Le RFRP est une neuropeptide impliqué dans la régulation de l’axe reproducteur, mais ses effets varient en fonction du sexe et des espèces. Le but de cette étude était de décrire en détails l’organisation du système RFRP et de caractériser son rôle dans le contrôle circadien et saisonnier de l’axe reproducteur de hamsters femelles. Les résultats montrent que le système RFRP est régulé par la photopériode et que son niveau d’expression est plus élevé chez les femelles que chez les mâles. Cela se traduit par des actions spécifiques sur l’axe gonadotrope femelle. En effet, L’activité des neurones à RFRP est diminuée au moment du pic pré-ovulatoire de LH et des injections centrales de RFRP-3 dans l’heure qui précède le pic de LH induisent une diminution de l’amplitude de la sécrétion de LH, démontrant une implication du RFRP dans la régulation circadienne du pic pré-ovulatoire de LH. Par ailleurs, des infusions chroniques de RFRP-3 chez des hamsters femelles sexuellement inactifs sont capables de réactiver le fonctionnement de l‘axe reproducteur, ce qui montre que le RFRP a un également un rôle régulateur essentiel dans le contrôle saisonnier de la reproduction. / RFRP neurons regulate the reproductive axis, however, their effects depend on species and sex. Here, we aimed at providing a neuroanatomical description of the RFRP system in the Syrian hamster and at investigating the role of RFRP in the daily and seasonal control of female reproduction. We show that besides being regulated by annual changes in photoperiod, the RFRP system is more strongly expressed in females than in males. In line with this, we unveil that RFRP has multiple roles in regulating female reproduction. RFRP neuronal activity is specifically reduced at the time of the pre-ovulatory LH surge and central RFRP-3 administration prior to the surge decreases LH peak levels, altogether pointing towards a daily down-regulation of the inhibitory RFRP signal necessary for proper generation of the LH surge. Moreover, chronic RFRP-3 infusion in sexually inactive females, with endogenous low RFRP expression, completely reactivates the reproductive axis. Taken together, we demonstrate that RFRP is a key component in the seasonal control of reproduction while at the same time specifically regulating cyclic events controlling reproductive activity in females.

Introdução: o ciclo de sono-vigília é o comportamento rítmico circadiano mais onipresente nos humanos. Ele é estabelecido por um sistema temporizador circadiano endógeno que é regulado pela presença ou ausência de luz no ambiente. O comportamento em relação a dormir e acordar varia entre os indivíduos e essa característica nomeia-se cronotipo. Efeitos negativos à saúde têm sido associados ao cronotipo que apresenta horários para iniciar e terminar o sono mais tarde. A hipótese considerada para explicar esses achados é de que demandas sociais, que não levam em conta essa variabilidade individual, sejam mediadoras dessa relação. Objetivos: avaliar a associação entre cronotipo e saúde mental (bem-estar psicológico e sintomas depressivos) levando-se em conta fatores demográficos (sexo e idade) e as rotinas de escola ou trabalho. Materiais e métodos: estudos transversais aninhados a um estudo epidemiológico em uma amostra de indivíduos do Vale do Taquari, no sul do Brasil. Na primeira avaliação, 6.506 participantes foram avaliados quanto a variáveis demográficas, dados de saúde, sintomas depressivos (Inventário de Depressão de Beck – BDI) e cronotipo (Questionário de Cronotipo de Munique – MCTQ). Na segunda etapa, 1.127 indivíduos entre 18 e 65 anos, selecionados a partir de seu cronotipo foram avaliados através do Índice de bem-estar de 5-itens da Organização Mundial da Saúde (OMS). O ponto médio do sono nos dias de rotinas de trabalho ou escolares foi utilizado como indicador do cronotipo, sendo “atrasado” aquele que tem o ponto médio mais tarde em relação ao início da noite e “avançado”, mais cedo. Resultados: no primeiro artigo, estudou-se a relação entre cronotipo e depressão em uma amostra de estudantes adolescentes. O modelo de regressão que melhor explicou a diferença entre os grupos com diferentes níveis de sintomas de depressão (BDI<10 X BDI!10) incluiu o sexo feminino e o cronotipo atrasado. O segundo artigo demonstrou que a escala de Bem-estar de 5-itens da OMS tem uma estrutura unidimensional, boa validade interna e externa e utilidade como instrumento de triagem para depressão quando comparada ao BDI. Assim, no terceiro artigo, foi avaliada a relação entre cronotipo e bem-estar, em indivíduos entre 18 e 65 anos. O modelo de regressão que incluiu o cronotipo atrasado, maior carga de trabalho, rotinas de trabalho mais cedo no dia e menor exposição à luz do sol, como variáveis preditoras, e piores escores na Escala de Bem-estar, como desfecho, foi significativo para o sexo feminino. Discussão: a presente tese explicitou a importância de considerar os fatores idade e sexo na expressão do cronotipo e na relação deste com saúde mental. Corroborou com a hipótese de que as demandas sociais mediam a relação entre cronotipo e os desfechos estudados. A expressão do cronotipo nos dias de rotinas escolares ou de trabalho foi identificada como a variável que estabeleceu a mais forte relação com piores escores de bemestar e com mais sintomas de depressão. Por fim, reforçou a necessidade de revermos as rotinas de trabalho e escolares que, ao não considerarem as diferenças fisiológicas individuais, têm-se associado, de forma consistente, a conseqüências negativas à saúde. / Introduction: the sleep-wake cycle is the most ubiquitous human circadian rhythmic behavior. It is established by an endogenous circadian timing system that is regulated by the presence or absence of light in the environment. Sleep and wake behavior varies among individuals and this feature has been termed chronotype. Negative health effects have been associated with the chronotype that presents later start and end sleep times. A hypothesis to explain these findings is that social demands, which do not take into account individual variability, are mediators of this relationship. Objectives: to evaluate the association between chronotype and mental health (psychological well-being and depressive symptoms) taking into account demographic factors (age and sex) and the routines of school or work. Materials and methods: the studies included here are cross-sectional nested to an epidemiological study in a sample of individuals from “Vale do Taquari”, in southern Brazil. In the first evaluation, 6,506 participants were assessed for demographic variables, health data, depressive symptoms (Beck Depression Inventory - BDI) and chronotype (Munich Chronotype Questionnaire - MCTQ). In the second stage, 1,127 individuals between 18 and 65 years, selected based on their chronotype, were evaluated through the Well-being 5 items Index from the World Health Organization (WHO). The midpoint of sleep on working or school days was used as an indicator of chronotype, and considered "delayed" or “late” those who have later midpoints in relation to environmental night and "advanced" or “early”, earlier. Results: in the first article, we studied the relationship between chronotype and depression in a sample of adolescent students. The regression model that best explained the difference between groups with different levels of depression symptoms (BDI<10 X BDI!10) included female sex and late chronotype. The second article demonstrated that the Well-being index has a unidimensional structure, good internal and external validities and might be usefulness as a screening tool for depression when compared to the BDI. Thus, in the third article, we evaluated the relationship between chronotype and well-being in individuals between 18 and 65 years. The regression model that included late chronotype, increased workload, earlier working routines in the day and less exposure to sunlight, as predictor variables, and worse scores on the well-being index, as the outcome was significant for females. Discussion: the present thesis content highlighted the importance of considering age and sex as factors influencing the expression of chronotype and the relationship with mental health outcomes. It corroborated the hypothesis that social demands mediate the relationship between chronotype and the studied outcomes. The expression of chronotype during the days of work or school routines was identified as the variable that established the strongest relationship with worse well-being scores and more depression symptoms. Finally, it reinforced the need to reconsider work and school routines that, by not taking into acount individual physiological differences, have been associated consistently with negative health consequences.

O uso de répteis como modelos experimentais é limitado, principalmente devido às particularidades fisiológicas da classe, como as oscilações diárias e sazonais em seu comportamento. O objetivo deste estudo foi avaliar a atividade locomotora e nociceptiva de teiús (Salvator merianae) e iguanas-verdes (Iguana iguana) submetidos a testes comportamentais, ao longo do dia e do ano. Foram utilizados seis exemplares de cada espécie, mantidos em sala com temperatura ambiental (24 a 30°C) e fotoperíodo (12h:12h) controlados. Esses foram avaliados ao longo do dia (0:00h, 6:00h, 12:00h, 18:00h) e ao longo do ano (análise mensal). A análise locomotora foi realizada através do teste de campo aberto (teiús e iguanas), no qual o animal foi colocado no centro de uma arena circular por 15 minutos, e recebeu um ponto por cada ultrapassagem pelas subdivisões da mesma; e pelo teste de natação forçada (iguanas), no qual o tempo de atividade foi mensurado em piscina sem saída por 2 minutos. A resposta nociceptiva foi avaliada por meio de mensuração do período de latência do membro em resposta a estímulo nocivo térmico (25 segundos; 245 ± 7 mW/cm2) na superfície plantar do membro do animal. Não foram detectadas oscilações ao longo do ano no teste de campo aberto em nenhuma das espécies. Ao longo do dia, oscilações foram detectadas de Fevereiro a Dezembro em teiús; e em Abril, Maio, Junho e Outubro em iguanas. O tempo de atividade das iguanas foi menor em Janeiro e às 0:00h. Maiores latências de retirada do membro foram observadas nos meses de Maio e Agosto e às 6:00h em ambas espécies. Conclue-se que teiús e iguanas-verdes em ambiente controlado apresentam oscilações significativas em comportamento observado em teste de campo aberto, teste de natação forçada (somente iguanas) e teste plantar, que aparentemente não seguem padrões anuais claros, sendo provavelmente influenciado por fatores múltiplos ainda não compreendidos para as espécies. / The use of reptiles as experimental models is limited due to their physiological particularities, such as daily and annual fluctuations in behavior. The aim of this study was to evaluate locomotor and nociceptive activities of tegus (Salvator merianae) and green iguanas (Iguana iguana) throughout the day and the year, when undergoing behavioral tests. Six animals from each species, kept under controlled room temperature (24 to 30°C) and photoperiod (12h:12h), were used. They were evaluated throughout the day (0:00h, 6:00h, 12:00h and 18:00) and the year (monthly). Locomotor activity was measured by the open field test, in which the animal was placed in the center of a round arena for 15 minutes and the number of crossings through the subdivisions of the arena was counted, and by the forced swim test (iguanas), in which the activity period was timed after animals were placed in a pool with no scape for 2 minutes. Nociceptive activity was measured as the latency to limb withdrawal reflex in response to a noxious thermal stimulus (25 seconds, 245 ± 7 mW/cm2) in the plantar surface of the animal\'s limb. No differences were detected in locomotor activity in the open field test throughout the year in both species. Throughout the day, fluctuations were detected from February to December in tegus, and in April, May, June and October in iguanas. Activity period in iguanas were shorter in January and at 0:00h. Longer latencies to withdrawal reflex were detected in May and August and at 6:00h in both species. In conclusion, tegus and green iguanas kept in controlled environment have fluctuations in behavior presented in the open field test, the forced swim (only iguanas) test and the plantar test, which apparently do not follow a clear seasonal pattern and are probably influenced by multiple factors that are still unknown for both species.

The paper summarizes the basic light-technical parameters, the principles of visual and non-visual photoreceptions and the effects of light on the organism. Several chapters focus on the mechanism by which light affects hormone levels and the circadian rhytm of the organism. In relation to the lighting system, the impact of electromagnetic radiation, associated with the controls, on the body is also considered. Briefly described are systems based on smart LED light sources or smart switches. The result of the thesis is to choose the solution that best suits the requirements of the contracting authority.

No description available.

Sleep is an essential part of life, and obtaining quality sleep is important for various areas of functioning. Behaviors to promote sleep include physical activity, managing stress, reducing anxiety symptoms, maintaining a consistent sleep schedule, and obtaining bright light exposure. Many of these behaviors overlap with benefits observed from pet ownership (PO). The present study aimed to examine the relation between PO and sleep as well as moderators and mediators of this relation. Four research questions were examined: 1) Is PO significantly related to sleep? 2) Does gender moderate the relation between PO and sleep? 3) Do sleep-promoting behaviors (i.e., physical activity, perceived stress, anxiety symptoms, bright light exposure, sleep-wake variability) mediate the relation between PO and sleep? 4) Do the mediating effects of the sleep-promoting behaviors on the relation between PO and sleep depend on the regularity of walking? Participants (N = 1,250; 80.8% White; 50.5% men) residing in the United States reported on their sleep, physical activity, perceived stress, anxiety symptoms, and light exposure. Participants were 25.5% non-pet owners (NPO), 24.1% cat-only owners (CO), 25.7% dog-only owners (DO), and 24.7% owned dogs and cats (DCO). Data analyses included ANCOVA, Moderation, Parallel Mediation, and Conditional Process Modeling. Key findings included that PO was significantly related to sleep, with NPO sleeping worse than PO (CO/DO/DCO combined) and DCO reporting the best sleep of all four PO groups. The relation between PO and sleep did not significantly differ for men and women. The relation was significantly mediated by anxiety symptoms, perceived stress, light exposure, and sleep-wake variability depending on the groups compared and scoring methods used. Anxiety symptoms and perceived stress were the most robust mediators of the relation between PO and sleep. Walking regularity did not change the mediating effects between PO and sleep. This study is one of the first to examine daytime mechanisms of the relation between PO and sleep. The findings provide a foundation for future research examining how the integration of PO and sleep-promoting behaviors can improve adherence to sleep health recommendations, thus improving owners’ sleep.

Le sommeil est un comportement qui occupe un tiers de notre vie. L'horaire, la durée, et la qualité du sommeil sont contrôlés par deux processus principaux : la régulation homéostatique du sommeil et l’horloge qui synchronise les rythmes circadiens internes. EPHA4 est une molécule d'adhésion cellulaire qui régule la neurotransmission et qui est exprimée dans des régions cérébrales impliquées dans la régulation circadienne et du sommeil. De manière intéressante, le gène EphA4 contient des éléments régulateurs des facteurs de transcription circadiens et les souris Clock mutantes voient leur expression d’EphA4 modifiée. De plus, les souris EphA4 knockout (KO) ont des rythmes circadiens d’activité locomotrice anormaux, moins de sommeil paradoxal dans la période de lumière, et une distribution des oscillations cérébrales du sommeil modifiée sur un cycle de 24 heures. Par conséquent, et étant donné que EPHA4 est crucial pour le neurodéveloppement, il convient d’explorer si les phénotypes du sommeil/circadiens observés chez les souris EphA4 KO proviennent d'effets sur le développement ou des rôles d'EPHA4 dans la fonction neuronale adulte. Par ailleurs, les mécanismes de régulation transcriptionnelle d'EphA4 sont encore méconnus. Dans cette thèse, nous avons émis les hypothèses que i) l'expression du gène EphA4 ou de leurs ligands Éphrines (Efns) est régulée de manière circadienne ; et ii) que le modulateur de l’activité d’EPHA4 rhynchophylline (RHY) modifie le sommeil chez les souris adultes d'une manière qui ressemble au phénotype EphA4 KO. L'étude I montre que les facteurs de transcription de l’horloge (CLOCK/NPAS2 et BMAL1) activent la transcription via les éléments de réponse à l'ADN «boîtes E» trouvées dans les promoteurs putatifs d'EphA4, EfnB2 et EfnA3 in vitro. Cependant, les protéines EPHA4 et EFNB2 n’ont pas montré une oscillation circadienne dans le cortex préfrontal et les noyaux suprachiasmatiques (horloge principale) de souris. Dans le projet II, l'effet de RHY sur le sommeil a été étudié chez des souris mâles et femelles avec des enregistrements electroencéphalographiques. Nos données ont démontré que RHY prolonge le sommeil à onde lente, mais les effets sur le sommeil paradoxal dépendent de l’heure d’injection. RHY modifie aussi les oscillations cérébrales pendant l’éveil et le sommeil. Tous ces effets sont notablement plus marqués chez les femelles, ce qui souligne l’importance d’étudier les deux sexes lors des essais pharmacologiques. La transcriptomique spatiale cérébrale révèle que RHY modifie des transcrits liés à des réponses d’inflammation dans tout le cerveau, mais qu'elle affecte l'expression génique des neuropeptides associés à la régulation du sommeil et hypophysaires particulièrement dans l’hypothalamus. En outre, RHY affecte l'expression des gènes de la transcription/traduction de manière diffèrent selon l’heure d’injection. La première publication met en évidence que la régulation transcriptionnelle d’EphA4 et des Efns pourraient expliquer quelques-uns des phénotypes observés chez les souris KO. La deuxième publication démontre que RHY induit le sommeil chez la souris et souligne l’importance de caractériser des mécanismes inexplorés sous-jacents aux composés naturels. Décrire la régulation moléculaire du sommeil peut apporter des éclairages utiles pour la chronopharmacologie. / Sleep is a behavior which occupies a third of our lifetime. The schedule, the duration and the quality of sleep are controlled by two main processes: the homeostatic sleep regulation and the clock that synchronizes the internal circadian rhythm. EPHA4 is a cell adhesion molecule regulating neurotransmission and is expressed in brain centers regulating sleep and circadian rhythms. Interestingly, the EphA4 gene contains regulatory elements for circadian transcription factors, and Clock mutant mice have altered EphA4 expression. Moreover, EphA4 knockout mice (KO) have abnormal circadian rhythms of locomotor activity, less paradoxical sleep in the light period and altered sleep brain oscillations across the 24 hours. Given that EPHA4 is crucial for development, it should be investigated whether the sleep/circadian phenotypes observed in EphA4 KO originate from developmental effects or from roles of EPHA4 in adult neuronal function. Moreover, very little is known about the transcriptional regulation of EPHA4. Thus, the hypotheses of this thesis were that i) the gene expression of EphA4 or that of its ligands Ephrins (Efns) is regulated in a circadian manner; and ii) that the modulator of EPHA4 activity rhynchophylline (RHY) modifies sleep in adult mice in manners that resemble the EphA4 KO phenotype. Project I demonstrates that the clock transcription factors (CLOCK/NPAS2 et BMAL1) activate transcription via the DNA regulatory elements “E-boxes” found in the putative promoters of EphA4, EfnB2 and EfnA3 in vitro. Nevertheless, EPHA4 and EFNB2 proteins did not show a circadian oscillation in the mouse prefrontal cortex and suprachiasmatic nuclei (master clock). In project II, the effect of RHY on sleep was studied in male and female mice with electroencephalographic recordings. RHY extends slow wave sleep and effects on paradoxical sleep depended on the time-of-injection. RHY also modified the brain oscillations during wakefulness and sleep. Importantly, all these effects were larger in females, which highlights the need to consider both sexes in pharmacological studies. Brain spatial transcriptomics reveals that RHY modifies transcripts linked to inflammatory responses throughout the brain, while it affects transcripts linked to sleep regulation and pituitary responses particularly in the hypothalamus. Moreover, RHY affected the expression of genes for transcription/translation differently depending on the time of injection. The first publication underscores that the transcriptional regulation of EphA4 and Efns may underly some of the phenotypes observed in the KO mice. The second publication demonstrates that RHY induces sleep in mice, that it modifies brain activity associated to cognitive processes and highlights the importance of characterizing unexplored mechanisms of natural compounds. Describing the molecular regulation of sleep may provide useful insights for chronopharmacology.

No description available.

The study of cis-regulatory elements (CREs) will allow for increased understanding of regulation and lead to insight regarding the mechanisms governing growth, development, health, and disease. The aim of this study was to characterize the de novo in silico predictions of Arabidopsis CREs. Eight synthetic and 30 native promoter-constructs containing an eGFP/GUS reporter protein were generated for cold, genotoxic, heat, osmotic, and salt stress; the circadian clock; ABA signaling; root and epidermis tissue. Constructs were stably transformed into A. thaliana Col-0 and the effects of the CREs were evaluated by in planta stress or tissue assays using GUS expression levels. Results reveal a novel genotoxic element that specifically directs GUS expression in rosette leaves during genotoxic stress. Results also look promising for novel epidermis and root-specific elements. Results of these assays validate the de novo prediction pipeline's ability to identify novel and known CREs related to abiotic stress.

The study of cis-regulatory elements (CREs) will allow for increased understanding of regulation and lead to insight regarding the mechanisms governing growth, development, health, and disease. The aim of this study was to characterize the de novo in silico predictions of Arabidopsis CREs. Eight synthetic and 30 native promoter-constructs containing an eGFP/GUS reporter protein were generated for cold, genotoxic, heat, osmotic, and salt stress; the circadian clock; ABA signaling; root and epidermis tissue. Constructs were stably transformed into A. thaliana Col-0 and the effects of the CREs were evaluated by in planta stress or tissue assays using GUS expression levels. Results reveal a novel genotoxic element that specifically directs GUS expression in rosette leaves during genotoxic stress. Results also look promising for novel epidermis and root-specific elements. Results of these assays validate the de novo prediction pipeline's ability to identify novel and known CREs related to abiotic stress.