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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
101

Participação do sistema endocanabinóide nas respostas comportamentais, hormonais e neuronais induzidas pela sobrecarga salina / Participation of the endocannabinoid system in behavioral, hormonal and neural responses induced by salt load

Fernanda Maria Veanholi Vechiato 10 April 2014 (has links)
O sistema endocanabinóide (eCB) tem sido reconhecido como um importante modulador da homeostase energética e recentemente estudos o apontam como um possível integrador da homeostase hidroeletrolítica. Estudos recentes do nosso laboratório demonstraram a participação do receptor canabinóide do tipo 1 (CB1R) no controle da secreção neurohipofisária em resposta a expansão hipertônica do volume extracelular. Dessa forma, o presente trabalho visou esclarecer a participação do sistema eCB, particularmente do CB1R, nas respostas neuronais, neuroendócrinas e comportamentais induzidas pela sobrecarga salina de 4 dias (SS). Uma vez que os animais em SS apresentam hipofagia induzida pela hiperosmolalidade, buscou-se avaliar as vias de integração do controle da homeostase energética e do balanço hidroeletrolítico por meio da introdução de um grupo em dieta pareada (pair fed, PF). De forma a investigar a hipótese acima, utilizou-se como ferramenta farmacológica o agonista seletivo CB1R, araquidonil-2-cloroetilamida (ACEA - 0,1g/5L), administrado por via intracerebroventricular (icv). Inicialmente, nosso trabalho mostrou que a SS promoveu aumento da expressão de CB1R tanto nos núcleos supra-óptico (NSO) e paraventricular (NPV) do hipotálamo quanto em estruturas da lâmina terminal [órgão subfornicial (SFO), o órgão vasculoso da lâmina terminal (OVLT) e o núcleo pré-óptico mediano (MnPO)]. Tais observações foram reforçadas pela análise microscópica destas regiões cerebrais por imunofluorescência, que evidenciou aumento da imunomarcação para CB1R no NPV, NSO e SFO em animais submetidos a SS. Estes resultados também mostraram que a maioria dos terminais pré-sinápticos CB1R-positivos estão localizados predominantemente na porção ventral do NSO, na qual predominam neurônios vasopressinérgicos. Os dados mostram ainda que todas as respostas induzidas pela SS foram revertidas após a reintrodução dos líquidos (RL, água e NaCl 0,3M). Já no grupo PF, não foram observadas alterações na expressão de CB1R em nenhuma das áreas avaliadas. No entanto, após a RL, os animais PF apresentaram hipoosmolalidade plasmática e aumento da expressão de CB1R na LT, sendo este último efeito aparentemente mediado por um aumento da expressão deste receptor no SFO. Em animais normoidratados, a administração central de ACEA produziu um aumento significativo na ingestão alimentar, sendo esta resposta ausente nos animais submetidos a SS, apesar do aumento da expressão de CB1R no hipotálamo verificada neste grupo. Entretanto, o pré-tratamento com ACEA foi capaz de potencializar a ingestão de água induzida pela SS, não produzindo efeitos significativos sobre este parâmetro no grupo PF. Este estudo demonstrou ainda que a SS não alterou as concentrações plasmáticas de angiotensina II (ANGII), porém promoveu aumento signficativo nas concentrações plasmáticas de corticosterona, vasopressina (AVP) e ocitocina (OT), além de diminuir a secreção de peptídeo natriurético atrial (ANP). Em animais submetidos a SS, o prétratamento com ACEA potencializou a secreção de corticosterona e preveniu o aumento da secreção de AVP e OT. Por outro lado, não foram observados efeitos da administração de ACEA sobre a secreção de ANP e ANGII induzida pela SS. Após a RL, o grupo SS apresentou normalização das concentrações plasmáticas hormonais, não sendo observados quaisquer efeitos da administração de ACEA nestas condições experimentais. No grupo PF, por sua vez, após a RL foi observada diminuição na secreção de OT e aumento nas concentrações plasmáticas de ANGII, efeitos estes não alterados pelo pré-tratamento com ACEA. Em conjunto, nossos dados sugerem que o CB1R participa ativamente das respostas homeostáticas comportamentais e neuroendócrinas desencadeadas pela SS, sendo estas respostas especificamente relacionadas ao controle da homeostase hidrossalina e não secundárias à hipofagia induzida pela hiperosmolalidade. Desta forma, conclui-se que a participação do CB1R na homeostase hidroeletrolítica ocorre em paralelo e independentemente da modulação exercida por este receptor sobre a homeostase energética. / The endocannabinoid system (eCB) has been recognized as an important modulator of energy homeostasis and recent studies suggest that this system may play a possible integrator role on hydromineral homeostasis. Recent studies from our laboratory demonstrated the involvement of the type 1 cannabinoid receptor (CB1R) in the control of neurohypophyseal secretion in response to hypertonic extracellular volume expansion. Therefore, the present study aimed to clarify the involvement of the ECB system, particularly of CB1Rs, in neuronal, neuroendocrine and behavioral responses induced by 4 days of salt load (SS). Since the animals submitted to SS exhibit a well known state of hyperosmolality-induced hypophagia, we attempted to evaluate the integrated control of energy homeostasis and hydroelectrolytic balance through the introduction of a paired diet group (pair fed, PF). In order to achieve these goals, this study employed as a pharmacological tool the CB1R selective agonist, arachidonoyl-2\'-chloroethylamide (ACEA-0.1g/5L), administered intracerebroventricularly (icv). Initially, our work showed that SS increased the expression of CB1R in both supraoptic (SON) and paraventricular (PVN) nuclei of the hypothalamus, as well as in the structures of the lamina terminalis [subfornical organ (SFO), organum vasculosum of the lamina terminalis (OVLT) and median preoptic nucleus (MnPO)]. These observations were reinforced by the microscopic analysis of these brain regions by immunofluorescence, which showed increased immunostaining for CB1R in the PVN, SON and SFO in animals submitted to SS. These results also showed that most of the presynaptic CB1R-positive terminals are located predominantly in the ventral part of the SON, which is characterized by the presence of vasopressinergic neurons. The data also showed that all SS-induced responses were reversed after reintroduction of fluids (RF, water and 0,3M NaCl). On the other hand, no changes in the expression of CB1R in any of the evaluated areas were observed in the PF group. However, after RF, PF animals showed hypoosmolality and increased expression of CB1R in the LT, being the latter effect apparently mediated by increased expression of this receptor in SFO. In euhydrated animals, the central administration of ACEA produced a significant increase in food intake, being this response absent in animals submitted to SS, despite the increased expression of CB1R in the hypothalamus observed in this group. However, pretreatment with ACEA was able to potentiate SS-induced water intake, producing no significant effect on this parameter in the PF group. This study also demonstrated that SS did not alter plasma concentrations of angiotensin II (ANG II), but significantly increased plasma concentrations of corticosterone, vasopressin (AVP) and oxytocin (OT), and decreased the secretion of atrial natriuretic peptide (ANP). In animals submitted to SS, pretreatment with ACEA enhanced the secretion of corticosterone and prevented the increased secretion of AVP and OT. Moreover, no effect of ACEA was observed on the SS-induced ANG II and ANP secretion. After RF, the SS group showed normalization of hormonal plasma concentrations, and no effects of ACEA administration were verified under these experimental conditions. After RF, the PF group exhibited a decrease in OT secretion and increased plasma concentrations of ANG II, effects that were not altered by pretreatment with ACEA. Taken together, our data suggest that CB1Rs actively participate in behavioral and neuroendocrine homeostatic responses triggered by SS, and that these responses were specifically related to the control of hydromineral homeostasis and not secondary to the hyperosmolality-induced hypophagia. Therefore, we conclude that the involvement of CB1R in electrolyte homeostasis occurs in parallel and independently of the modulation exerted by this receptor on energy homeostasis.
102

Nouvelles stratégies pour prévenir les effets néfastes des psychostimulants : l'exposition à l'environnement enrichi et la stimulation du système cannabinoïde endogène / New strategies to prevent negative effects of psychostimulants : exposure to enriched environment and stimulation of the endogenous cannabinoid system

Nader, Joëlle 16 November 2012 (has links)
L'étude de l'impact des facteurs environnementaux sur les effets à long-terme des psychostimulants a montré que des facteurs négatifs, comme le stress, augmentent le risque de développer une addiction, alors que des facteurs positifs, comme l'exposition à des conditions stimulantes, le réduisent. Une partie de cette thèse a consisté à rechercher les mécanismes neurobiologiques et cellulaires qui sous-tendent cette influence environnementale. Ainsi, l'exposition d'animaux à un environnement enrichi (EE), qui procure des conditions stimulantes, diminue leur niveau d'anxiété, un effet qui serait en partie lié à la régulation de gènes appartenant au système cannabinoïde endogène (SCE) dans des régions impliquées dans la réactivité au stress (article 1). Par ailleurs, nos travaux ont mis en évidence des limites de l'exposition à l'EE : quand celle-ci est interrompue, ses effets bénéfiques sont perdus et la vulnérabilité à la cocaïne est même augmentée. Ceci s'expliquerait par l'apparition d'un état émotionnel négatif, associé à une activation du facteur CREB dans l'amygdale étendue, une région carrefour entre la récompense et le stress (article 2). Nous nous sommes aussi intéressés à la toxicité de la méthamphétamine et à sa modulation par le SCE, pour lequel des propriétés neuroprotectives avaient déjà été suggérées. Ainsi, une stimulation pharmacologique du SCE permet de prévenir la neurotoxicité dopaminergique induite par la méthamphétamine (article 3). Nos résultats soulignent la complexité d'utilisation des manipulations environnementales et mettent en lumière les capacités protectives du SCE contre la dépendance et la neurotoxicité engendrées par les psychostimulants. / Studies of the impact of environmental factors on the long-term effects of psychostimulants have shown that negative factors, such as stress, increase the risk of developing drug addiction, while positive factors, such as exposure to stimulating conditions, reduce it. The first aim of this thesis work was to look for the neurobiological and cellular mechanisms that underlie this environmental influence. We found that exposure of animals to stimulating enriched environments (EE) reduces anxiety levels, an effect that may be partly related to the regulation of genes belonging to the endogenous cannabinoid system (ECS) in regions involved in stress reactivity (Article 1). In addition, our work has highlighted some limitations of the exposure to EE since discontinuation of enrichment results not only in the loss of its beneficial effects but also in increased vulnerability to cocaine. This effect is associated with emotional distress associated and changes in the activity of the transcription factor CREB in the extended amygdala, an interface region between reward and stress processes (Article 2). We also investigated whether ECS, for which neuroprotective properties have already been suggested, could reduce the brain toxicity induced by methamphetamine. We found that pharmacological stimulation of ECS provides protection against the methamphetamine-induced dopaminergic neurotoxicity (Article 3). Our results highlight the complex consequences of environmental conditions on brain and behavior and highlight the protective role of ECS against both addiction and neurotoxicity induced by psychostimulants.
103

Mechanismus ovlivnění signalizace kanabinoidního receptoru 1 interagujícími proteiny / Role of proteins associated with the Cannabinoid receptor 1 in endocannabinoid signaling

Vozárová, Denisa January 2017 (has links)
To preserve homeostasis and proper function in every living organism, it is important for cells to communicate with each other and their environment. Cells are constantly processing a huge amount of extracellular stimuli through proteins called receptors. Receptors can transduce the signal from extracellular to intracellular compartments. G- protein coupled receptors are the biggest group, in which also belongs Cannabinoid receptor type 1 (CB1R). Endocannabinoid system regulates many biological processes such as learning, food intake, and movement. Obesity is a serious issue nowadays and in cases of claryfing its molecular-genetic basis, there was found Src homology 3-domain growth factor receptor-bound 2-like (endophilin) interacting protein 1 (SGIP1). SGIP1 has a role in the regulation of energetic balance and its overexpression is leading to a development of obesity. SGIP1 was detected as an interaction partner of CB1R and it had been found that it is involved in internalization via clathrin-mediated endocytosis (CME). Key proteins for initiation and early phase of CME are FCHO1/2, with which SGIP1 shares high sequential homology. However, effect of SGIP1 on internalization of activated CB1R is inhibitory unlike FCHO1/2,wheras detailed mechanism of its function remains unclear. The aim of this...
104

Mechanismus ovlivnění signalizace kanabinoidního receptoru 1 interagujícími proteiny / Role of proteins associated with the cannabinoid receptor 1 in endocannabinoid signaling

Vozárová, Denisa January 2017 (has links)
To preserve homeostasis and proper function in every living organism, it is important for cells to communicate with each other and their environment. Cells are constantly processing a huge amount of extracellular stimuli through proteins called receptors. Receptors can transduce the signal from extracellular to intracellular compartments. G-protein coupled receptors are the biggest group, in which also belongs Cannabinoid receptor type 1 (CB1R). Endocannabinoid system regulates many biological processes such as learning, food intake, and movement. Obesity is a serious issue nowadays and in cases of searching for candidate molecules, there was found Src homology 3-domain growth factor receptor-bound 2-like (endophilin) interacting protein 1 (SGIP1). SGIP1 has a role in the regulation of energetic balance and its overexpression is leading to a development of obesity. SGIP1 was detected as an interaction partner of CB1R and it had been found that it is involved in internalization via clathrin-mediated endocytosis. SGIP1 is very homological with FCHO1/2 - important proteins which participate on early stages of endocytosis. Mechanism of inhibitory effect of SGIP1 on internalization remains unclear. The aim of this study is to clarify the role of distinct domains of SGIP1 in context of endocytosis. Key...
105

ADHD a užívání cannabinoidů jako forma sebemedikace / ADHD and cannabinoid use as a form of self-medication

Karchňáková, Zuzana January 2017 (has links)
BASIC POSTULATES: It is common the people affected by ADHD consume addictive substances, seeking relief from their sensations of motorical unease and to disturb their rationalising and thinking. Using these substances subjectively improves their abilities, reducing the undesired and unpleasant sensations emanating from the ADHD, possibly even creating enjoyable and desirable moods. The resulting problem is, this self-medication causes troubles in many aspects, detectable only gradually after longer periods of consumption. What starts as an effort to paliate the undesirable symptoms of ADHD and other effects thereof, progressively becomes seeking a solution to harmful consumption of marihuana and, in extreme cases, additiction to cannabinoids. OBJECTIVES: The main objective of this thesis is to find out what is the purpose of the people with ADHD diagnosis in taking cannabis. The focus as put on whether cannabis is used to treat the symptoms of ADHD or not (regardless of the diagnosis). It was also important to map what other addictive substances use if self-medication using cannabis. METHODS: Semi-structured was chosen for the purposes of research. The questionnaires were used from L. Adler ASRS -V1 Adler.1 - Report (Adult ADHD Self Scale). Cannabis Use Disorders Identification Test (CUDIT) from...
106

Zánětem vyvolané změny v expresi kanabinoidních receptorů v ptačím mozku / Inflammation-associated changes in cannabinoid receptor expression in avian brain

Divín, Daniel January 2020 (has links)
(EN) Research in interactions between the nervous and immune systems is focused mainly on mammals, while in other vertebrates, including birds, it remains neglected. Two types of cannabinoid receptors interconnect the nervous and immune systems: CB1, which is in mammals involved in regulation of neural processes, and CB2, which is in mammals involved in regulation of immune processes. However, little is presently known about the roles of these receptors in nervous and especially immune processes in birds. Therefore, in this work I focus on the expression of cannabinoid receptors in cognitively advanced bird species (parrots, passerines) during induced sterile peritoneal inflammation. Unlike passerines, parrots appear to lack the gene for CB2, which may affect the inflammation regulation. I have revealed no changes in the expression of these receptors during peritoneal inflammation neither in parrots, nor in songbirds. Nevertheless, the increase in expression of the proinflammatory cytokine IL- 1β in the brain in parrots confirms the importance of neuroimmune interaction and mutual influences along the gut-brain axis. This work suggests that even in birds, the central nervous system is affected by inflammation through the gut-brain axis. The expression of cannabinoid receptors does not change much...
107

Synthesis, Characterization and Biological Evaluation of Novel (S,E)-11-[2-(Arylmethylene) Hydrazono] Pyrrolo [2,1-c] [1,4] Benzodiazepine Derivatives

Mingle, David 01 August 2019 (has links)
Pyrrolo [2,1-c] [1,4] benzodiazepine (PBD) is a class of natural products obtained from various actinomycetes which have both anti-tumor and antibiotic activities and can bind to specific sequences of DNA. PBD-dilactam was initially produced using isatoic anhydride and (L)-proline which was then converted to the PBD-thiolactam using Lawesson's reagent. Reaction of thiolactam with hydrazine in ethanol afforded PBD-11-hydrazinyl. Condensation of 11-hydrazinyl PBD with aldehydes possessing various substitutions was performed to obtain (S,E)-11-[2-(arylmethylene) hydrazono] pyrrolo [2,1-c] [1,4] benzodiazepine derivatives. 1HNMR, 13C-NMR, DEPT, IR, GC-MS and X-ray crystallography were used for the characterization. Inhibition activity of the products were carried out using TEM-1, AmpC and P99 β-lactamases. A minimal inhibition growth of 25% was observed for one of the selected PBDs on cancer cell line. A promising result was observed on preliminary cannabinoid binding activity test on one of the compounds.
108

Rimonabant Is a Dual Inhibitor of Acyl CoA:Cholesterol Acyltransferases 1 and 2

Netherland, Courtney, Thewke, Douglas P. 01 August 2010 (has links)
Acyl coenzyme A:cholesterol acyltransferase (ACAT) catalyzes the intracellular synthesis of cholesteryl esters (CE). Both ACAT isoforms, ACAT1 and ACAT2, play key roles in the pathophysiology of atherosclerosis and ACAT inhibition retards atherosclerosis in animal models. Rimonabant, a type 1 cannabinoid receptor (CB1) antagonist, produces anti-atherosclerotic effects in humans and animals by mechanisms which are not completely understood. Rimonabant is structurally similar to two other cannabinoid receptor antagonists, AM251 and SR144528, recently identified as potent inhibitors of ACAT. Therefore, we examined the effects of Rimonabant on ACAT using both in vivo cell-based assays and in vitro cell-free assays. Rimonabant dose-dependently reduced ACAT activity in Raw 264.7 macrophages (IC50=2.9±0.38μM) and isolated peritoneal macrophages. Rimonabant inhibited ACAT activity in intact CHO-ACAT1 and CHO-ACAT2 cells and in cell-free assays with approximately equal efficiency (IC50=1.5±1.2μM and 2.2±1.1μM for CHO-ACAT1 and CHO-ACAT2, respectively). Consistent with ACAT inhibition, Rimonabant treatment blocked ACAT-dependent processes in macrophages, oxysterol-induced apoptosis and acetylated-LDL induced foam cell formation. From these results we conclude that Rimonabant is an ACAT1/2 dual inhibitor and suggest that some of the atherosclerotic beneficial effects of Rimonabant are, at least partly, due to inhibition of ACAT.
109

Antinociception Depends on the Presence of G Protein γ<sub>2</sub>- Subunits in Brain

Varga, Eva V., Hosohata, Keiko, Borys, Dariusz, Navratilova, Edita, Nylen, Anders, Vanderah, Todd W., Porreca, Frank, Roeske, William R., Yamamura, Henry I. 31 January 2005 (has links)
We have shown previously [Hosohata, K., Logan, J.K., Varga, E., Burkey, T.H., Vanderah, T.W., Porreca, F., Hruby, V.J., Roeske, W.R., Yamamura, H.I., 2000. The role of the G protein γ2 subunit in opioid antinociception in mice. Eur. J. Pharmacol. 392, R9-R11] that intracerebroventricular (i.c.v.) treatment of mice with a phosphorothioate oligodeoxynucleotide antisense to the γ2 subunit (Gγ2) of the heterotrimeric G proteins (antisense ODN) significantly attenuates antinociception by a δ-opioid receptor agonist. In the present study, we examined the involvement of Gγ2 in antinociception mediated by other (μ- or κ-opioid, cannabinoid, α2-adrenoreceptor) analgesic agents in a warm (55°C) water tail-flick test in mice. Interestingly, i.c.v. treatment with the antisense ODN attenuated antinociception by each analgesic agent. Missense phosphorothioate oligodeoxynucleotide treatment, on the other hand, had no effect on antinociception mediated by these agonists. The antinociceptive response recovered in 6 days after the last antisense ODN injection, indicating a lack of nonspecific tissue damage in the animals. These results suggest a pervasive role for the G protein γ2 subunits in supraspinal antinociception.
110

Herbal Marijuana Alternatives Investigation: K2 and Spice: A Masters Thesis

Rosenbaum, Christopher D. 30 December 2011 (has links)
Background Herbal marijuana alternatives (HMA), legal plant products adulterated with synthetic cannabinoid receptor agonists, represent a growing public health concern. Only a few case reports describe HMA and synthetic cannabinoid’s clinical toxicity. We describe an outbreak of HMA abuse primarily in the Midwest, the clinical presentation of HMA toxicity, and clinical and forensic testing. Methods During the course of ongoing surveillance for emerging drugs of abuse between November 2009 and August 2010, we retrospectively and prospectively identified a convenience sample comprising 81 cases of abuse of HMA products. Subject demographics, vital signs, lab results and urine were obtained (when available) and tested via gas chromatography mass spectrometry (GCMS) analysis. Samples of HMAs and synthetic cannabinoids were also analyzed via GCMS. Results HMA users were predominantly young males who inhaled HMAs. Analysis of their urine detected synthetic cannabinoid parent compound in one subject. GCMS analysis of synthetic cannabinoids established a reference library that confirmed the presence of synthetic cannabinoids in sampled HMA products. Conclusion HMA products were available in head shops, gas stations, and via the Internet. We have confirmed the presence of synthetic cannabinoids in these HMA products. The tachycardia, hypertension, agitation, anxiety, vomiting and hallucinations observed in this convenience sample are not readily explained by the presence of synthetic cannabinoids acting on CB1 and CB2 receptors. Further research must be done on HMA products and their abusers.

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