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One of the few attributes common to almost all living organisms is an ability to generate and maintain endogenous rhythms, which are controlled by a biological clock. The processes, which recur with a period of about 24 hours, are known as the circadian rhythms. The circadian clock controls rhythms of molecular, physiological as well as behavioral processes and adapts their activity to regularly appearing changes in day and night or season. In case of mammals, central oscillator is located in the hypothalamic suprachiasmatic nuclei (SCN). The SCN clock entrains rhythms of peripheral oscillators located in cells of other tissues. The central oscillator itself is synchronized with external environment mainly by a light-dark cycle, however, other cues can entrain the SCN clock as well. For example, during prenatal development, entrainment of a fetal clock is entirely dependent on non-photic cues derived from maternal organism. This study aimed to investigate a mechanism of the communication between the maternal and fetal central oscillators. A hypothesis was tested whether maternal melatonin may play a role in entrainment of the circadian clock in the fetal SCN. Furthermore, a mechanism, how melatonin may entrain the fetal clock was investigated at molecular level. The results provided evidence, that...

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La pathologie athéromateuse avec ses complications cardio-vasculaires reste aujourd’hui une des principales causes de mortalité dans les pays développés. Dans ce contexte, l’élaboration de nouveaux bio-marqueurs de la maladie athéromateuse occupe une place importante. Les objectifs de ces bio-marqueurs sont : de définir les populations les plus à risque de développer une complication cardio-vasculaire, de stratifier les groupes de patients de manière à optimiser leur prise en charge clinique et thérapeutique , de dévoiler de nouvelles cibles thérapeutiques dans le traitement de la pathologie. Dans ce contexte, nous avons ciblé trois bio-marqueurs d’intérêt à savoir la longueur des télomères leucocytaires (LTL) et le niveau d’expression leucocytaire des gènes c-Fos (impliqué dans les processus inflammatoires et oxydatifs) et OGG1 (nécessaire à la réparation des lésions oxydatives de l’ADN). Nous avons donc dans une première partie de ce travail voulu vérifier l’hypothèse selon laquelle la LTL pouvait être préservée par la prise régulière de statine, une thérapeutique ayant déjà démontré ses bienfaits en terme de prévention primaire et secondaire des maladies cardio-vasculaires. De plus, nous nous sommes intéressés aux possibles relations entre les niveaux d’expression des gènes c-Fos et OGG1 et la LTL. Nous nous sommes placés dans un contexte de patients à haut risque cardiovasculaire que représentent les patients en phase aigue de l’infarctus du myocarde (IDM). Ce travail a permis de montrer que la prise régulière de statine pouvait préserver la longueur des télomères leucocytaires et ce particulièrement chez les sujets les plus jeunes (moins de 64 ans), suggérant un nouvel effet « pléïotrope » des statines. Ce travail a également permis d’identifier les gènes c-Fos et OGG1 comme étant des acteurs potentiels du maintien de l’intégrité des télomères. La seconde partie de notre travail a porté sur une étude plus approfondie du niveau de transcription du gène c-Fos en relation avec l’un des principaux facteurs de risque de la maladie athéromateuse que représente le statut tabagique chez des patients présentant une maladie coronaire. Ce travail a permis de mettre en évidence pour la première fois une relation entre le niveau d’expression de c-Fos et le statut tabagique des sujets, suggérant que l’une des voies possibles de toxicité du tabac pourrait faire intervenir les voies de signalisations impliquant c-Fos. Ainsi, ce travail de thèse a permis de mettre en évidence trois bio-marqueurs intéressants dans le domaine de la pathologie athéromateuse : 1- La longueur des télomères leucocytaires qui peut être une des voies d’action bénéfique des statines en prévention précoce des maladies cardio-vasculaires, 2- Le niveau d’expression du gène OGG1 comme étant un des acteurs potentiels du maintien de l’intégrité des télomères, 3- Le niveau d’expression du gène c-Fos comme marqueur cumulatif d’exposition tabagique et potentiel acteur des effets délétères du tabac. Restent à préciser les mécanismes cellulaires et moléculaires mis en jeu et ainsi développer des stratégies thérapeutiques adéquates afin d’optimiser la prise en charge des patients souffrant de pathologies athéromateuses. / Atherosclerosis with cardiovascular complications remains today one of the leading causes of death in developed countries. In this context, development of new biomarkers of atherosclerosis has an important place. Objectives of these biomarkers are: • to identify populations most at risk of developing cardiovascular complications, • to stratify patient groups to optimize their clinical management and therapeutic, • to reveal new therapeutic targets in the treatment of the disease. In this context, we identified three biomarkers of interest, leukocyte telomere length (LTL) and level of expression of leukocyte genes c-Fos (involved in inflammatory processes and oxidative) and OGG1 (necessary repair of oxidative DNA damage). We therefore first part of this study wanted to test the hypothesis that LTL may be maintained by regular use of statin therapy which has already demonstrated its benefits in terms of primary and secondary prevention of cardiovascular disease. In addition, we examined the possible relationship between gene expression levels of c-Fos and OGG1 and LTL. We placed in the context of patients at high cardiovascular risk posed by patients in acute phase of myocardial infarction (MI). This work has shown that regular use of statins could preserve leukocyte telomere length and particularly among the younger subjects (under 64), suggesting a new effect "pleiotropic" statin. This work has also identified the genes c-Fos and OGG1 as potential actors for the maintenance of telomere integrity. The second part of our work focused on further study of the level of transcription of c-Fos in connection with one of the main risk factors for atherosclerosis posed by smoking status in patients with coronary artery disease. This work has to show for the first time a relationship between the expression level of c-Fos and smoking status of subjects, suggesting that one possible way of tobacco toxicity may involve the signaling pathways involving c-Fos. Thus, this thesis has highlighted three biomarkers of interest in the area of atherosclerotic disease: 1. Leukocyte telomere length may be one way of beneficial action of statins in early prevention of cardiovascular disease, 2. The level of OGG1 gene expression as a potential actor for maintained the integrity of telomeres, 3. The level of expression of the gene c-Fos as a marker of cumulative smoking exposure and potential actor of deleterious effects of tobacco. Remains to clarify the cellular and molecular mechanisms brought into play and thus develop appropriate therapeutic strategies to optimize the management of patients with atherosclerotic disease.

A deeper understanding of both movement control and the effects of nociceptor inputs on our motor systems is critical for proper clinical diagnosis of musculo-skeletal dysfunctions and for development of novel rehabilitation schemes. In the jaw system, masticatory movements are produced by a central pattern generator (CPG) located in the brainstem. Considerable efforts have been made in deciphering this neuronal network. The present thesis contributes towards an increasingly detailed understanding of its essential elements, and presents a hypothesis of how deep somatic pain (i.e. muscle pain) may be evoked and interferes with the masticatory CPG circuitry. In Paper I, the expression of c-Fos-like protein was used as a molecular marker to visualize brainstem neurons that were active during induced fictive mastication in the anesthetized and paralyzed rabbit. Our findings provide a previously lacking detailed record of the neuronal populations that form the masticatory motor pattern. Certain cells were located in brainstem areas previously suggested to be involved in the masticatory CPG. However, it was a new finding that neurons in the dorsal part of the trigeminal main sensory nucleus (NVsnpr-d) may belong to this circuitry. Paper II focused on the discovered neurons in NVsnpr in an in vitro slice preparation from young rats.  Intracellular recordings allowed us to define two cell types based on their response to depolarizing current. Microstimulation applied to the trigeminal motor nucleus, its reticular border, the parvocellular reticular formation and the nucleus reticularis pontis caudalis, elicited postsynaptic potentials in 81% of the neurons tested. Responses obtained were predominately excitatory and sensitive to gluta-matergic antagonists DNQX or/and APV. Some inhibitory and biphasic responses were also evoked. Bicuculline methiodide or strychnine blocked the IPSPs indicating that they were mediated by GABAA or glycinergic receptors. About one third of the stimulations activated both types of neurons antidromically. Neurons in NVsnpr-d seem to gather all the conditions that can theoretically account for a role in masticatory rhythm generation. In Paper III, the masticatory model system was used to investigate the possible role of muscle spindle primary afferents in development of persistent musculoskeletal pain. Following intramuscular acidic (pH 4.0) saline injections of rat masseter muscles, in vitro whole cell recordings were done from jaw closing muscle spindle somata located in the trigeminal mesencephalic nucleus (NVmes). Compared to control neurons, the somata of afferents exposed to acid had more hyperpolarized membrane potentials, more hyperpolarized thresholds for firing, high frequency membrane oscillations and ectopic bursting of action potentials. These changes in membrane properties lasted for up to 35 days. Within the same time frame experi-mental animals showed hypersensitivity to touch on the skin covering the injected muscle. Similar saline injections also resulted in a significant increase of activity dependent c-Fos expression in NVmes neurons compared to controls. Immuno-fluorescence and lectin binding studies indicated that small-caliber muscle afferents containing known nociceptor markers (CGRP, SP, P2X3, TRPV1 and IB4) and expressing glutamate receptors are found close to the annulo-spiral endings of the NVmes afferents. Combined, our new observations support the hypothesis that excessive release of glutamate, within muscle spindles due to ectopically evoked antidromic action potentials, could lead to development of persistent musculoskeletal pain by activation and/ or sensitization of adjacent muscle afferent nociceptors.

Made available in DSpace on 2016-06-02T19:22:13Z (GMT). No. of bitstreams: 1 TeseRCV.pdf: 1865864 bytes, checksum: 07a6f9c430514b03de88b087935a28a4 (MD5) Previous issue date: 2005-07-06 / The lesion of central nucleus of amygdala (NCeA) decrease sodium intake, but not thirst, induced by angiotensin II and sodium depletion in furosemide model. In the present work we investigated the effect of lesion of NCeA on sodium intake induced by the water deprivation rehydration protocol (PHRP). Adult male Holtzman rats (260-320 g) housed for five days with water, 1.8% NaCl and regular food pellets received sham (n = 12) or eletrolytic lesion of NCeA (1 mA / 20 s): unilateral (n = 10) and bilateral (n = 8). The ingestion of water and 1.8% NaCl was recorded five days pre- and post-surgery. No significant alteration in daily water or sodium intake was produced after sham-lesion surgery. The uni- or bilateral lesions of NCeA reduced the daily 1.8% NaCl intake, but did not alter daily water intake. Seven days after surgery, water and 1.8% NaCl were removed and only food remained avaiable for 24 or 36 hours. Then, food was removed and water was offered for rehydration (2 hours), PHRP protocol. After partial rehydration with water, 1.8% NaCl and water was made avaiable and ingestion was recorded at 15, 30, 60 and 120 minutes (sodium appetite test). No significant alteration was observed in cumulative 1.8% NaCl or water at sodium appetite test in NCeA lesioned rats after PH24hRP. After PH36hRP, the bilateral lesion of NCeA reduced 1.8% NaCl intake for 3.4 + 1.7 ml/h compared with sham lesion (8.6 + 1.6 ml / h, p < 0.05). Water intake was not altered by NCeA lesion. There was an enhancement in need-induced 1.8% NaCl intake of intacts rats in response to repeated episodes of water deprivation. This enhancement occurred neither in the group with NCeA lesion nor in the group with sham lesion. The NCeA lesion also reduced the 1.8% NaCl intake induced by sodium depletion with furosemide and removal of ambient sodium, thus confirme the effects of amygdalar lesion already described in the literature. The integrity of NCeA is necessary for full expression of sodium appetite in the PHRP protocol. Water deprivation induced Fos expression in hypothalamics nuclei and cells groups of the lamina terminalis. Fos expression was reverted or did not change in different nuclei after rehydratation in PHRP protocol. We also investigated the effect of lesion in the NCeA on Fos expression in forebrain and pontine structures in response to 36 hours of water deprivation and subsequent rehydration that immediately precede Na+ intake. Rats (n = 6 per group), whith sham lesion (F) or bilateral lesion of NCeA, were submitted to to PH36hRP. Expression of Fos (as assessed by immunohistochemistry) in lamina terminalis or lateral parabrachial nucleus was not altered, but increased in medial parabrachial nucleus and parvocellular division of paraventricular nucleus of hypothalamus in NCeA lesioned rats. The increased neuronal activity in medial parabrachial nucleus may be related to the inibitory effect of NCeA lesion on sodium appetite. / A lesão do núcleo central da amígdala (NCeA) reduz o comportamento de ingestão de sódio, mas não a sede, induzido por angiotensina II e depleção de sódio no modelo de furosemida. No presente trabalho investigamos o efeito da lesão do NCeA na ingestão de sódio induzida no modelo de privação hídrica-reidratacão parcial (PHRP). Ratos Holtzman adultos (260-320 g) ambientados por cinco dias com água, NaCl 1,8% e ração foram submetidos a lesão fictícia (n=12) ou lesões eletrolíticas do NCeA (1 mA /20 s): unilateral (n = 10) e bilateral (n = 8). Foi medida a ingestão diária de água e NaCl 1,8% cinco dias antes e cinco dias após as lesões. A lesão fictícia não alterou a ingestão diária de água nem de NaCl 1,8%. Lesões uni- ou bilaterais do NCeA reduziram a ingestão diária de sódio e não alteraram a ingestão diária de água. Sete dias após as lesões, foram removidas a água e NaCl 1,8%, mas não a ração por 24 ou 36 horas. Então foi removida a ração e oferecida água por duas horas (modelo PHRP) e após a reidratação parcial, NaCl 1,8% e água foram oferecidos e medidos aos 15, 30, 60 e 120 minutos (teste do apetite ao sódio). Na privação hídrica de 24 horas, lesões do NCeA não alteraram a ingestão de NaCl 1,8% ou água no teste do apetite ao sódio após reidratação parcial, já na privação hídrica de 36 horas, a lesão bilateral do NCeA reduziu a ingestão de NaCl 1,8% para 3,4 + 1,7 ml / h em relação ao grupo com lesão fictícia (8,6 + 1,6 ml / h, p < 0,05), no teste do apetite após reidratação parcial. A ingestão de água não foi alterada pela lesão do NCeA. Houve incremento na ingestão regulatória de NaCl 1,8% em resposta a episódios repetidos de privações hídricas sucessivas em animais intactos. Este incremento não ocorreu em nenhum dos grupos com lesão do NCeA e nem mesmo no grupo com lesão fictícia. A lesão do NCeA reduziu também a ingestão de NaCl 1,8% induzida por depleção de sódio com furosemida e remoção de sódio ambiente, confirmando os efeitos da lesão amigdalar já descritos na literatura.. A integridade do NCeA é necessária para a expressão completa do apetite ao sódio no modelo PHRP em ratos, sendo importante para a ingestão regulatória de sódio. A privação hídrica induz expressão da proteína c-Fos em núcleos hipotalâmicos e estruturas da lâmina terminal. Essa expressão é revertida ou permanece inalterada em diferentes núcleos após reidratação no modelo PHRP. Este trabalho também investigou o efeito de lesões do NCeA na expressão do gene c-Fos em áreas prosencefálicas e pontinas em resposta a 36 horas de privação hídrica e subsequente reidratação que precede a ingestão de sódio. Ratos (n = 6 por grupo), com lesão fictícia (F) ou com lesão eletrolítica bilateral do NCeA (L), foram mantidos hidratados ou submetidos a privação hídrica e reidratação parcial, e tiveram os encéfalos perfundidos para detecção imunohistoquímica de neurônios expressando a proteína c-Fos. A expressão de c-Fos em estruturas da lâmina terminal, núcleo supra-óptico ou no núcleo parabraquial lateral não foi alterada e aumentou no núcleo parabraquial medial e porção parvocelular do núcleo paraventricular do hipotálamo em ratos com lesão bilateral do NCeA. A atividade neuronal aumentada no núcleo parabraquial medial pode estar relacionada ao efeito inibitório da lesão do NCeA no apetite ao sódio neste modelo.

Made available in DSpace on 2014-12-17T15:36:41Z (GMT). No. of bitstreams: 1 RuthnaldoRML_TESE.pdf: 6295823 bytes, checksum: 7a96da99950cb2a0427cd0d44be715d0 (MD5) Previous issue date: 2014-08-30 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / The pregeniculate nucleus (PGN) of the primate s thalamus is an agglomerate neuronal having a cap shaped located dorsomedially to the main relay visual information to the cerebral cortex, the dorsal lateral geniculate nucleus (GLD). Several cytoarchitectonic, neurochemical and retinal projections studies have pointed PGN as a structure homologous to intergeniculate leaflet (IGL) of rodents. The IGL receives retinal terminals and appears to be involved in the integration of photic and non-photic information relaying them, through geniculo-hypothalamic tract (TGH), to the main circadian oscillator in mammals, the suprachiasmatic nucleus (SCN) of the hypothalamus. Thus, the IGL participates in the control of the biological rhythm by modulating the activity of the SCN. Pharmacological and IGL injury studies conclude that it is critical in the processing of non-photic information which is transmitted to the SCN. Other studies have found that especially neurons immunoreactive to neuropeptide Y (NPY) respond to this type of stimulation, determined by its colocation with the FOS protein. Has not been determined if the PGN responds, expressing the FOS protein, to the non-photic stimulus nor the neurochemical nature of these cells. Thus, we apply a dark pulse in the specifics circadian phases and analyze the pattern of expression of FOS protein in PGN of the marmoset (Callithrix jacchus). We found that in all animals analyzed the FOS expression was higher in the experimental than in the control group. There was a higher expression of FOS when the dark pulse was applied during the subjective day between the groups. Still, a subregion of the PGN, known by immunoreactive to NPY, had a greater number of FOS-positive cells in relation to his other just close dorsal region. Our data corroborate the theory that the PGN and IGL are homologous structures that were anatomically modified during the evolutionary process, but kept its main neurochemical and functional characteristics. However, injury and hodological studies are still needed for a more accurate conclusion / O n?cleo pr?-geniculado (NPG) do t?lamo de primatas ? um aglomerado neuronal, em forma de capuz, localizado dorsomedialmente ao principal retransmissor de informa??es visuais para o c?rtex cerebral, o n?cleo geniculado lateral dorsal (GLD). Diversos estudos citoarquitet?nicos, neuroqu?micos e de proje??es retinianas t?m apontado o NPG como estrutura hom?loga ao folheto intergeniculado (FIG) de roedores. O FIG recebe terminais retinianos e parece estar envolvido na integra??o de informa??es f?ticas e n?o-f?ticas retransmitindo-as, atrav?s do trato geniculohipotal?mico (TGH), ao principal oscilador circadiano em mam?feros, o n?cleo supraquiasm?tico (NSQ) do hipot?lamo. Desse modo, o FIG participa no controle da ritmicidade biol?gica modulando a atividade do NSQ. Estudos farmacol?gicos e de les?o concluem que o FIG ? fundamental no processamento de informa??es n?of?ticas as quais s?o transmitidas ao NSQ. Outros trabalhos verificaram que, especialmente, neur?nios imunorreativos ao neuropept?deo Y (NPY) respondem a esse tipo de est?mulo, determinados por sua co-localiza??o com a prote?na FOS. Ainda n?o foi determinado se o NPG responde, expressando a prote?na FOS, a est?mulos n?o-f?ticos nem tampouco a natureza neuroqu?mica dessas c?lulas. Assim, aplicamos um pulso de escuro em fases circadianas espec?ficas e analisamos o padr?o de express?o da prote?na FOS no NPG do sagui (Callithrix jacchus). Verificamos que em todos os animais analisados a express?o de FOS foi maior em rela??o ao grupo controle. Houve uma maior express?o de FOS quando o pulso de escuro foi aplicado durante o dia subjetivo entre os grupos estudados. Ainda, uma sub-regi?o do NPG, sabidamente imunorreativa a NPY, apresentou um maior n?mero de c?lulas FOSpositivas em rela??o ? sua outra regi?o imediatamente mais dorsal. Os nossos dados corroboram com a teoria de que o NPG e o FIG s?o estruturas hom?logas que se modificaram anatomicamente durante o processo evolutivo, mas mantiveram suas principais caracter?sticas neuroqu?micas e funcionais. No entanto, estudos de les?o e hodol?gicos ainda s?o necess?rios para uma conclus?o mais precisa

Les marsupiaux naissent très immatures, mais doivent atteindre une tétine, sans aide de la mère, à laquelle ils s’attachent pour poursuivre leur développement. Des informations sensorielles sont nécessaires pour s’orienter vers la tétine, la trouver, et s’y attacher. Le système vestibulaire, associé au sens de l’équilibre, a été proposé comme pouvant guider les petits marsupiaux vers la tétine en agissant sur les réseaux moteurs spinaux. Diverses études des marsupiaux suggèrent que le développement de ce système pourrait être suffisamment avancé pour influencer les comportements moteurs chez les nouveau-nés, mais son fonctionnement n’a jamais été testé. Pour le faire, nous avons soumis des opossums âgés de P0 (jour de la naissance; postnatal 0) à P21 à des stimulations vestibulaires et traité les tissus de la tête par immunohistochimie pour révéler c-Fos, utilisé comme indicateur d’activité neuronale. Du marquage dans les noyaux vestibulaires a été observé seulement à partir de P15. Pour confirmer ces résultats, nous avons effectué deux types d’expériences de stimulation sur des préparations in vitro d’opossums et enregistré les réponses motrices induites. Ainsi, des élévations de la tête n’ont pas permis de déceler de réponse suite aux stimulations aux âges étudiés (P4-P12). Par contraste, des pressions mécaniques directement appliquées sur le labyrinthe afin de stimuler les organes vestibulaires ont entrainé des réponses à tous les âges testés (P1-P9). Nos résultats suggèrent que la fonction du système vestibulaire est limitée par la maturité de ses organes sensoriels, et qu’il n’influence pas la motricité des nouveau-nés d’opossum en conditions physiologiques avant environ la fin de la 2e semaine de vie, même si les voies nerveuses entre les organes vestibulaires et la moelle épinière semblent déjà établies à la naissance. / Marsupials are born very immature, but must nevertheless find a teat, unaided by the mother, to which they attach to pursue their development. Sensory inputs are necessary to find the teat and attach to it, but the senses involved are still under discussion. The vestibular system, responsible for the sense of balance, was proposed as influencing motor behavior of newborns in various marsupial species by an action on spinal motor networks. Studies in the opossum Monodelphis domestica suggest that the development of the vestibular system could be advanced enough to influence locomotion at birth but its functionality has never been tested. To do that, we subjected intact opossums aged P0 (Postnatal day 0 ; day of birth) to P21 to vestibular stimulations and immunohistochemically processed their brain tissues to reveal c-Fos, used as a marker of neuronal activity. Immunoreactivity of neurons in the vestibular nuclei was observed only from P15 onwards. To confirm those results, we performed two series of experiments on in vitro preparations of newborn opossums, using stimulation of the vestibular apparatus and physiological recording of the induced motor responses Thus, vertical head tilts did not induce motor response at any of the ages studied (P4-P12). In contrast, mechanical pressure applied on the labyrinth to stimulate the vestibular organs induced motor responses at all ages studied (P1-P9). Our results suggest that the vestibular system’s function is limited by the maturity of its sensory organs and that it can’t influence motor activity in physiological condition before the end of the 2nd postnatal week, even if functional pathways from the labyrinth to the spinal cord seem to be already in place at birth.

Alcohol, recently named the most dangerous drug in the world, contributes to nearly 40% of violent crimes and fatal traffic accidents, increases risk of roughly 60 different diseases and injuries, and is responsible for 2.5 million deaths each year worldwide. Despite these staggering figures, treatments remain ineffective and riddled with adverse side effects, making successful use of even the most effective treatments unlikely. Moreover, many of the treatments, and the supporting research, have focused only on male subjects, despite sex differences in various alcohol-related behaviors. Human alcohol use is frequently accompanied by nicotine use, and vice versa, suggesting a common mechanism of the two drugs. In fact, alcohol may act through the same family of receptors as nicotine, the nicotinic acetylcholine receptors (nAChRs), eliciting similar activation of the reward pathway as nicotine and other drugs of abuse. Studies have shown that nAChRs containing the α4 and/or α6 subunits are involved in nicotine-induced activation of the reward pathway, leading to the hypothesis that these same receptor subtypes may be important for alcohol effects in the brain as well. Using male and female genetic mouse models and various behavioral assays, we have shown not only that these α4 and/or α6-containing nAChRs are involved in alcohol- related behaviors and activation of the reward pathway, but also show sex differences in this involvement. Uncovering the mechanism of alcohol in the brain, in males as well as in females, is an important step in developing targeted treatments for alcohol abuse.