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

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

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Protein structure predication is a field of computational molecular modeling with an enormous potential for improvement. Side-chain geometry prediction is a critical component of this process that is crucial for computational protein structure predication as well as crystallographers in refining experimentally determined protein crystal structures. The cornerstone of side-chain geometry prediction are side-chain rotamer libraries, usually obtained through exhaustive statistical analysis of existing protein structures. Little is known, however, about the driving forces leading to the preference or suitability of one rotamer over another. Construction of 3D hydropathic interaction maps for nearly 30,000 tyrosines extracted from the PDB reveals their environments, in terms of hydrophobic and polar (collectively “hydropathic”) interactions. Using a unique 3D similarity metric, these environments were clustered with k-means. In the ϕ, ψ region (–200° < ϕ < –155°; –205° < ψ < –160°) representing 631 tyrosines, clustering reduced the set to 14 unique hydropathic environments, with most diversity arising from favorable hydrophobic interactions. Polar interactions for tyrosine include ubiquitous hydrogen bonding with the phenolic OH and a handful of unique environments surrounding the backbone. The memberships of all but one of the 14 environments are dominated by a single χ1/χ2 rotamer. Each tyrosine residue attempts to fulfill its hydropathic valence. Structural water molecules are thus used in a variety of roles throughout protein structure. A second project involves elucidating the 3D structure of CRIP1a, a cannabinoid 1 receptor (CB1R) binding protein that could provide information for designing small molecules targeting the CRIP1a-CB1R interaction. The CRIP1a protein was produced in high purity. Crystallization experiments failed, both with and without the last 9 or 12 amino acid peptide of the CB1R C-terminus. Attempts were made to use NMR for structure determination; however, the protein precipitated out during data acquisition. A model was thus built computationally to which the CB1R C-terminus peptide was docked. HINT was used in selecting optimum models and analyzing interactions involved in the CRIP1a-CB1R complex. The final model demonstrated key putative interactions between CRIP1a and CB1R while also predicting highly flexible areas of the CRIP1a possibly contributing to the difficulties faced during crystallization.

Le cannabis produit de nombreux effets psychologiques et physiologiques sur le corps humain. Les molécules contenues dans cette plante, désignées comme « phytocannabinoïdes », activent un système endogène qu’on appelle le système endocannabinoïde (eCB). Les effets de la consommation de cannabis sur la vision ont déjà été décrits sans cependant de formulation sur les mécanismes sous-jacents. Ces résultats comportementaux suggèrent, malgré tout, la présence de ce système eCB dans le système visuel, et particulièrement dans la rétine. Cette thèse vise donc à caractériser l’expression, la localisation et le rôle du système eCB dans la rétine du singe vervet, une espèce animale ayant un système visuel semblable à celui de l’humain. Nous avons mis au point un protocole expérimental d’immunohistochimie décrit dans l’article apparaissant dans l’Annexe I que nous avons utilisé pour répondre à notre objectif principal. Dans une première série de quatre articles, nous avons ainsi caractérisé l’expression et la localisation de deux récepteurs eCBs reconnus, les récepteurs cannabinoïdes de type 1 (CB1R) et de type 2 (CB2R), et d’un 3e présumé récepteur aux cannabinoïdes, le récepteur GPR55. Dans l’article 1, nous avons démontré que CB1R et une enzyme clé de ce système, la fatty acid amide hydrolase (FAAH), sont exprimés dans les parties centrale et périphérique de la rétine, et abondamment présents dans la fovéa, une région où l’acuité visuelle est maximale. Dans l’article 2, nous avons localisé le CB2R dans des cellules gliales de la rétine : les cellules de Müller et nous avons proposé un modèle sur l’action de cette protéine dans la fonction rétinienne faisant appel à une cascade chimique impliquant les canaux potassiques. Dans l’article 3, nous avons observé le GPR55 exclusivement dans les bâtonnets qui sont responsables de la vision scotopique et nous avons soumis un deuxième modèle de fonctionnement de ce récepteur par le biais d'une modulation des canaux calciques et sodiques des bâtonnets. Vu que ces 3 récepteurs se retrouvent dans des cellules distinctes, nous avons suggéré leur rôle primordial dans l’analyse de l’information visuelle au niveau rétinien. Dans l’article 4, nous avons effectué une analyse comparative de l’expression du système eCB dans la rétine de souris, de toupayes (petits mammifères insectivores qui sont sont considérés comme l’étape intermédiaire entre les rongeurs et les primates) et de deux espèces de singe (le vervet et le rhésus). Ces résultats nous ont menés à présenter une hypothèse évolutionniste quant à l’apparition et à la fonction précise de ces récepteurs. Dans les articles subséquents, nous avons confirmé notre hypothèse sur le rôle spécifique de ces trois récepteurs par l’utilisation de l’électrorétinographie (ERG) après injection intravitréenne d’agonistes et d’antagonistes de ces récepteurs. Nous avons conclu sur leur influence indéniable dans le processus visuel rétinien chez le primate. Dans l’article 5, nous avons établi le protocole d’enregistrement ERG normalisé sur le singe vervet, et nous avons produit un atlas d’ondes ERG spécifique à cette espèce, selon les règles de l’International Society for Clinical Electrophysiology of Vision (ISCEV). Les patrons électrorétinographiques se sont avérés semblables à ceux de l’humain et ont confirmé la similarité entre ces deux espèces. Dans l’article 6, nous avons démontré que le blocage de CB1R ou CB2R entraine une modification de l’électrorétinogramme, tant au niveau photopique que scotopique, ce qui supporte l’implication de ces récepteurs dans la modulation des ondes de l’ERG. Finalement, dans l’article 7, nous avons confirmé le modèle neurochimique proposé dans l’article 3 pour expliquer le rôle fonctionnel de GPR55, en montrant que l’activation ou le blocage de ce récepteur, respectivement par un agoniste (lysophosphatidylglucoside, LPG) ou un antagoniste (CID16020046), entraine soit une augmentation ou une baisse significative de l’ERG scotopique seulement. Ces données, prises ensemble, démontrent que les récepteurs CB1R, CB2R et GPR55 sont exprimés dans des types cellulaires bien distincts de la rétine du singe et ont chacun un rôle spécifique. L’importance de notre travail se manifeste aussi par des applications cliniques en permettant le développement de cibles pharmacologiques potentielles dans le traitement des maladies de la rétine. / Cannabis produces a range of psychological and physiological effects on the human body. Cannabinoids are the chemical compounds found in cannabis that activate an endogenous system, termed the endocannabinoid (eCB) system. Reports made in the 1970s have noted that cannabis consumption affects vision. It is therefore suggested that the eCB system is present in the visual system, particularly in the retina. This thesis aims at characterizing the expression, localization, and role of the eCB system in the vervet monkey retina. This animal model has a similar visual system as humans. Using immunohistochemistry methods presented in the article of Annexe I, we have established an experimental protocol to answer our goal. In the first series of four articles, we have characterized the expression and localization of the cannabinoid receptor 1 (CB1R), cannabinoid receptor 2 (CB2R), and the putative cannabinoid receptor GPR55. In Article 1, we have demonstrated that CB1R and a key enzyme of this system, FAAH (fatty acid amide hydrolase), are expressed in the central and peripheral retina, but heavily present in the fovea, the retinal region responsible for high acuity vision. In Article 2, we have localized CB2R in the glial Müller cells and hypothesized a possible mechanism of action of CB2R involving potassium buffering. In Article 3, we found that GPR55 is exclusively expressed in rods and have proposed its role through the modulation of calcium and sodium channels in rods. Given that these three receptors are segregated in the vervet monkey retina, we suggested that they might have distinct roles in retinal physiology. In Article 4, we reported a comparative analysis of the expression of the eCB system components in the retina of rodents, tree shrews (small mammals considered as early primates), and monkeys. This paper provides evidence that the eCB system is differently expressed in the retina of these mammals and suggests a distinctive role of eCBs in visual processing. In the subsequent series of three articles, we confirmed their suggested roles in the retina by using electroretinography (ERG) and intravitreal injections of agonist and antagonist of these receptors. We concluded that they indeed play important roles in the retina. In Article 5, we developed a standard protocol for ERG testing in our animal model and have published an ERG atlas with normalized amplitudes and latency values similar to that of humans, following the guidelines of the International Society for Clinical Electrophysiology of Vision. In Article 6, we showed that blockade of CB1R or CB2R with specific antagonists modifies the ERG, both in photopic and scotopic conditions, which confirms the implication of these receptors in normal retinal function. Finally, in Article 7 (expression of GPR55 in rods only), we confirmed the suggest role of GPR55 in rods by showing that activation or blockade of GPR55 with a specific agonist (lysophosphatidylglucoside) or antagonist (CID16020046) increases or decreases the amplitude of the scotopic ERG waveforms. Taken together, these articles demonstrate that CB1R, CB2R, and GPR55 are differentially expressed in the vervet monkey retina and have distinct roles. This work has also clinical relevance in the way that we have discovered new pharmacological targets that can be used for treatment of many retinal diseases.

Classically, endogenous fatty acid ethanolamides and their derivatives that bind to the cannabinoid receptors and trigger a signalling pathway are referred to as endocannabinoids. Although derivatives of arachidonic acid, including arachidonylethanolamine or anandamide, are the known endogenous ligands for cannabinoid receptors, other fatty acid ethanolamides or N-acylethanolamines (NAE) that vary in carbon chain length and saturation occur ubiquitously in eukaryotic organisms and play an important role in their physiology and development. The metabolic pathway for NAEs is highly conserved among eukaryotes and well characterised in mammalian systems. Although NAE pathway is only partly elucidated in plants, significant progress has been made in the past 20 years in understanding the implications of the metabolism of saturated and unsaturated endocannabinoid-like molecules in plant development and growth. The latest advancements in the field of plant endocannabinoid research are reviewed. Key Concepts Endocannabinoids are endogenous ligands of cannabinoid receptors in mammalian systems. Endocannabinoids belong to a class of small bioactive lipid molecules that are derivatives of fatty acids including their ethanolamides, referred to as N-acylethanolamines. N-Acylethanolamines are ubiquitous and their metabolic pathway is highly conserved among eukaryotes. In higher plants, only 12–18C N-acylethanolamines have been identified and their metabolic pathway is partly elucidated. The endocannabinoid-like lipids play an important role in seed germination, seedling development, flowering and cellular organisation. In plants, N-acylethanolamines also participate in mediating responses to biotic and abiotic stress.

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Atherosclerosis is a macrophage-dominated nonresolving inflammatory disease of the arterial wall. Macrophage processes, including apoptosis, influence lesion development in atherosclerosis. Cannabinoids, compounds structurally related to Δ9-tetrahydrocannabinol (THC), the active ingredient in marijuana, exert their effects through cannabinoid receptors, CB1 and CB2. Cannabinoid treatment, THC or Win55,212-2, reduces atherosclerosis in ApoE-null mice by a mechanism thought to involve CB2. However, the exact role of CB2 in atherosclerosis remains unclear. We found that CB2-null macrophages are resistant to oxysterol/oxLDL-induced apoptosis leading us to hypothesize that CB2 may modulate macrophage apoptosis in atherosclerosis. To determine the functions of CB2 in atherosclerosis, we fed low density lipoprotein receptor-null (Ldlr-/-) and Ldlr-/- mice genetically deficient in CB2, an atherogenic diet for 8 and 12 weeks. CB2 deficiency did not significantly affect aortic root lesion area after 8 or 12 weeks; however, after 12 weeks, CB2-deficient lesions displayed increased lesional macrophage and smooth muscle cell (SMC) content and a ~2-fold reduction in lesional apoptosis. CB2-deficienct lesions also displayed reduced collagen content and elevated elastin fiber fragmentation that was associated with elevated levels of the extracellular matrix degrading enzyme, matrix metalloproteinase 9 (MMP9). These results demonstrate that although CB2 signaling does not affect atherosclerotic lesion size it does modulate lesional apoptosis, cellularity and ECM composition. Ldlr-/- and CB2-deficient Ldlr-/- mice were also subjected to daily treatments with Win55,212-2, a synthetic cannabinoid, over the last 2 weeks of an 8 week atherogenic diet to identify CB2-dependent and CB2-independent effects of cannabinoid receptor stimulation on atherosclerosis. Win55,212-2 did not affect hypercholesterolemia, aortic root lesion area, lesional macrophage infiltration, or ECM composition in either genotype but did significantly reduce total plasma triglyceride levels and lesional SMC content, independent of CB2. Surprisingly, lesional apoptosis was dose-dependently repressed by Win55,212-2 in Ldlr-/- mice by a CB2-dependent mechanism. All together, these results support the suggestion that CB2 may be a target for novel therapies aimed at modulating lesional apoptosis and cellularity to increase lesion stability and reduce the vulnerability to rupture.

The impacts of exogenous cannabinoids, such as the chemical constituents of Cannabis sativa like cannabidiol (CBD), on brain regions having a modest number of cannabinoid receptors, for example, the ventromedial hypothalamus, are not yet surely knew. A few researches have shown evidence that ventromedial hypothalamus (VMH) neurons play a role in modulating innate fear-induced behavioural reactions in rodents submitted to experimental models of panic attack, for example those based on prey versus wild snake confrontation paradigm. The panic attack-like state was also potentially induced in laboratory animals by N-Methyl-D-aspartate (NMDA), an excitatory amino acid, which stimulates neurons that organize defensive behavioural reactions in the central nervous system. Despite the fact that CB1 receptor-mediated endocannabinoid signaling mechanism underlies the antiaversive effect of exogenous anandamide in medial hypothalamus, there is still a lack of morphological evidence to support the distribution of CB1 receptors in the VMH. Henceforth, this study was designed to explore the specific pattern of distribution of the CB1 receptors in the VMH and, subsequently, the implication of these receptors in the endocannabinoidmodulated defensive behavioural responses followed by fear-induced antinociception evoked by NMDA microinjected in the VMH. A stainless steel guide-cannula was embedded in the rodent\'s brain coordinated towards VMH by means of stareotaxic surgery. Three different doses of cannabidiol (CBD) were microinjected in the VMH. The most effective dose was used after the pretreatment with the CB1 receptor-antagonist AM251, followed by NMDA microinjection in the VMH. The outcomes demonstrated that the defensive behavioural responses evoked in response to intra-VMH administration of NMDA (6 nmol) were decreased by intra-hypothalamic microinjections of CBD at the highest dose (100 nmol).These effects, however, were blocked by the administration of the CB1 receptor-antagonist AM251 (100 pmol) in the VMH. In addition, the fear-induced antinociception elicited by VMH chemical stimulation diminished after the VMH treatment with CBD, an effect reversed by the intra-diencephalic pretreatment with AM251. These findings suggested that CBD causes panicolytic-like effects when administered in the VMH, and that antiaversive effect recruits the CB1 receptor-endocannabinoid signaling mechanism in VMH. / O papel dos canabinoides exógenos nas regiões do cérebro com um número modesto de receptores cannabinoides, por exemplo, o hipotálamo ventromedial, ainda não está plenamente esclarecido. Algumas pesquisas de nosso grupo, não obstante, mostraram o hipotálamo ventromedial (HVM) exerce modulação de reações comportamentais provocadas pelo medo inato em animais submetidos a um modelo de ataques de pânico. Crises de pânico foram induzidas em animais de laboratório por N-metil-D-aspartato (NMDA), um aminoácido excitatório que, ao ser microinjetado em estruturas do sistema encefálico de aversão, estimula reações comportamentais defensivas no sistema nervoso central que mimetizam as respostas defensivas eliciadas por roedores confrontados com serpentes. Apesar do mecanismo de sinalização endocanabinoide mediado pelos receptores CB1 desempenhar um papel na modulação da neurotransmissão excitadora e inibitória no SNC, ainda há escassez de evidências morfológicas que embasem a distribuição dos receptores CB1 no HVM. Por conseguinte, este estudo foi idealizado para explorar a forma específica de distribuição dos receptores CB1 no HVM e, posteriormente, estudar a implicação desses receptores na modulação de respostas comportamentais defensivas, seguidas por antinocicepção induzida pelo medo, moduladas por endocanabinoides e evocadas por microinjetação de NMDA no HVM. Uma cânula-guia feita de aço inoxidável foi implantada no cérebro do roedor, e direcionada para o HVM por meio de cirurgia estareotóxica. Três diferentes doses de cannabidiol (CBD) foram microinjetadas no HVM. A dosagem mais eficaz foi utilizada após o pré-tratamento do hipotálamo medial com um antagonista do receptor CB1, o AM251, seguido da microinjeção NMDA no HVM. Os resultados demonstraram que as respostascomportamentais defensivas evocadas em resposta à administração intra-HVM de NMDA (6 nmol) foram diminuídas por microinjeções intra-hipotalâmicas de CBD na dose mais alta (100 nmol). Estes efeitos, no entanto, foram atenuados pela administração do antagonista do receptor CB1, AM251, na dose de 100 pmol no HVM. Além disso, a antinocicepção induzida pelo medo foi atenuada pela administração intra-diencefálica de CBA, o que foi revertido pelo pré-tratamenot do HVM com AM251. Esses dados sugerem que o CBD causa efeitos panicolíticos, quando administrado no HVM, envolvendo o mecanismo de sinalização do receptor CB1-endocannabinoide.

L’architecture polarisée des neurones est mise en place est maintenue grâce à un adressage hautement contrôlé de protéines vers l’axone ou vers le compartiment somatodendritique. Parmi ces protéines, les récepteurs aux protéines G (RCPG) neuronaux sont des cibles pharmacologiques clés. Cependant, leur pharmacologie est généralement étudiée dans des lignées cellulaires non polarisées et les résultats obtenus dans ces systèmes ne caractérisent pas correctement les effets physiologiques de l’activation des RCPG présents dans le cerveau. Par conséquent, un des principaux sujets de recherche de notre équipe est de comprendre comment la polarité neuronale influe sur la pharmacologie des RCPG, en étudiant l’un des RCPG les plus abondants dans le cerveau : le récepteur cannabinoïque de type-1 (CB1R). Les études précédentes de notre groupe ont suggéré que CB1R acquiert une polarisation axonale grâce à un adressage transcytotique : après leur synthèse, ces récepteurs apparaissent sur la membrane plasmique somatodendritique d’où ils sont rapidement enlevés par endocytose constitutive puis adressés à la membrane plasmique axonale où ils s’accumulent du fait d’une endocytose réduite. Au début de ma thèse, nous avons directement mesuré cette endocytose différentielle et le transport transcytotique de CB1R en utilisant des neurones de rats mis en culture dans des dispositifs microfluidiques. De plus, nous avons montré que des traitements pharmacologiques prolongés peuvent fortement changer la distribution de RCPG à la surface neuronale. Ces résultats démontrent que l’équilibre endocytotique dépendant du compartiment neuronal, qui est contrôlable pharmacologiquement, est important pour la distribution des RCPG neuronaux. Dans une seconde partie, nous avons étudié si le trafic différentiel de CB1R entre axones et dendrites est corrélé avec une pharmacologie différentielle. CB1R est majoritairement couplé à des protéines de type Gi/o et est connu pour inhiber la production d’AMPc. Nous avons donc développé l’imagerie par Föster Resonance Energy Transfer (FRET) appliqué aux cultures de neurones d’hippocampe de rats afin de mesurer la modulation de la voie de signalisation AMPc/PKA en aval de CB1R endogènes dans l’ensemble des compartiments neuronaux : somata, dendrites, mais aussi dans les axones matures très fins. Nos résultats montrent que CB1R possède une pharmacologie différente entre les dendrites et les axones. Notamment, son activation conduit à une diminution plus forte de l’activité basale de la PKA dans les axones comparé aux dendrites, lié au plus grand nombre de récepteurs présents sur la membrane de ce compartiment. De plus, nous démontrons que, contrairement aux récepteurs axonaux, les CB1R somatodendritiques inhibent constitutivement la voie AMPc/PKA. Cette différence est due à la distribution polarisée de la DAGLipase, l’enzyme synthétisant l’endocannabinoïde principal, le 2-arachidonoyglycerol (2-AG). De plus, l’inhibition pharmacologique de la DAGL modifie l’efficacité de plusieurs agonistes de CB1R dans le compartiment somatodendritique mais pas dans l’axone. Cet effet pourrait être dû à une modulation allostérique. Dans une troisième partie, nous avons étudié si les résultats ci-dessus peuvent être généralisés à d’autres RCPG. Etant donné que l’adressage axonal et la pharmacologie in vitro des récepteurs sérotoninergiques 5-HT1B montrent de fortes similitudes avec ceux de CB1R, nous avons étudié la pharmacologie de ces récepteurs en utilisant la technique de FRET développée précédemment. De façon similaire, nous avons trouvé une pharmacologie différentielle entre l’axone et les dendrites. / Polarized neuronal architecture is achieved and maintained mainly through highly controlled targeting of proteins to axons versus to the somatodendritic compartment. Among these proteins, neuronal G protein coupled receptors (GPCRs) are key therapeutic targets. However, their pharmacology is generally studied in non-polarized cell lines, and results obtained in such systems likely do not fully characterize the physiological effects of brain GPCR activation. Therefore, a main research subject of our group is to understand how neuronal polarity influences GPCR pharmacology, by studying one of the most abundant GPCR in the brain: the type-1 cannabinoid receptor (CB1R). Previous studies of the group suggested that CB1Rs achieve axonal polarization through transcytotic targeting: after their synthesis, these receptors appear on the somatodendritic plasma membrane from where they are removed rapidly by constitutive endocytosis and then targeted to the axonal plasma membrane where they accumulate due to relatively reduced endocytosis rate. At the beginning of my PhD project we directly demonstrated this differential endocytosis and transcytotic transport of CB1Rs by using cultured neurons in microfluidic devices. Moreover, we showed that chronic pharmacological treatments may strongly change neuronal GPCR distribution on the neuronal surface. These results demonstrate that subdomain-dependent steady-state endocytosis, which is pharmacologically controllable, is important for GPCR distribution in neurons. In a second part, we asked if differential traffic of CB1Rs between axons and dendrites is correlated with differential pharmacology. CB1R is predominantly coupled to Gi/o proteins and is known to inhibit cAMP production. Thus, we developed live Föster Resonance Energy Transfer (FRET) imaging in cultured hippocampal neurons in order to measure basal cAMP/PKA pathway modulation downstream of endogenous CB1Rs in all neuronal compartments: in somata, in dendrites but also in the very thin mature axons. Our results show that CB1R displays differential pharmacology between axon and dendrites. Notably, its activation leads to a stronger decrease of PKA activity in axons compared to dendrites, due to increased number of membrane receptors in this compartment. Moreover, we demonstrate that somatodendritic CB1Rs constitutively inhibit cAMP/PKA pathway, while axonal receptors do not. This difference is due to polarized distribution of DAGLipase, the enzyme that synthesizes the major endocannabinoid 2-arachidonoylglycerol (2-AG). Moreover, blocking DAGL by pharmacological treatment modifies somatodendritic, but not axonal effects of several CB1R agonists, possibly through allosteric action. In a third part, we asked if the above results may be generalized to other GPCRs. Because the axonal targeting and in vitro pharmacology of 5-HT1B serotonin receptors demonstrate strong similarities with CB1Rs, we studied their neuronal pharmacology by using the previously developed FRET technique. We found similar differential responses to pharmacological treatments between axon and dendrites. In a fourth part, we investigated the role of the threonine 210 (T210) residue in the constitutive activity of neuronal CB1R. We showed that the hypoactive mutant T210A-CB1R do not constitutively recruit signaling pathways even in somatodendritic compartment, where 2-AG is present. This result demonstrates that T210 is necessary for constitutive CB1R activation by 2-AG.Finally, previous results of our group demonstrated the involvement of CB1R in neuronal development. Notably, CB1R activation was shown to have an overall inhibitory effect on the development of polarized neuronal morphology. We established a bibliographic review on this subject. The published literature data suggest that not only neuronal polarization influences both CB1R traffic and pharmacology but CB1Rs also contribute to the achievement of neuronal polarization. (...)