the induction and expression of EtOH sensitization. We investigated D1/D3R interactions in sensitized and control mice and examined whether EtOH sensitization leads to changes in D3R binding using [125I]-7-OH-PIPAT autoradiography. Results showed that D3R KOs, were resistant to EtOH but not to amphetamine sensitization. Chronic but not acute D3R blockade with U99194A inhibited the induction, whereas acute D3R activation with PD128907 attenuated the expression of EtOH sensitization. In our D1/D3R interaction study we observed that although PD128907 attenuated D1 agonist-induced hyperactivity with SKF81297, this effect was the same in sensitized and control animals, even though sensitized mice were more responsive to PD128907 than controls. This enhanced response, which suggests a functional up-regulation of D3Rs, was not accompanied by changes in D3R binding as indicated by autoradiography, and could mean that functional changes in the D3R associated with EtOH sensitization occur elsewhere than at the level of the membrane-bound receptor. Taken together, these results suggest a modulatory role for the D3R in EtOH but not amphetamine sensitization, where D3R activation attenuates the expression and D3R blockade prevents the induction of EtOH sensitization. These results are important because a better understanding of the role of the D3R in EtOH sensitization may help not only to identify some of the underlying neural mechanisms of sensitization, but also help in the identification of treatment strategies for patients that may be susceptible to alcohol abuse.

Dopamine D3 receptors (D3Rs) have been implicated in mediating behavioural sensitization to various drugs of abuse, but their role in ethanol (EtOH) sensitization has not been directly examined. Neil Richtand proposed a role for D3Rs in the modulation of sensitization by acting as an inhibitor of D1/D2 receptor-mediated behaviours, and several reports suggest D3Rs up-regulate in response to chronic drugs of abuse. In separate experiments, we examined EtOH sensitization in D3R knockout (KO) as well as in D1R and D2R KO mice. We also examined amphetamine sensitization in D3R KOs compared to wild type mice. We challenged C57Bl/6 and DBA/2 mice with a D3R agonist (PD128907) and antagonist (U99194A) to examine how acute and chronic D3R activation and inactivation may affect the induction and expression of EtOH sensitization. We investigated D1/D3R interactions in sensitized and control mice and examined whether EtOH sensitization leads to changes in D3R binding using [125I]-7-OH-PIPAT autoradiography. Results showed that D3R KOs, were resistant to EtOH but not to amphetamine sensitization. Chronic but not acute D3R blockade with U99194A inhibited the induction, whereas acute D3R activation with PD128907 attenuated the expression of EtOH sensitization. In our D1/D3R interaction study we observed that although PD128907 attenuated D1 agonist-induced hyperactivity with SKF81297, this effect was the same in sensitized and control animals, even though sensitized mice were more responsive to PD128907 than controls. This enhanced response, which suggests a functional up-regulation of D3Rs, was not accompanied by changes in D3R binding as indicated by autoradiography, and could mean that functional changes in the D3R associated with EtOH sensitization occur elsewhere than at the level of the membrane-bound receptor. Taken together, these results suggest a modulatory role for the D3R in EtOH but not amphetamine sensitization, where D3R activation attenuates the expression and D3R blockade prevents the induction of EtOH sensitization. These results are important because a better understanding of the role of the D3R in EtOH sensitization may help not only to identify some of the underlying neural mechanisms of sensitization, but also help in the identification of treatment strategies for patients that may be susceptible to alcohol abuse.

No description available.