Background: Adipose-derived stem/stromal cells (ASCs) isolated from the stromal vascular fraction are a source of mesenchymal stem cells that have been shown to be beneficial in many regenerative medicine applications. ASCs are an attractive source of stem cells in particular, due to their lack of immunogenicity. This study examines differences between mitochondrial bioenergetic profiles of ASCs isolated from adipose tissue of five peri-organ regions: pericardial, thymic, knee, shoulder, and abdomen. Results: Flow cytometry showed that the majority of each ASC population isolated from the adipose tissue of 12 donors, with an n = 3 for each tissue type, were positive for MSC markers CD90, CD73, and CD105, and negative for hematopoietic markers CD34, CD11B, CD19, and CD45. Bioenergetic profiles were obtained for ASCs with an n = 4 for each tissue type and graphed together for comparison. Mitochondrial stress tests provided the following measurements: basal respiration rate (measured as oxygen consumption rate [pmol O-2/min], ATP production, proton leak, maximal respiration, respiratory control ratio, coupling efficiency, and non-mitochondrial respiration. Glycolytic stress tests provided the following measurements: basal glycolysis rate (measured as extracellular acidification rate [mpH/min]), glycolytic capacity, glycolytic reserve, and non-glycolytic acidification. Conclusions: The main goal of this manuscript was to provide baseline reference values for future experiments and to compare bioenergetic potentials of ASCs isolated from adipose tissue harvested from different anatomical locations. Through an investigation of mitochondrial respiration and glycolysis, it was demonstrated that bioenergetic profiles do not significantly differ by region due to depot-dependent and donor-dependent variability. Thus, although the physiological function, microenvironment and anatomical harvest site may directly affect the characteristics of ASCs isolated from different organ regions, the ultimate utility of ASCs remains independent of the anatomical harvest site.

A cianobactéria fotossintetizante Arthrospira platensis é conhecida por apresentar em sua biomassa altos teores protéicos (50-70%), presença do ácido graxo essencial γ-linolênico e diversas outras substâncias importantes para a alimentação humana e animal. Esses micro-organismos são capazes de converter o CO2 em biomassa de grande potencial na área de alimentos. Durante a fermentação alcoólica, a produção de CO2 é da mesma ordem de grandeza da produção de etanol e, considerando a crescente demanda interna e externa por esse combustível, seria importante que houvesse um processo que fixasse esse CO2, transformando-o em um produto que poderia ser útil para a nossa população. Adicionalmente, o uso de uma fonte de nitrogênio de baixo custo (uréia) em reatores tubulares contribuiria para a redução do custo de produção da A. platensis. O objetivo desse trabalho foi avaliar os parâmetros cinéticos e bioenergéticos, bem como a composição centesimal da A. platensis cultivadas em biorreator tubular, alimentados com CO2 proveniente de fermentação alcoólica ou com utilização de CO2 puro, para o controle do pH, sob diferentes intensidades luminosas (I) e fontes de nitrogênio (N) adicionadas por meio de processo descontínuo alimentado. Os resultados mostraram que maiores valores de I proporcionaram maiores valores de concentração celular máxima (Xm) e produtividade em células (Px), mas não influenciaram nos valores do fator de conversão de nitrogênio em células (YX/N). As diferentes fontes de CO2 não influenciaram nos valores de Xm, Px, YX/N. O uso da uréia aumentou os valores de YX/N em relação aos cultivos com NO3-. Na composição centesimal, pode-se observar que I influenciou nos teores de clorofila, proteínas e lipídios, mas não influenciou nos teores de cinzas e carboidratos na biomassa final. Em relação aos parâmetros bioenergéticos dos cultivos com CO2 puro, observou-se que os maiores valores de dissipação de energia de Gibbs foram obtidos em tempos mais curtos a 120-240 µmol de fótons m-2 s-1, independentemente do N selecionado, enquanto que o número de moles de fótons absorvidos pelas células para produzir um C-mol de biomassa foi maior nas culturas com NO3-, independentemente do I. As frações da energia direcionada para a síntese de ATP e fixada pela célula foram superiores em culturas com uréia quando comparadas com as culturas com NO3-, que se revelou uma fonte de nitrogênio capaz de sustentar o crescimento energicamente da A. platensis. / Photosynthetic cyanobacterium A. platensis contains in its biomass high protein content (50-70%), γ-linolenic acid and many other substances important for health human. These microorganisms are capable of converting CO2 into biomass of great potential in the food industry. During the alcoholic fermentation, the production of CO2 has the same magnitude of the production of ethanol. Considering the increasingly global demand for this fuel, a process to fix this CO2 is of utmost importance. Furthermore, the use of low cost nitrogen source (urea) in tubular reactors would contribute to reducing the production cost of A. platensis. Therefore, the purpose of this work was to evaluate the kinetic and bioenergetics parameters, as well as the chemical composition of biomass obtained in A. platensis cultures in tubular bioreactor using CO2 from alcoholic fermentation or pure CO2 to control the pH under different light intensity (I) and nitrogen sources (N). The results showed that higher I induced higher maximum cell concentration (Xm) and cell productivity (Px) values, but it did not exert any influence on the nitrogen-cell conversion factor (YX/N). Urea increased the YX/N values compared to use of NO3-. In the centesimal composition of biomass, it can be observed that I influenced the chlorophyll, protein, and lipid contents, but not influenced the carbohydrate and ash contents. For bioenergetics parameters, it was observed that the highest Gibbs energy dissipation values for cell growth and maintenance were obtained in shorter time at 120-240 mol photons m-2 s-1 in both nitrogen sources, while the moles of photons absorbed by the system to produce one C-mol biomass was higher in cultures with NO3-. The highest values of the molar production of O2 and consumption of H+ were obtained at the highest I values, using NO3-. The estimated percentages of the energy absorbed by the cell showed that, compared with nitrate, the use of urea as nitrogen source allowed the system to address higher fractions to ATP production and light fixation by the photosynthetic apparatus, as well as a lower fraction released as heat. Thanks to this better bioenergetic situation, urea appears to be a quite promising low-cost, alternative nitrogen source for A. platensis cultures in photobioreactors.

A cianobactéria fotossintetizante Arthrospira platensis é conhecida por apresentar em sua biomassa altos teores protéicos (50-70%), presença do ácido graxo essencial γ-linolênico e diversas outras substâncias importantes para a alimentação humana e animal. Esses micro-organismos são capazes de converter o CO2 em biomassa de grande potencial na área de alimentos. Durante a fermentação alcoólica, a produção de CO2 é da mesma ordem de grandeza da produção de etanol e, considerando a crescente demanda interna e externa por esse combustível, seria importante que houvesse um processo que fixasse esse CO2, transformando-o em um produto que poderia ser útil para a nossa população. Adicionalmente, o uso de uma fonte de nitrogênio de baixo custo (uréia) em reatores tubulares contribuiria para a redução do custo de produção da A. platensis. O objetivo desse trabalho foi avaliar os parâmetros cinéticos e bioenergéticos, bem como a composição centesimal da A. platensis cultivadas em biorreator tubular, alimentados com CO2 proveniente de fermentação alcoólica ou com utilização de CO2 puro, para o controle do pH, sob diferentes intensidades luminosas (I) e fontes de nitrogênio (N) adicionadas por meio de processo descontínuo alimentado. Os resultados mostraram que maiores valores de I proporcionaram maiores valores de concentração celular máxima (Xm) e produtividade em células (Px), mas não influenciaram nos valores do fator de conversão de nitrogênio em células (YX/N). As diferentes fontes de CO2 não influenciaram nos valores de Xm, Px, YX/N. O uso da uréia aumentou os valores de YX/N em relação aos cultivos com NO3-. Na composição centesimal, pode-se observar que I influenciou nos teores de clorofila, proteínas e lipídios, mas não influenciou nos teores de cinzas e carboidratos na biomassa final. Em relação aos parâmetros bioenergéticos dos cultivos com CO2 puro, observou-se que os maiores valores de dissipação de energia de Gibbs foram obtidos em tempos mais curtos a 120-240 µmol de fótons m-2 s-1, independentemente do N selecionado, enquanto que o número de moles de fótons absorvidos pelas células para produzir um C-mol de biomassa foi maior nas culturas com NO3-, independentemente do I. As frações da energia direcionada para a síntese de ATP e fixada pela célula foram superiores em culturas com uréia quando comparadas com as culturas com NO3-, que se revelou uma fonte de nitrogênio capaz de sustentar o crescimento energicamente da A. platensis. / Photosynthetic cyanobacterium A. platensis contains in its biomass high protein content (50-70%), γ-linolenic acid and many other substances important for health human. These microorganisms are capable of converting CO2 into biomass of great potential in the food industry. During the alcoholic fermentation, the production of CO2 has the same magnitude of the production of ethanol. Considering the increasingly global demand for this fuel, a process to fix this CO2 is of utmost importance. Furthermore, the use of low cost nitrogen source (urea) in tubular reactors would contribute to reducing the production cost of A. platensis. Therefore, the purpose of this work was to evaluate the kinetic and bioenergetics parameters, as well as the chemical composition of biomass obtained in A. platensis cultures in tubular bioreactor using CO2 from alcoholic fermentation or pure CO2 to control the pH under different light intensity (I) and nitrogen sources (N). The results showed that higher I induced higher maximum cell concentration (Xm) and cell productivity (Px) values, but it did not exert any influence on the nitrogen-cell conversion factor (YX/N). Urea increased the YX/N values compared to use of NO3-. In the centesimal composition of biomass, it can be observed that I influenced the chlorophyll, protein, and lipid contents, but not influenced the carbohydrate and ash contents. For bioenergetics parameters, it was observed that the highest Gibbs energy dissipation values for cell growth and maintenance were obtained in shorter time at 120-240 mol photons m-2 s-1 in both nitrogen sources, while the moles of photons absorbed by the system to produce one C-mol biomass was higher in cultures with NO3-. The highest values of the molar production of O2 and consumption of H+ were obtained at the highest I values, using NO3-. The estimated percentages of the energy absorbed by the cell showed that, compared with nitrate, the use of urea as nitrogen source allowed the system to address higher fractions to ATP production and light fixation by the photosynthetic apparatus, as well as a lower fraction released as heat. Thanks to this better bioenergetic situation, urea appears to be a quite promising low-cost, alternative nitrogen source for A. platensis cultures in photobioreactors.

Complexity science has come into the limelight in recent years as the scientific community begins to grapple with higher-order natural phenomena that cannot be fully explained via the behaviour of components at lower levels of organization. Network modeling and analysis, being a powerful tool that can capture the interconnections that embody complex behaviour, has therefore been at the forefront of complexity science. In ecology, the network paradigm is relatively young and there remain limitations in many ecological network studies, such as modeling only one type of species interaction at a time, lack of realistic network structure, or non-inclusion of community dynamics and environmental stochasticity. I introduce bioenergetic network models that bring together for the first time many of the fundamental structures and mechanisms of species interactions present in real ecological communities. I then use these models to address some outstanding questions that are relevant to understanding ecological networks at the systems level rather than at the level of subsets of interactions. Firstly, I find that realistic red-shifted environmental noise, and synchrony of species responses to noise, are associated with increased variability in ecosystem properties, with implications for predictive ecological modeling which usually assumes white noise. Next, I look at simultaneous species extinction and invasion, finding that as their individual impacts increase, their combined impact becomes decreasingly additive. In addition, the greater the impact of extinction or invasion, the lesser their reversibility via reintroduction or eradication of the species in question. For modifications of pairwise species interactions by third-party species, a phenomenon that has so far been studied one interaction at a time, I find that the many interaction modifications that occur concurrently in a community can collectively have systematic effects on total biomass and species evenness. Finally, examining a higher level of organization in the form of compartmentalized networks, I find that the relationship between intercompartment connectivity and the impacts of species decline depends considerably on network topology and whether the consumer-resource functional response is prey- or ratio-dependent. Overall, the results vary considerably across model communities with different parameterizations, underscoring the contingency and context dependence of nature that scientists and policy makers alike should no longer ignore. This work hopes to contribute to a growing multidisciplinary understanding, appreciation and management of complex systems that is fundamentally transforming the modern world and giving us insights on how to live more harmoniously within our environment.

Animal behaviour is a state variable of the individual that deserves special attention given its determinant role in eco-evolutionary processes (Wolf et al. 2007 in Nature). The decomposition of the behavioural variation in between- and within-individual variability has revealed the existence of consistent between-individual differences referred to as personality or behavioural types (Dall et al. 2004 in Ecology Letters). Five axes of personality are usually recognized (exploration, aggressiveness, activity, sociability and boldness), and individual specificities along them tend to be correlated leading to what is known as behavioural syndromes. Recently, these patterns of covariation have been enlarged to accommodate movement behaviour within a personality-dependent spatial ecology theory (Spiegel et al. 2017 in Ecology Letters). Most animals tend to forage, reproduce and develop any activity within specific bounded space, which leads to the formation of home range (HR) areas (i.e., HR behaviour, Börger et al. 2008 in Ecology Letters). The increasing development of animal tracking technology is providing a huge amount of movement data revealing that HR behaviour is widespread among taxa and shows a large consistent variability, both at within- and between-individual level, which allows to define the existence of well-contrasted spatial behavioural types (SBTs). SBTs, as other personality traits, play an important role in selective processes as those impelled by harvesting activities. The Pace-of-Life-Syndrome (POLS) theory (Réale et al. 2010 in Philos. Trans. R. Soc. B Biol. Sci), hypothesises on how personality traits are expected to be correlated with life history (LH) traits along the fast-slow continuum (Stearns 1992 in Oxford Univ. Press) in the broadest sense. Accordingly, patterns of covariation between specific SBTs, physiology-related features and LHs would be expected to exist whenever they maximize the animal performance in a given environment. However, the way in which behavioural variation at the within-species level is translated to the wide range of LH traits remains a fundamental yet unresolved question, mainly due to the lack of a proper theoretical framework (Mathot & Frankenhuis, March 2018 in Behavioral Ecology and Sociobiology). Thus, unrevealing the mechanisms behind is certainly scientifically very exciting but also socially relevant. In such a context, this PhD thesis aimed to address from conceptual, empirical and theoretical perspectives cornerstone questions in behavioural ecology: what are the feasible mechanisms underpinning the establishment of HR areas and within-species variation, what are their consequences for animal functioning and performance (i.e., in. LH traits) at the individual and eco-evolutionary levels, or what are the implications for the assessment and conservation of wildlife of the existence of SBTs. The PhD thesis focusses in a fish heavily exploited by recreational fishers but it aims to provide general reasoning applicable to a wide range of wild animals. First, the PhD thesis proposes a mechanistic theory of personality-dependent movement behaviour based on dynamic energy budget models (i.e., a behavioural-bioenergetics theoretical model). Second, integrated in the field of animal personality (i.e., decomposition of behavioural variability into within- and between-individual’s components), it addresses empirically the study of behavioural variability in the main axis of personality for a marine fish species and looked for evidences of whether personality-mediated differences in energy acquisition may exist. Aiming to support empirically the possible connections between personality traits and space-use behaviour, the thesis provides some insights on the application of a novel-tracking algorithm to analyse the movement of individual fish submitted to different experimental conditions. Third, it provides two examples of how applying HR-related theoretical concepts may improve the management of natural resources: attending the properties of HR may facilitate the assessment of wildlife using fixed monitoring sampling stations, and considering SBTs may influence the assessment of the status of wild fish stocks. Finally, the adaptive value of the proposed behavioural-bioenergetics theory is explored by means of dynamic optimization to understand the eco-evolutionary consequences related with HR variability. In summary, this PhD thesis makes an important contribution to behavioural ecology by developing a unifying theory to test the generality and adaptive value of POLS based on dynamic energy budgets. This behavioural-bioenergetics model connects (1) personality traits (2) HR behaviour, (3) physiology and (4) LH traits through an interwoven of mass/energy fluxes, within which they interact and feedback with the ecological context. Overall, from an eco-evolutionary perspective, the proposed framework constitutes a powerful tool for exploring the ecological role of HR behaviour and predicting what combination of behavioural traits would be evolutionally favoured in a given ecological context. Moving forward to including managerial scenarios, this unifying theory provides scientifically founded knowledge that would promote to improve natural resource management by attending the behavioural component of animal populations.

L’objet de recherche de ce mémoire est la résilience vue à travers le prisme d’une démarche autobiographique dans un contexte de recherche-formation. Le concept de résilience pouvant être sur ou sous-estimé par divers chercheurs, l’auteure démontre dans l’analyse de son récit de vie, le fait d’une résilience ‘’ordinaire’’ et tout à fait réelle en opposition à une résilience ‘’hors de l’ordinaire’’. L’auteure aborde la notion de résilience à partir de différentes perspectives. Toutefois, elle privilégie l’approche des neurosciences qui démontre, par le biais de l’imagerie cérébrale, le remaniement du cerveau lors d’interactions. Or, pour bien des auteurs dont Boris Cyrulnik et Allan N. Schore, la résilience prend racine suite à une expérience d’attachement, la résilience ne se construisant pas seule. Le parcours autobiographique de l’auteure est bien imprégné du processus thérapeutique d’analyse bioénergétique dans lequel elle s’est engagée. / The research object of this paper is resilience as seen through the prism of an autobiographical approach within a context of research training. The concept of resilience being possibly either over-or under-estimated by various researchers, the author through analysis of her life story, relates the experience of an “ordinary” though very real resilience, this in opposition to an “out of ordinary” one. The author approaches the notion of resilience from various perspectives. However, she privileges the neurosciences approach that shows through brain imaging, the realignment of the brain during interactions. Yet, for many authors including Boris Cyrulnik and Allan N. Schore, resilience takes root following an attachment experience, as resilience cannot be built alone. The author’s therapeutic process of bioenergetic analysis is reflected in her autobiographical journey.

L’objet de recherche de ce mémoire est la résilience vue à travers le prisme d’une démarche autobiographique dans un contexte de recherche-formation. Le concept de résilience pouvant être sur ou sous-estimé par divers chercheurs, l’auteure démontre dans l’analyse de son récit de vie, le fait d’une résilience ‘’ordinaire’’ et tout à fait réelle en opposition à une résilience ‘’hors de l’ordinaire’’. L’auteure aborde la notion de résilience à partir de différentes perspectives. Toutefois, elle privilégie l’approche des neurosciences qui démontre, par le biais de l’imagerie cérébrale, le remaniement du cerveau lors d’interactions. Or, pour bien des auteurs dont Boris Cyrulnik et Allan N. Schore, la résilience prend racine suite à une expérience d’attachement, la résilience ne se construisant pas seule. Le parcours autobiographique de l’auteure est bien imprégné du processus thérapeutique d’analyse bioénergétique dans lequel elle s’est engagée. / The research object of this paper is resilience as seen through the prism of an autobiographical approach within a context of research training. The concept of resilience being possibly either over-or under-estimated by various researchers, the author through analysis of her life story, relates the experience of an “ordinary” though very real resilience, this in opposition to an “out of ordinary” one. The author approaches the notion of resilience from various perspectives. However, she privileges the neurosciences approach that shows through brain imaging, the realignment of the brain during interactions. Yet, for many authors including Boris Cyrulnik and Allan N. Schore, resilience takes root following an attachment experience, as resilience cannot be built alone. The author’s therapeutic process of bioenergetic analysis is reflected in her autobiographical journey.

Le modèle bioénergétique de P.E. di PRAMPERO permet d'expliquer la performance dans les disciplines de locomotion (course à pied, cyclisme, natation, ...) à partir d'une puissance métabolique et d'un indice de la dépense d'énergie par unité de distance parcourue. Néanmoins, pour les épreuves de natation de haute intensité telles que le 100m crawl, le contexte environnemental rend l'estimation de la puissance métabolique d'origine aérobie techniquement difficile. L'objectif de cette thèse est alors de proposer une nouvelle approche des réponses aérobies d'un 100-m nage libre, réalisé dans des conditions les plus proches possible d'une compétition. Le travail expérimental a porté sur des nageurs entraînés. Dans un bassin de 25-m, la procédure propose que les nageurs réalisent une performance sur 100-m nage libre à allure de compétition et trois épreuves (25m, 50m, 75m) réitérant les mêmes allures intermédiaires que celles du 100-m. VO2 est mesuré avant et juste après chaque épreuve, pendant 1min, par rétro-extrapolation. Les valeurs de VO2 mesurées à la fin des épreuves de 25m, 50m, 75m et 100m permettent de reconstruire la cinétique de VO2 d'une épreuve de 100-m. Les résultats contrastent avec les estimations des cinétiques de VO2 publiées précédemment : VO2 augmente plus vite dans la première moitié de l'épreuve (à 50m, VO2 ≈ 94%VO2max), atteint 100 %VO2max au 75ème mètre de l'épreuve puis chute de 7% sur le dernier 25-m. Une estimation de la contribution relative du métabolisme aérobie montre également des valeurs plus importantes que celles publiées jusqu'à ce jour, du fait de l'atteinte précoce de VO2max en cours d'épreuve. / The bioenergetic model proposed by P.E. di PRAMPERO explains performance in most human locomotions (running, cycling, swimming, ...) using indexes of metabolic power and energy cost of locomotion. Nevertheless, for 100-m front crawl events, environmental conditions make the aerobic power measurement difficult. The main purpose of this thesis is therefore to propose a new procedure to estimate aerobic responses during a 100-m front crawl event, performed in competition conditions. Trained swimmers participated to this study. In a 25-m swimming pool, the procedure includes a 100-m front crawl performance in competition conditions, and then, three tests (25-m, 50-m, 75-m) following the pacing strategy of the 100-m event. VO2 is not measured during the tests, but before and just at the end of each test with a breath-by-breath method. Each post-test VO2 (after 25m, 50m, 75m and 100m) allows to reconstruct the VO2 kinetics of the 100-m performance. The results differ from previous studies in that VO2 increases faster in the first half of the race (at 50m, VO2 ± 94%VO2max), reaches VO2max at the 75th meter; then a decrease in VO2 corresponding to 7% of VO2max appears during the last 25m. The estimation of aerobic contribution shows higher values than those previously published, because VO2max is reached very early during the race.

Le récepteur aux cannabinoïdes de type 1 (CB1) est un récepteur couplé aux protéines G, abondamment exprimé dans le cerveau et régulant plusieurs processus physiologiques. Cependant, les mécanismes cellulaires par lesquels les CB1 régulent ces processus n’ont été que peu analysés. Bien que les CB1 localisés dans les membranes plasmiques sont connus pour induire la transduction de signal; une partie de ces récepteurs sont aussi fonctionnels au niveau des mitochondries (mtCB1), où leur stimulation réduit la respiration mitochondriale. L’objectif de cette thèse fut d’évaluer l’impact de l’activation des récepteurs mtCB1 du cerveau sur les effets connus des cannabinoïdes. Afin de distinguer la fonction des mtCB1 de celle des autres populations de récepteurs, nous avons développé des outils basés sur la signalisation induite par les mtCB1. Dans les mitochondries isolées de cerveau, l’activation des protéines Gαi/o, dépendante des mtCB1 diminue l’activité de l’adénylyl cyclase soluble (sAC). L'inhibition locale de l’activité de sAC prévient l’amnésie, la catalepsie et partiellement l’hypolocomotion induite par les cannabinoïdes. De plus, nous avons généré une protéine fonctionnelle mutante CB1 (DN22-CB1) dépourvue des 22 premiers acides aminés des CB1 ainsi que de sa localisation mitochondriale. Contrairement aux CB1, l'activation des DN22-CB1 n’affecte pas l'activité mitochondriale. Enfin, l’expression des DN22-CB1 dans l’hippocampe bloque à la fois la diminution de la transmission synaptique et l’amnésie induites par les cannabinoïdes. Ces travaux démontrent l’implication des mtCB1 dans certains effets des cannabinoïdes et le rôle clé des processus bioénergétiques contrôlant les fonctions cérébrales. / Type-1 cannabinoid receptor CB1 is a G protein-coupled receptor (GPCR), widely expressed in the brain, which regulates numerous physiological processes. However, the cellular mechanisms of CB1-mediated control of these functions are poorly understood. Although CB1 are known to signal at the plasma membrane, a portion of these receptors are also present in mitochondria (mtCB1), where mtCB1 activation decreases mitochondrial activity. The goal of this thesis was to dissect the impact of brain mtCB1 signaling in known behavioral effects induced by cannabinoids. To distinguish the functions of mtCB1 from other receptor pools, we developed tools based on the characterization of the intra-mitochondrial molecular cascade induced by mtCB1 receptors. In isolated brain mitochondria, we found that intra-mitochondrial decrease of soluble-adenylyl cyclase (sAC) activity links mtCB1- dependent activation of Gαi/o proteins to decrease cellular respiration. Local brain inhibition of sAC activity blocks cannabinoid-induced amnesia, catalepsy and contributes to the hypolocomotor effect of cannabinoids. In addition, we generated a functional mutant CB1 protein (DN22-CB1) lacking the first 22 amino acid of CB1 and its mitochondrial localization. Differently from CB1, activation of DN22-CB1 does not affect mitochondrial activity. Hippocampal in vivo expression of DN22-CB1 abolished both cannabinoid-induced impairment of synaptic transmission and amnesia in mice. Together, these studies couple mitochondrial activity to behavioral performances. The involvement of mtCB1 in the effects of cannabinoids on memory and motor control highlights the key role of bioenergetic processes as regulators of brain functions.

The objective of this thesis was to quantify the physiological responses such as O2 uptake (VO2), heart rate (HR) and blood lactate ([LA]) to some types of activities associated with intermittent sports in athletes. Our hypothesis is that the introduction of accelerations and decelerations with or without directional changes results in a significative increase of the oxygen consumption, heart rate and blood lactate. The purpose of the first study was to measure and compare the VO2 and the HR of 6 on-court tennis drills at both high and low displacement speeds. These drills were done with and without striking the ball, over full and half-width court, in attack or in defense mode, using backhand or forehand strokes. Results show that playing an attacking style requires 6.5% more energy than playing a defensive style (p < 0.01) and the backhand stroke required 7% more VO2 at low speed than forehand stroke (p < 0.05) while the additional cost of striking the ball lies between 3.5 and 3.0 mL kg-1 min-1. Finally, while striking the ball, the energy expanded during a shuttle displacement on half-width court is 14% higher than running on full-width court. Studies #2 and #3 focused on different modes of displacement observed in irregular sports. The objective of the second study was to measure and compare VO2, HR and [LA] responses to randomly performed multiple fractioned runs with directional changes (SR) and without directional changes (FR) to those of in-line running (IR) at speeds corresponding to 60, 70 and 80% of the subject’s maximal aerobic speed (MAS). All results show that IR’s VO2 was significantly lower than SR’s and FR’s (p<0.05). SR’s VO2 was greater than FR’s only at speeds corresponding to 80%MAS. On the other hand, HR was similar in SR and FR but significantly higher than IR’s (p<0.05). [LA] varied between 4.2 ± 0.8 and 6.6 ± 0.9 mmol L-1 without significant differences between the 3 displacement modes. Finally, the third study’s objective was to measure and compare VO2 , HR and [LA] responses during directional changes at different angles and at different submaximal running speeds corresponding to 60, 70 and 80% MAS. Subjects randomly performed 4 running protocols 1) a 20-m shuttle running course (180°) (SR), 2) an 8-shaped running course with 90-degree turns every 20 m (90R), 3) a Zigzag running course (ZZR) with multiple close directional changes (~ 5 m) at different angle values of 91.8°, 90° and 38.6°, 4) an In-line run (IR) for comparison purposes. Results show that IR’s was lower (p<0.001) than for 90R’s, SR’s and ZZR’s at all intensities. VO2 obtained at 60 and 70%MAS was 48.7 and 38.1% higher during ZZR when compared to IR while and depending on the intensity, during 90R and SR was between 15.5 and 19.6% higher than during IR. Also, ZZR’s VO2 was 26.1 and 19.5% higher than 90R’s, 26.1 and 15.5% higher than SR’s at 60 and 70%MAS. SR’s and 90R’s VO2 were similar. Changing direction at a 90° angle and at 180° angle seem similar when compared to continuous in-line running. [LA] levels were similar in all modalities. Overall, the studies presented in this thesis allow the quantification of the specific energetic demands of certain types of displacement modes in comparison with conventional forward running. Also, our results confirm that the energy cost varies and increase with the introduction of accelerations and decelerations with and without directional changes. / L’objectif de cette thèse est de quantifier trois réponses physiologiques: la consommation d’oxygène VO2, la fréquence cardiaque (FC) et la lactatémie ([LA]) pour différentes modalités de déplacement observées lors de sports irréguliers (ex: tennis, soccer, basketball et handball) chez des sportifs adultes. Notre hypothèse est que l’accélération et décélération avec et sans changements de direction résultent dans une augmentation significative de la consommation d’oxygène, de la fréquence cardiaque. Le but de la première étude menée dans le cadre de la présente thèse fut de mesurer et comparer le VO2 requis et la réponse de la FC de six types d’activités spécifiques au tennis (Attaque avec frappe de balle, défense avec et sans frappe de balle, coup droit, coup de revers, déplacement latéral) et ce, à des vitesses de déplacement basses et élevées. Ces activités furent exécutées en mode attaque et en mode défense avec utilisation du coup droit et du revers. Les résultats montrent qu’attaquer, nécessite 6.5% plus d’énergie que de défendre (p < 0.01) et que le coût associé au revers est supérieur de 7% à celui du coup droit (p < 0.05) lors des déplacements à vitesses faibles et que la frappe de balle coûte entre 3.5 et 3.0 mL kg-1 min-1. Enfin, frapper la balle et se déplacer en pas chassé sur la moitié de la largeur du court coûte 14% plus d'énergie que de se déplacer sur la largeur totale du court. La deuxième et troisième études présentées portent sur différents modes de déplacement observés dans des sports irréguliers. Ainsi, l’objectif de la seconde étude était de mesurer VO2, FC et [LA] lors des déplacements fractionnés avec (SR) ou sans (FR) changements de direction et de les comparer à ceux de la course continue (IR) à des intensités de 60, 70 et 80% de la vitesse aérobie maximale (VAM) observée en IR. Les résultats montrent que le VO2 requis pour IR fut significativement inférieur à celui de FR et de SR (p<0.05). Le VO2 lors des SR fut supérieur à celui observé lors des FR seulement à 80% VAM. Par contre, la FC fut similaire dans SR et FR mais significativement supérieure à celle de IR (p<0.05). [LA] varia entre 4.2 ± 0.8 et 6.6 ± 0.9 mmol L-1 sans différences significatives entre les 3 modes de déplacement. Enfin, l’objectif de la troisième et dernière étude fut de mesurer la réponse de VO2, de FC et de [LA] lors de déplacements avec changements de direction à différents angles à 60, 70 et 80% de la VAM des sujets. Les modalités de déplacement étaient 1) course navette avec changement de direction à 180° tous les 20 m (SR), 2) course en forme de 8 à angles droits (90R) tous les 20 m, 3) course en zigzag (ZZR) avec plusieurs virages rapprochés (~ 5 m) à différents angles de 91.8°, 90° et 38.6°, 4) course continue (IR) sans virage à des fins de comparaison. Les résultats montrent que le VO2 associé à IR est significativement inférieur à celui observé lors de ZZR, SR et 90R (p<0.001). Le VO2 atteint à 60 et 70% VAM lors de ZZR fut de 48.7 et 38.1% supérieur à celui atteint lors de IR, alors que selon l’intensité, les VO2 lors de 90R et SR furent entre 15.5 et 19.6 % supérieur à celui associé à IR. Toujours à 60 et 70%VAM, le VO2 atteint lors de ZZR fut respectivement de 26.1 et de 19.5% supérieur à celui atteint lors de 90R, et de 26.1 et 15.5% supérieur à celui atteint lors de SR. En ZZR, les sujets furent incapables de compléter la tâche à 80% VAM. En mode SR et 90R et à toutes les intensités, les VO2 mesurés furent similaires. Virer à 90° semble donc aussi exigeant qu’à 180° par rapport à la course continue. Enfin, [LA] était similaire dans toutes modalités. D’une façon générale, les études de cette thèse ont permis de quantifier les exigences énergétiques spécifiques de certaines formes de déplacements par rapport à la course avant conventionnelle. Ceci confirme que les coûts énergétiques varient et augmentent avec les accélérations et décélérations avec et sans changements de direction.