Cannabinoid CB1 Receptor Research Articles

Repeated cocaine administration upregulates CB2 receptor expression in striatal medium-spiny neurons that express dopamine D1 receptors in mice.

Cannabinoid CB2 receptors (CB2R) are importantly involved in drug reward and addiction. However, the cellular mechanisms underlying CB2R action remain unclear. We have previously reported that cocaine self-administration upregulates CB2R expression in midbrain dopamine (DA) neurons. In the present study, we investigated whether cocaine or heroin also alters CB2R expression in striatal medium-spiny neuronsthat express dopamineD1 or D2 receptors (D1-MSNs, D2-MSNs) and microglia. Due to the concern of CB2R antibody specificity, we developed three mouse CB2-specific probes to detect CB2R mRNA using quantitative RT-PCR and RNAscope in situ hybridization (ISH) assays. We found that a single injection of cocaine failed to alter, while repeated cocaine injections or self-administration dose-dependently upregulated CB2R gene expression in both brain (cortex and striatum) and periphery (spleen). In contrast, repeated administration ofheroin produced a dose-dependent reduction in striatal CB2 mRNA expression. RNAscope ISH assays detected CB2R mRNA in striatal D1- and D2-MSNs, not in microglia. We then used transgenic CX3CR1eGFP/+ microglia reporter mice and D1- or D2-Cre-RiboTag mice to purify striatal microglia or ribosome-associated mRNAs from CX3CR1eGFP/+,D1-MSNs, or D2-MSNs, respectively. We found that CB2R upregulation occurred mainly in D1-MSNs, not in D2-MSNs or microglia, in the nucleus accumbens rather than the dorsal striatum. These findings indicate that repeated cocaine exposure may upregulate CB2R expression in both brain and spleen, with regional and cell type-specific profiles. In the striatum, CB2R upregulation occurs mainly in D1-MSNs in the nucleus accumbens. Given the important role of D1-MSNs in brain reward function, the present findings provide new insight into mechanisms by which brain CB2Rs modulate cocaine action.

Development of fluorinated and methoxylated benzothiazole derivatives as highly potent and selective cannabinoid CB2 receptor ligands

The upregulation of the CB2 receptors in neuroinflammation and cancer and their potential visualization with PET (positron emission tomography) could provide a valuable diagnostic and therapy-monitoring tool in such disorders. However, the availability of reliable CB2-selective imaging probes is still lacking in clinical practice. We have recently identified a benzothiazole-2-ylidine amide hit (6a) as a highly potent CB2 ligand. With the aim of enhancing its CB2 over CB1 selectivity and introducing structural sites suitable for radiolabeling, we herein describe the development of fluorinated and methoxylated benzothiazole derivatives endowed with extremely high CB2 binding affinity and an exclusive selectivity to the CB2 receptor. Compounds 14, 15, 18, 19, 21, 24 and 25 displayed subnanomolar CB2Ki values (ranging from 0.16 nM to 0.68 nM) and interestingly, all of the synthesized compounds completely lacked affinity at the CB1 receptor (Ki > 10,000 nM for all compounds), indicating their remarkably high CB2 over CB1 selectivity factors. The fluorinated analogs, 15 and 21, were evaluated for their in vitro metabolic stability in mouse and human liver microsomes (MLM and HLM). Both 15 and 21 displayed an exceptionally high stability (98% and 91% intact compounds, respectively) after 60 min incubation with MLM. Contrastingly, a 5- and 2.8-fold lower stability was demonstrated for compounds 15 and 21, respectively, upon incubation with HLM for 60 min. Taken together, our data present extremely potent and selective CB2 ligands as credible leads that can be further exploited for 18F- or 11C-radiolabeling and utilization as PET tracers.

Environmental Enrichment Rescues Endocannabinoid-Dependent Synaptic Plasticity Lost in Young Adult Male Mice after Ethanol Exposure during Adolescence.

Binge drinking (BD) is a serious health concern in adolescents as high ethanol (EtOH) consumption can have cognitive sequelae later in life. Remarkably, an enriched environment (EE) in adulthood significantly recovers memory in mice after adolescent BD, and the endocannabinoid, 2-arachydonoyl-glycerol (2-AG), rescues synaptic plasticity and memory impaired in adult rodents upon adolescent EtOH intake. However, the mechanisms by which EE improves memory are unknown. We investigated this in adolescent male C57BL/6J mice exposed to a drinking in the dark (DID) procedure four days per week for a duration of 4 weeks. After DID, the mice were nurtured under an EE for 2 weeks and were subjected to the Barnes Maze Test performed the last 5 days of withdrawal. The EE rescued memory and restored the EtOH-disrupted endocannabinoid (eCB)-dependent excitatory long-term depression at the dentate medial perforant path synapses (MPP-LTD). This recovery was dependent on both the cannabinoid CB1 receptor and group I metabotropic glutamate receptors (mGluRs) and required 2-AG. Also, the EE had a positive effect on mice exposed to water through the transient receptor potential vanilloid 1 (TRPV1) and anandamide (AEA)-dependent MPP long-term potentiation (MPP-LTP). Taken together, EE positively impacts different forms of excitatory synaptic plasticity in water- and EtOH-exposed brains.

The Role of Pyroptosis in Ischemic and Reperfusion Injury of the Heart.

While ischemia itself can kill heart muscle, much of the infarction after a transient period of coronary artery occlusion has been found to result from injury during reperfusion. Here we review the role of inflammation and possible pyroptosis in myocardial reperfusion injury. Current evidence suggests pyroptosis's contribution to infarction may be considerable. Pyroptosis occurs when inflammasomes activate caspases that in turn cleave off an N-terminal fragment of gasdermin D. This active fragment makes large pores in the cell membrane thus killing the cell. Inhibition of inflammation enhances cardiac tolerance to ischemia and reperfusion injury. Stimulation of the purinergic P2X7 receptor and the β-adrenergic receptor and activation of nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) by toll-like receptor (TLR) agonists are all known to contribute to ischemia/reperfusion (I/R) cardiac injury through inflammation, potentially by pyroptosis. In contrast, stimulation of the cannabinoid CB2 receptor reduces I/R cardiac injury and inhibits this pathway. MicroRNAs, Akt, the phosphate and tension homology deleted on chromosome 10 protein (PTEN), pyruvate dehydrogenase and sirtuin-1 reportedly modulate inflammation in cardiomyocytes during I/R. Cryopyrin and caspase-1/4 inhibitors are reported to increase cardiac tolerance to ischemic and reperfusion cardiac injury, presumably by suppressing inflammasome-dependent inflammation. The ambiguity surrounding the role of pyroptosis in reperfusion injury arises because caspase-1 also activates cytotoxic interleukins and proteolytically degrades a surprisingly large number of cytosolic enzymes in addition to activating gasdermin D.

Basic neuroscience P-BN002. Morphine-, mitragynine- and THC-induced alterations of cannabinoid CB1 receptor immunoreactivity in brain hippocampal ca1 region of Swiss albino mice

Introduction . Problems pertaining to the large and growing abuse of plant-derived psychoactive substances are on the rise. Literature indicates that uncontrolled use of phytochemicals, such as opioids, Δ-9-tetrahydrocannabinol (THC) and mitragynine (main alkaloid of Mitragyna speciosa or Ketum plant) pose considerable harms and addictive burdens, including behavioural and neurological alterations in brain reward system. This study aimed to evaluate the neuronal changes in hippocampal CA1 region of brain mesolimbic system, particularly involving cannabinoid (CB1) receptor, induced by chronic exposure to morphine, mitragynine and THC. Methods . Twenty-four (n=24) male Swiss albino mice were subjected to daily administration of Tween 20-vehicle (1 ml/kg, ip, n=6), morphine sulphate (5 mg/kg, sc, n=6), mitragynine (5-25 mg/kg, ip, n=6), or THC (2 mg/kg, ip, n=6) for 28 days. On Day-29, mice brains were removed and processed for immunohistochemistry and Western Blot analyses for the expression of CB1 receptor protein. Results . Chronic treatment with morphine and mitragynine induced an up-regulation of CB1 receptor immunoreactivity in mice hippocampal CA1 region (p<0.05), a key brain reward area. In contrast, THC group showed significant down-regulation of CB1 receptor binding sites in CA1 hippocampal region (p<0.05). Conclusion . These findings suggest the involvement of brain CB1 receptors in the abuse liability of chronic morphine, mitragynine and THC intake.

Lack of the Transient Receptor Potential Vanilloid 1 Shifts Cannabinoid-Dependent Excitatory Synaptic Plasticity in the Dentate Gyrus of the Mouse Brain Hippocampus.

The transient receptor potential vanilloid 1 (TRPV1) participates in synaptic functions in the brain. In the dentate gyrus, post-synaptic TRPV1 in the granule cell (GC) dendritic spines mediates a type of long-term depression (LTD) of the excitatory medial perforant path (MPP) synapses independent of pre-synaptic cannabinoid CB1 receptors. As CB1 receptors also mediate LTD at these synapses, both CB1 and TRPV1 might be influencing the activity of each other acting from opposite synaptic sites. We tested this hypothesis in the MPP–GC synapses of mice lacking TRPV1 (TRPV1-/-). Unlike wild-type (WT) mice, low-frequency stimulation (10 min at 10 Hz) of TRPV1-/- MPP fibers elicited a form of long-term potentiation (LTP) that was dependent on (1) CB1 receptors, (2) the endocannabinoid 2-arachidonoylglycerol (2-AG), (3) rearrangement of actin filaments, and (4) nitric oxide signaling. These functional changes were associated with an increase in the maximum binding efficacy of guanosine-5′-O-(3-[35S]thiotriphosphate) ([35S]GTPγS) stimulated by the CB1 receptor agonist CP 55,940, and a significant decrease in receptor basal activation in the TRPV1-/- hippocampus. Finally, TRPV1-/- hippocampal synaptosomes showed an augmented level of the guanine nucleotide-binding (G) Gαi1, Gαi2, and Gαi3 protein alpha subunits. Altogether, the lack of TRPV1 modifies CB1 receptor signaling in the dentate gyrus and causes the shift from CB1 receptor-mediated LTD to LTP at the MPP–GC synapses.

Prediction of essential binding domains for the endocannabinoid N-arachidonoylethanolamine (AEA) in the brain cannabinoid CB1 receptor.

Δ9-tetrahydrocannabinol (Δ9-THC), the main active ingredient of Cannabis sativa (marijuana), interacts with the human brain cannabinoid (CB1) receptor and mimics pharmacological effects of endocannabinoids (eCBs) like N-arachidonylethanolamide (AEA). Due to its flexible nature of AEA structure with more than 15 rotatable bonds, establishing its binding mode to the CB1 receptor is elusive. The aim of the present study was to explore possible binding conformations of AEA within the binding pocket of the CB1 receptor confirmed in the recently available X-ray crystal structures of the CB1 receptor and predict essential AEA binding domains. We performed long time molecular dynamics (MD) simulations of plausible AEA docking poses until its receptor binding interactions became optimally established. Our simulation results revealed that AEA favors to bind to the hydrophobic channel (HC) of the CB1 receptor, suggesting that HC holds essential significance in AEA binding to the CB1 receptor. Our results also suggest that the Helix 2 (H2)/H3 region of the CB1 receptor is an AEA binding subsite privileged over the H7 region.

Cannabidiol in the prelimbic cortex modulates the comorbid condition between the chronic neuropathic pain and depression-like behaviour in rats: The role of medial prefrontal cortex 5-HT1A and CB1 receptors

The prelimbic division (PrL) of the medial prefrontal cortex (mPFC) is a cerebral division that is putatively implicated in the chronic pain and depression. We investigated the activity of PrL cortex neurons in Wistar rats that underwent chronic constriction injury (CCI) of sciatic nerve and were further subjected to the forced swimming (FS) test and mechanical allodynia (by von Frey test). The effect of blockade of synapses with cobalt chloride (CoCl2), and the treatment of the PrL cortex with cannabidiol (CBD), the CB1 receptor antagonist AM251 and the 5-HT1A receptor antagonist WAY-100635 were also investigated. Our results showed that CoCl2 decreased the time spent immobile during the FS test but did not alter mechanical allodynia. CBD (at 15, 30 and 60 nmol) in the PrL cortex also decreased the frequency and duration of immobility; however, only the dose of 30 nmol of CBD attenuated mechanical allodynia in rats with chronic NP. AM251 and WAY-100635 in the PrL cortex attenuated the antidepressive and analgesic effect caused by CBD but did not alter the immobility and the mechanical allodynia when administered alone. These data show that the PrL cortex is part of the neural substrate underlying the comorbidity between NP and depression. Also, the previous blockade of CB1 cannabinoid receptors and 5-HT1A serotonergic receptors in the PrL cortex attenuated the antidepressive and analgesics effect of the CBD. They also suggest that CBD could be a potential medicine for the treatment of depressive and pain symptoms in patients with chronic NP/depression comorbidity.

Cannabinoid Receptors in Myocardial Injury: A Brother Born to Rival.

Cannabinoid receptors typically include type 1 (CB1) and type 2 (CB2), and they have attracted extensive attention in the central nervous system (CNS) and immune system. Due to more in-depth studies in recent years, it has been found that the typical CB1 and CB2 receptors confer functional importance far beyond the CNS and immune system. In particular, many works have reported the critical involvement of the CB1 and CB2 receptors in myocardial injuries. Both pharmacological and genetic approaches have been used for studying CB1 and CB2 functions in these studies, revealing that the brother receptors have many basic differences and sometimes antagonistic functions in a variety of myocardial injuries, despite some sequence or location identity they share. Herein, we introduce the general differences of CB1 and CB2 cannabinoid receptors, and summarize the functional rivalries between the two brother receptors in the setting of myocardial injuries. We point out the importance of individual receptor-based modulation, instead of dual receptor modulators, when treating myocardial injuries.

Design of Negative and Positive Allosteric Modulators of the Cannabinoid CB2 Receptor Derived from the Natural Product Cannabidiol.

Cannabidiol (CBD), the second most abundant of the active compounds found in the Cannabis sativa plant, is of increasing interest because it is approved for human use and is neither euphorizing nor addictive. Here, we design and synthesize novel compounds taking into account that CBD is both a partial agonist, when it binds to the orthosteric site, and a negative allosteric modulator, when it binds to the allosteric site of the cannabinoid CB2 receptor. Molecular dynamic simulations and site-directed mutagenesis studies have identified the allosteric site near the receptor entrance. This knowledge has permitted to perform structure-guided design of negative and positive allosteric modulators of the CB2 receptor with potential therapeutic utility.

Cannabinoid Receptor 1 associates to different molecular complexes during GABAergic neuron maturation.

CB1 cannabinoid receptor is widely expressed in the central nervous system of animals from late prenatal development to adulthood. Appropriate activation and signaling of CB1 cannabinoid receptors in cortical interneurons are crucial during perinatal/postnatal ages and adolescence, when long-lasting changes in brain activity may elicit subsequent appearance of disorders in the adult brain. Here we used an optimized immunoprecipitation protocol based on specific antibodies followed by shot-gun proteomics to find CB1 interacting partners in postnatal rat GABAergic cortical neurons in vitro at two different stages of maturation. Besides describing new proteins associated with CB1 like dihydrolipoyllysine-residue acetyltransferase component of pyruvate dehydrogenase complex (DLAT), fatty acid synthase (FASN), tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein zeta (YWHAZ), voltage-dependent anion channel 1 (VDAC1), myosin phosphatase Rho-interacting protein (MPRIP) or usher syndrome type-1C protein-binding protein 1 (USHBP1), we show that the signaling complex of CB1 is different between maturational stages. Interestingly, the CB1 signaling complex is enriched at the more immature stage in mitochondrial associated proteins and metabolic molecular functions, whereas at more mature stage, CB1 complex is increased in maturation and synaptic-associated proteins. We describe also interacting partners specifically immunoprecipitated with either N-terminal or C-terminal CB1 directed antibodies. Our results highlight new players that may be affected by altered cannabinoid signaling at this critical window of postnatal cortical development.

Different Dietary n-3 Polyunsaturated Fatty Acid Formulations Distinctively Modify Fatty Acid and N-Acylethanolamine Profiles in Rat Brain

Abstract Objectives Dietary n-3 polyunsaturated fatty acids (n-3PUFA) may influence the brain fatty acid (FA) profile and, thereby, the biosynthesis of FA bioactive metabolite, such as N-acylethanolamines (NAE). We investigated the influence of different dietary formulation of n-3PUFA from vegetable or marine oils on rat FA incorporation and modulation of NAE biosynthesis. Methods Rats were fed for 10 weeks with diets containing 12% of fat from milk + 4% soybean oil and 4% of oils with different n-3 PUFA species: soybean oil as control (MilkFat), linseed oil with α-linolenic (ALA) (LSO), Buglossoides arvensis oil with ALA and stearidonic (SDA) (Buglos), fish oil with EPA and DHA (FO), Nannochloropsis microalga oil with EPA (Nanno) or Schizochytrium microalga oil with DHA (Schy). Brain FA and NAE profile were assessed LC-DAD-MS/MS. Statistical Kruskal-Wallis test followed by Dunn's correction was applied. Results Different dietary n-3PUFA formulations induced FA change in the brain, compared to MilkFat group, DHA levels remained unchanged despite its elevated intake with FO and Schy diets. However, we found 9 fold (P &amp;lt; 0.001) increase of EPA with FO, arachidonic (AA) decreased significantly about 16% (P &amp;lt; 0.05) with LSO and FO diets. n-6 PUFA docosatetraenoic (DTA) (26% P &amp;lt; 0.05) and docosapentaenoic (DPA) (73% P &amp;lt; 0.05) were reduced with FO, probably due to a competition with EPA in the incorporation into phospholipids. We observed a 44% (P &amp;lt; 0.05) significant decrease of N-arachidonoylethanolamine (AEA) with LSO and FO, and a reduction of N-linoleoylethanolamine (LEA) by 49% (P &amp;lt; 0.05) with LSO. On the other hand, we found an increase of N-eicosapentanoylethanolamine (EPEA), derived from EPA, by 225% (P &amp;lt; 0.05) with FO, compared to MilkFat group. Conclusions Our data indicate that reduction of AEA levels might attenuate its effects on the CB1 cannabinoid receptors, the main molecular target of the endogenous partial agonist AEA, which regulate physiological processes in the central nervous system. Therefore, in those pathophysiological conditions where is desirable to downregulate an overactive endocannabinoid system, a mixture of EPA and DHA as in FO, and ALA as in LSO, may potentially be a preferred nutritional source of n-3 PUFA. Funding Sources University of Cagliari (FIR 2019) and Fundação FCT (Portugal).

The bidirectional effect of prelimbic 5-hydroxytryptamine type-4 (5-HT4) receptors on ACPA-mediated aversive memory impairment in adult male Sprague-Dawley rats.

Objective(s):This study aimed at investigating the effect of serotonergic 5-HT4 receptor agonist/antagonist on memory consolidation deficit induced by ACPA (a potent, selective CB1 cannabinoid receptor agonist) in the pre-limbic (PL) cortex. Materials and Methods: We used the step-through passive avoidance test to evaluate memory consolidation of male Sprague-Dawley (SD) rats. Bilateral post-training microinjections of the drugs were done in a volume of 0.6 μl/rat into the PL area (0.3 μl per side).Results:The results showed a significant interaction between RS67333 hydrochloride (5-HT4 receptor agonist) or RS23597-190 hydrochloride (5-HT4 receptor antagonist) and ACPA on consolidation of aversive memory. RS67333 hydrochloride (0.5 μg/rat) enhanced consolidation of memory and its co-administration at the ineffective dose of 0.005 μg/rat with ineffective (0.001 μg/rat) or effective (0.1 μg/rat) doses of ACPA improved and prevented impairment of memory caused by ACPA, respectively. In other words, RS67333 had a bidirectional effect on ACPA-caused amnesia. While RS23597-190 hydrochloride had no effect on memory at the doses used (0.005, 0.01, 0.1, or 0.5 μg/rat); but its concomitant use with an effective dose of ACPA (0.1 μg/rat) potentiated amnesia. None of the drugs had an effect on locomotor activity.Conclusion:This study revealed that activation or deactivation of the 5-HT4 receptors in the PL may mediate the IA memory impairment induced by ACPA indicating a modulatory role for the 5-HT4 serotonergic receptors.

Rhodium(I)‐Catalyzed Enantioselective C(sp3)—H Functionalization viaCarbene‐Induced Asymmetric Intermolecular C—H Insertion†

Main observation and conclusionTransition‐metal‐catalyzed C—H insertion of metal‐carbene represents an excellent and powerful approach for C—H functionalization. However, despite remarkable advances in metal‐carbene chemistry, transition metal catalysts that are capable of enantioselective intermolecular carbene C—H insertion are mainly constrained to dirhodium(II) and iridium(III)‐based complexes. Herein, we disclose a new version of asymmetric carbene C—H insertion reaction with rhodium(I) catalyst. A highly enantioselective rhodium(I) complex‐catalyzed C(sp3)—H functionalization of 1,4‐cyclohexadienes with α‐aryl‐α‐diazoacetates was successfully developed. By using chiral bicyclo[2.2.2]‐octadiene as ligand, rhodium(I)‐carbene‐induced asymmetric intermolecular C—H insertion proceeds smoothly at room temperature, allowing access to a diverse variety of α‐aryl‐α‐cyclohexadienyl acetates and gem‐diaryl‐containing acetates in good yields with good to excellent enantioselectivities (up to 99% ee). Furthermore, the synthetic utility of the reaction was highlighted by facile synthesis of a novel cannabinoid CB1 receptor ligand. This method may offer a new opportunity for the development of therapeutically exploitable cannabinoid receptor type ligands in medicinal chemistry.

New insights into bisphenols induced obesity in zebrafish (Danio rerio): Activation of cannabinoid receptor CB1

Bisphenols (BPs), as widely used plastic additives, penetrate into our daily lives. BPs are considered endocrine disruptors and could potentially induce obesity. In this study, the effects of bisphenol A (BPA) and tetrabromobisphenol A (TBBPA) on food intake and lipid metabolism in zebrafish were determined. Moreover, the impact of BPA and TBBPA on the endocannabinoid system (ECS) of zebrafish was further explored by metabolomics, transcriptomics, and molecular docking analysis. Here we show that exposure to BPA and TBBPA at concentrations commonly found in the environment (20, 100, and 500 μg/L) led to hyperphagia and obesity in adult male zebrafish. Metabolomics and histopathological analysis revealed significant lipid accumulation in the liver of zebrafish exposed to BPA and TBBPA. The expression of ECS-related genes, in conjunction with RNA-Seq results, further indicated that BPA and TBBPA increased appetite and induced obesity by activating cannabinoid receptor type 1(CB1). Furthermore, molecular docking revealed that six representative BPs including BPA and TBBPA could bind to the CB1 receptor. Collectively, these findings indicate that CB1 may be a potential target for BPs to induce obesity.

Cannabinoid receptor CB2 ablation protects against TAU induced neurodegeneration

Tauopathies are a group of neurodegenerative diseases characterized by the alteration/aggregation of TAU protein, for which there is still no effective treatment. Therefore, new pharmacological targets are being sought, such as elements of the endocannabinoid system (ECS). We analysed the occurrence of changes in the ECS in tauopathies and their implication in the pathogenesis. By integrating gene expression analysis, immunofluorescence, genetic and adeno-associated virus expressing TAU mouse models, we found a TAU-dependent increase in CB2 receptor expression in hippocampal neurons, that occurs as an early event in the pathology and was maintained until late stages. These changes were accompanied by alterations in the endocannabinoid metabolism. Remarkably, CB2 ablation in mice protects from neurodegeneration induced by hTAUP301L overexpression, corroborated at the level of cognitive behaviour, synaptic plasticity, and aggregates of insoluble TAU. At the level of neuroinflammation, the absence of CB2 did not produce significant changes in concordance with a possible neuronal location rather than its classic glial expression in these models. These findings were corroborated in post-mortem samples of patients with Alzheimer’s disease, the most common tauopathy. Our results show that neurons with accumulated TAU induce the expression of the CB2 receptor, which enhances neurodegeneration. These results are important for our understanding of disease mechanisms, providing a novel therapeutic strategy to be investigated in tauopathies.

Modulation of Endocannabinoid Tone in Osteoblastic Differentiation of MC3T3-E1 Cells and in Mouse Bone Tissue over Time.

Bone is a highly complex and metabolically active tissue undergoing a continuous remodeling process, which endures throughout life. A complex cell-signaling system that plays role in regulating different physiological processes, including bone remodeling, is the endocannabinoid system (ECS). Bone mass expresses CB1 and CB2 cannabinoid receptors and enzymatic machinery responsible for the metabolism of their endogenous ligands, endocannabinoids (AEA and 2-AG). Exogenous AEA is reported to increase the early phase of human osteoblast differentiation in vitro. However, regarding this cell context little is known about how endocannabinoids and endocannabinoid-related N-acylethanolamines like PEA and OEA are modulated, in vitro, during cell differentiation and, in vivo, over time up to adulthood. Here we characterized the endocannabinoid tone during the different phases of the osteoblast differentiation process in MC3T3-E1 cells, and we measured endocannabinoid levels in mouse femurs at life cycle stages characterized by highly active bone growth (i.e., of juvenile, young adult, and mature adult bone). Endocannabinoid tone was significantly altered during osteoblast differentiation, with substantial OEA increment, decline in 2-AG and AEA, and consistent modulation of their metabolic enzymes in maturing and mineralized MC3T3-E1 cells. Similarly, in femurs, we found substantial, age-related, decline in 2-AG, OEA, and PEA. These findings can expand existing knowledge underlying physiological bone cell function and contribute to therapeutic strategies for preventing bone-related metabolic changes accruing through lifespan.

Corrigendum

Chemical Biology & Drug DesignVolume 97, Issue 6 p. 1210-1210 CORRIGENDUMFree Access Corrigendum This article corrects the following: The effect of multiple simulation parameters on MM/PBSA performance for binding affinity prediction of CB1 cannabinoid receptor agonists and antagonists Jason S. E. Loo, Amelia Y. Y. Yong, Yen Nee Yong, Volume 96Issue 5Chemical Biology & Drug Design pages: 1244-1254 First Published online: June 25, 2020 First published: 10 May 2021 https://doi.org/10.1111/cbdd.13844AboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat The effect of multiple simulation parameters on MM/PBSA performance for binding affinity prediction of CB1 cannabinoid receptor agonists and antagonists. Chem Biol Drug Des. 2020;96:1244–1254. Jason S. E. Loo, Amelia Y. Y. Yong, Yen Nee Yong. The Abstract was incorrectly amended during proofing. The corrected Abstract is reproduced below. Both the inactive- and active-state CB1 receptor crystal structures have now been solved, allowing their application in various structure-based drug design methods. One potential method utilizing these crystal structures is the Molecular Mechanics/Poisson–Boltzmann Surface Area (MM/PBSA) method of predicting relative binding free energies. However, MM/PBSA performance is sensitive to various simulation parameters and often requires optimization for the system of interest. In this study, we evaluated the effects of various simulation parameters, namely simulation length, choice of dielectric constant, inclusion of explicit water molecules, and inclusion of entropy, on the ability of MM/PBSA to predict the experimental binding free energies of a set of known CB1 agonists and antagonists. MM/PBSA produced r values ranging from 0.410 to 0.688 for the CB1 agonists and from 0.420 to 0.678 for the CB1 antagonists depending on the simulation parameters, which were modestly better than correlations obtained using docking scores. Using fewer replicates with a longer simulation length and a higher solute dielectric constant value had the largest positive effect on performance. Including explicit water molecules at the protein–ligand interface had a minor positive effect on performance at higher dielectric constant values, while the inclusion of entropy had a detrimental effect across most of the dataset. REFERENCE Loo, JSE, Yong, AYY, & Yong, YN (2020). The effect of multiple simulation parameters on MM/PBSA performance for binding affinity prediction of CB1 cannabinoid receptor agonists and antagonists. Chem Biol Drug Des., 96: 1244– 1254. https://doi.org/10.1111/cbdd.13733Wiley Online LibraryCASPubMedWeb of Science®Google Scholar Volume97, Issue6June 2021Pages 1210-1210 ReferencesRelatedInformation

Lateral habenula cannabinoid CB1 receptor involvement in drug-associated impulsive behavior

Animal and human studies show that cannabis or its derivatives can increase relapse to cocaine seeking following withdrawal. Moreover, cannabis use in humans is associated with impulse control deficits and animal studies implicate endogenous cannabinoids (eCB) in several impulsivity constructs. However, the brain areas where cannabinoids might control impulsivity or cocaine seeking are largely unknown. Here, we assess Lateral Habenula (LHb) involvement on performance in the 5-choice serial reaction time task (5CSRTT) in rats and investigate whether LHb cannabinoid CB1 receptors (CB1R) are involved in these effects. Systemic cocaine increased premature responding, a measure of impulsivity, at a dose (5 mg/kg) that did not alter other measures of task performance. Intra-LHb infusion of the CB1R antagonist AM251 blocked this effect. Systemic injection of the psychoactive constituent of cannabis, Δ9-tetrahydrocannabinol (Δ9-THC, 1 mg/kg), also increased 5CSRTT premature responding at a dose that did not otherwise disrupt task performance. This was blocked by intra-LHb infusion of AM251 in a subgroup of rats showing the largest increases in Δ9-THC-evoked premature responses. Systemic Δ9-THC also prompted impulsive cocaine seeking in a Go/NoGo cocaine self-administration task and this was blocked by intra-LHb AM251. These data show that LHb CB1Rs are involved in deficits in impulse control initiated by cocaine and Δ9-THC, as assessed by the 5CSRTT, and play a role in impulsive cocaine seeking during cocaine self-administration. This suggests that the LHb eCB system contributes to the control of impulsive behavior, and thus represents a potential target for therapeutic treatment of substance use disorders (SUDs) in humans.

Beneficial Changes in Rat Vascular Endocannabinoid System in Primary Hypertension and under Treatment with Chronic Inhibition of Fatty Acid Amide Hydrolase by URB597.

Our study aimed to examine the effects of hypertension and the chronic administration of the fatty acid amide hydrolase (FAAH) inhibitor URB597 on vascular function and the endocannabinoid system in spontaneously hypertensive rats (SHR). Functional studies were performed on small mesenteric G3 arteries (sMA) and aortas isolated from SHR and normotensive Wistar Kyoto rats (WKY) treated with URB597 (1 mg/kg; twice daily for 14 days). In the aortas and sMA of SHR, endocannabinoid levels and cannabinoid CB1 receptor (CB1R) expression were elevated. The CB1R antagonist AM251 diminished the methanandamide-evoked relaxation only in the sMA of SHR and enhanced the vasoconstriction induced by phenylephrine and the thromboxane analog U46619 in sMA in SHR and WKY. In the sMA of SHR, URB597 elevated anandamide levels, improved the endothelium-dependent vasorelaxation to acetylcholine, and in the presence of AM251 reduced the vasoconstriction to phenylephrine and enhanced the vasodilatation to methanandamide, and tended to reduce hypertrophy. In the aortas, URB597 elevated endocannabinoid levels improved the endothelium-dependent vasorelaxation to acetylcholine and decreased CB1R expression. Our study showed that hypertension and chronic administration of URB597 caused local, resistance artery-specific beneficial alterations in the vascular endocannabinoid system, which may bring further advantages for therapeutic application of pharmacological inhibition of FAAH.