Early-life experience has profound effects on the individual’s neurobiology and behaviour later in life. The rodent animal experimental model maternal separation (MS) was used to study this more in detail. The MS model involves short and prolonged postnatal separations simulating an emotionally safe and stressful environment, respectively. The aims of the thesis were to examine the impact of individual MS on ethanol consumption and on brain dopamine and serotonin systems in adult male rats. Furthermore, the influence of separation conditions on the short- and long-term consequences of MS on several neurotransmitter systems was examined. Rat pups were assigned to either litter-wise MS for 15 or 360 minutes (MS15l or MS360l) or individual MS for 15 or 360 minutes (MS15i or MS360i). Control rats were subjected to conventional animal facility rearing (AFR). Ethanol intake was assessed in a two-bottle free-choice paradigm. Neuropeptides were analyzed with radioimmunoassay, monoamines and metabolites with electrochemical detection and gene expression with qPCR. Using the MSi paradigm, minor effects on voluntary ethanol consumption were observed. However, the monoaminergic responses elicited by ethanol were dependent on the early-life environment. Furthermore, short- and long-term consequences of MS on serotonin, opioid, oxytocin and vasopressin systems were studied. Multiple neurobiological measurements in one and the same rat offered a unique possibility to examine the effects of duration (MS15 versus MS360) and condition (l versus i) of MS. Time-, region-, sex- and transmitter-specific effects were observed. More pronounced differences were seen in serotonin measures and oxytocin in young rats. In adults these differences in basal levels were normalized. Opioid peptides differed in stress-related brain areas in young rats and in limbic areas in adults. Rats subjected to the MS15l environment that relates to natural conditions generally exhibited a different neurobiological profile than other groups. AFR rats, i.e. conventional control rats, were more similar to the putative most stressful condition MS360. Taken together, the networks examined in the present thesis are important for the establishment of normal social behaviour and derangements in these systems may result in neurobiological changes leading to the susceptibility for psychopathological conditions later in life.

Una de las principales cuestiones en farmacología molecular de los GPCR es entender los mecanismos estructurales de las siete hélices transmembrana (TM) que se producen para estabilizar ya sea Rg o los diferentes estados R*. Para entender el mecanismo que cambia el equilibrio del conjunto a un estado activo R* se construyeron tres de los receptores de la serotonina (5-HT4, 5-HT6, y 5 HT7) sobre la base de su información más reciente de cristalografía de rayos X. Dando lugar a dos modelos de cada receptor: una inactiva y otra activa. Los modelos, mejorados y evaluados con la ayuda de datos farmacológicos y químicos se utilizaron principalmente para comprender la interacción entre un ligando y su receptor y su mecanismo de acción. Estos hallazgos estructurales pueden a su vez resultar útiles para el diseño de nuevos fármacos más eficaces y selectivos. / One of the main questions in G protein coupled receptors (GPCRs) molecular pharmacology is to understand the structural arrangements of the seven transmembrane (TM) helices that occur to stabilize either the ground state (Rg) or different active states (R*) of the receptors. In order to understand the mechanism that shift the equilibrium of the ensemble to an active R* state models of the inactive and the active state of three serotonin receptors (5-HT4, 5-HT6, and 5-HT7) were built based on the latest information from X-ray crystallography. The resulting models were mainly used to understand the interaction between a ligand and its receptor and the mechanism of action. With the help of pharmacological and chemical data these models and complexes were improved and evaluated. These findings may prove valuable for structural based drug discovery efforts and facilitate the design of more effective and selective pharmaceuticals.

Thesis (Ph. D.)--University of Washington, 2007. / Vita. Includes bibliographical references (leaves 128-140).

Diss. (sammanfattning) Stockholm : Karol. inst., 2004. / Härtill 4 uppsatser.

Diss. Linköping : Univ., 2003.

Diss. (sammanfattning) Stockholm : Karol. inst. / Härtill 5 uppsatser.

Thesis (Ph. D.)--Case Western Reserve University, 2006. / [School of Medicine] Department of Biochemistry. Includes bibliographical references. Available online via OhioLINK's ETD Center.

Depuis des années, l’imagerie TEP des récepteurs 5-HT1A a permis une compréhension accrue du rôle physiopathologique de ces récepteurs. Toutefois les radiotraceurs actuels ne permettent pas d’évaluer le couplage entre récepteurs 5-HT1A et protéines G, susceptible d’être altéré au cours de pathologies. Les travaux effectués au cours de cette thèse visent à promouvoir l’utilisation de techniques d’imagerie translationnelles pour explorer le couplage des récepteurs 5-HT1A in vivo. La première partie a consisté à évaluer un agoniste des récepteurs 5-HT1A, le F13640, comme potentiel radiotraceur TEP. L’ensemble des résultats suggère que le [18F]F13640 est spécifique des récepteurs 5-HT1A couplés, avec des propriétés inédites par rapport aux radiotraceurs classiques.La deuxième partie a consisté à évaluer l’intérêt de l’imagerie des récepteurs 5-HT1A couplés. Les variations de densité de récepteurs couplés et totaux ont été comparées en autoradiographie postmortem au cours de la maladie d’Alzheimer. La fixation du [18F]F13640 dans l’hippocampe est diminuée dès les premiers stades, tandis que la fixation du [18F]MPPF n’est réduite qu’aux stades avancés. Ces observations démontrent la complémentarité entre traceurs agonistes et antagonistes des récepteurs 5-HT1A en imagerie TEP.La dernière partie s’est focalisée sur le concept d’agonisme biaisé, impliquant la possibilité de cibler différentes populations de récepteurs 5-HT1A en fonction de leur couplage aux protéines G. Le F13640 a été comparé au F15599 à doses pharmacologiques en imagerie TEP et en IRMf. Chez le rat, ces deux agonistes produisent des réponses hémodynamiques et métaboliques différentes. Chez le chat, ils diffèrent également en termes d’occupation des récepteurs et de réponse hémodynamique conséquente. L’ensemble des données est en faveur d’une stimulation préférentielle des récepteurs postsynaptiques par le F15599 par rapport aux autorécepteurs, contrairement au F13640 / Since the 1990s, PET imaging of 5-HT1A receptors has led to an increased understanding of the pathophysiological role of these receptors. However, the coupling between 5-HT1A receptors and G-proteins, which may be altered during pathologies, cannot be explored using current radiotracers. The work carried out in this thesis aims to promote the use of translational imaging techniques to explore the coupling of 5-HT1A receptors in vivo. In the first part, we evaluated the 5-HT1A receptor agonist F13640 as a PET radiotracer candidate. Taken together, the results suggest that [18F]F13640 binds specifically to coupled 5-HT1A receptors and displays novel properties and distribution pattern compared to classical 5-HT1A radiotracers. The second part was a proof-of-concept study regarding the interest of coupled 5-HT1A receptors imaging. Densities of coupled and total receptors were compared in postmortem autoradiography during Alzheimer’s disease. [18F]F13640 binding in hippocampus was decreased in the early stages, whereas [18F]MPPF binding was reduced in the advanced stages only. These results confirm the complementarity between 5-HT1A receptor agonists and antagonist tracers in PET imaging.In the last part we focused on the concept of biased agonism, which implies the possibility of targeting different populations of 5-HT1A receptors depending on their coupling with G-proteins. F13640 and F15599 were compared at pharmacological doses using PET and fMRI imaging. The two agonists produce different hemodynamic and metabolic responses in rat brain. They also differ in cat brain in terms of receptor occupancy and subsequent hemodynamic responses. Taken together, the results are consistent with a preferential stimulation of postsynaptic receptors over autoreceptors for F15599, in contrast with F13640

A provocação social é um método utilizado em animais de laboratório para a indução de elevados níveis de agressividade, produzindo padrões comportamentais semelhantes ao de indivíduos violentos. Estudos prévios utilizando drogas que atuam seletivamente sobre os receptores 5-HT1A e 5-HT1B demonstraram uma redução pronunciada no comportamento agressivo. Um dos mais importantes sítios de ação para esses agentes serotonérgicos é o córtex pré-frontal, uma região cerebral particularmente relevante no controle inibitório da agressividade e da impulsividade. O objetivo do presente estudo foi verificar os possíveis efeitos anti-agressivos da microinjeção de 8-OH-DPAT e CP-93,129 (agonistas específicos dos receptores 5-HT1A e 5-HT1B, respectivamente) na região ventro orbital do córtex pré-frontal de camundongos machos provocados socialmente. Para confirmar a especificidade do receptor, antagonistas 5-HT1A e 5-HT1B (WAY-100,635 e SB-224,289, respectivamente) também foram microinjetados na mesma região cerebral. 8-OH-DPAT na dose de 1.0 µg reduziu significativamente a freqüência de mordidas. A menor dose de CP- 93,129 (0.1 µg) também diminuiu o número de mordidas e de ataques laterais. Tais efeitos anti-agressivos não foram acompanhados por alterações no restante do repertório comportamental. A participação específica desses receptores foi verificada pela reversão dos efeitos com a utilização de WAY-100,635 (10.0 µg) e SB-224,289 (1.0 µg). Nossos resultados confirmam o envolvimento da região VO CPF e dos receptores 5-HT1A e 5-HT1B na modulação de altos níveis de agressividade, sem conseqüentes alterações em outras rotinas motoras. / Social instigation is used in rodents to induce high levels of aggression, a pattern of behavior similar to that of violent individuals. This procedure consists of a brief exposure to a provocative stimulus male, before direct confrontation with an intruder. Studies using 5- HT1A and 5-HT1B agonist receptors show a reduction in aggressive behavior. An important site of action for these drugs is the ventral orbito frontal cortex (VO PFC), an area of the brain which is particularly relevant in the inhibitory control of aggressiveness and impulsiveness. The objective of the present study was to assess the anti-aggressive effects of 5-HT1A and 5- HT1B agonist receptors (8-OH-DPAT and CP-93,129) on the VO PFC of socially provoked male mice. To confirm the specificity of the receptor, 5-HT1A and 5-HT1B antagonist receptors (WAY-100,635 and SB-224,289) were microinjected into the same area, in order to reverse the agonist effects. 8-OH-DPAT at 1.0 µg dose reduced the frequency of attack bites. The lowest dose of CP-93,129 (0.1 µg) also decreased the number of attack bites and lateral threats. The anti-aggressive effects were not accompanied by impairment of non-aggressive activities. Specific participation of the 1A and 1B receptors was verified by reversal of antiaggressive effects using selective antagonists WAY-100,635 (10.0 µg) and SB-224,289 (1.0 µg). In conclusion, the decrease in aggressiveness observed with microinjections of 5-HT1A and 5-HT1B receptor agonists into the VO PFC of socially provoked mice, supports the hypothesis that activation of these receptors modulates high levels of aggression in a behaviorally specific manner.

La mélatonine est une neurohormone sécrétée en période nocturne dans la glande pinéale. Elle régule les rythmes biologiques et influe sur différents processus physiologiques. Son implication ainsi que celle de la sérotonine, un neurotransmetteur, dans certains troubles de l’humeur font des récepteurs associés à ces deux hormones (MT1, MT2 et 5-HT2C respectivement) des cibles innovantes pour le développement de nouveaux antidépresseurs. Dans le cadre de cette thèse, des ligands mixtes mélatoninergiques et sérotoninergiques en série 7-azaindolique ont été synthétisés et testés biologiquement. L’élaboration de dérivés furo[3,2-b]pyridiniques a permis d’évaluer le potentiel biologique de ce squelette original et de mettre au point une nouvelle méthode de synthèse de ce motif. Ces travaux ont également été l’occasion d’étudier l’influence sur l’affinité et l’activité mélatoninergiques de la présence de différents groupements aryles plus ou moins volumineux en position 2 du noyau. Le dernier objectif a consisté dans le développement d’une voie d’accès à des analogues furopyridiniques tricycliques. Le raisonnement méthodologique poursuivi réside dans la mise en place d’une séquence réactionnelle permettant d’accéder aux structures désirées via une procédure courte et efficace. / Melatonin is a neurohormone secreted in the pineal gland during dark phases. This regulator of the biological clock is thus involved in several physiological process. Melatonin and serotonin, a neurotransmitter, are involved in some mood disorders, leading to consider associated receptors (MT1, MT2 and 5-HT2C respectively) as innovative targets for the development of new antidepressant.During this PhD, some 7-azaindolic ligands with both melatoninergic and serotoninergic activity were synthesized and tested from a biological point of view.Elaboration of furo[3,2-b]pyridinic derivatives allow us to evaluate the biological potential of this scaffold and to develop a new synthetic pathway to this pattern. This work has been the opportunity to study the influence of bulky aryl groups at C2 position over affinity and activity of these molecules towards melatoninergic receptors.The last aim consisted in developing a new methodology to access tricyclic furopyridinic analogues with a short and efficient chemical sequence.