Cannabinoid-1 receptor inverse agonists: current understanding of mechanism of action and unanswered questions

Unraveling the Endocannabinoid System: Exploring Its Therapeutic Potential in Autism Spectrum Disorder

The salient features of autism spectrum disorder (ASD) encompass persistent difficulties in social communication, as well as the presence of restricted and repetitive facets of behavior, hobbies, or pursuits, which are often accompanied with cognitive limitations. Over the past few decades, a sizable number of studies have been conducted to enhance our understanding of the pathophysiology of ASD. Preclinical rat models have proven to be extremely valuable in simulating and analyzing the roles of a wide range of established environmental and genetic factors. Recent research has also demonstrated the significant involvement of the endocannabinoid system (ECS) in the pathogenesis of several neuropsychiatric diseases, including ASD. In fact, the ECS has the potential to regulate a multitude of metabolic and cellular pathways associated with autism, including the immune system. Moreover, the ECS has emerged as a promising target for intervention with high predictive validity. Particularly noteworthy are resent preclinical studies in rodents, which describe the onset of ASD-like symptoms after various genetic or pharmacological interventions targeting the ECS, providing encouraging evidence for further exploration in this area.

Alterations in plasma endocannabinoid concentrations among individuals with major depression treated with electroconvulsive therapy

The role of the endocannabinoid system (ECS) in depression and suicidality has recently emerged. The purpose of the study was to identify changes in plasma endocannabinoid concentrations of several endocannabinoids and correlate them with depressive symptoms and suicidality in patients with severe major depression undergoing electroconvulsive therapy (ECT). The study included 17 patients that were evaluated in four visits at different stages of therapy. At each visit depression, anxiety and suicidality symptoms were assessed and blood samples collected. Several endocannabinoid concentrations increased following six sessions of ECT, as 2-AG (p < 0.05) and LEA (p < 0.01), and following twelve sessions of ECT, as 2-AG (p < 0.05), AEA (p < 0.05), LEA (p < 0.05) and DH-Gly (p < 0.05). Endocannabinoids also correlated with symptoms of depression, anxiety and suicidality at baseline and at the sixth ECT session. Finally, we found one endocannabinoid, l-Gly, that differentiated between remitted and not-remitted patients at the seventh and thirteenth ECT sessions (p < 0.05). Our findings suggest that depression is markedly related to imbalance of the endocannabinoid system, and further regulated by ECT. Plasma endocannabinoids could be promising biomarkers for detection of depression response and remission.

Novel pharmacological interventions for diabetic kidney disease

PURPOSE OF REVIEW

The purpose of this review is to summarize the latest evidence on the prevention and progression of diabetic kidney disease (DKD), as well as novel pharmacological interventions from preclinical and early clinical studies with promising findings in the reduction of this condition's burden.

RECENT FINDINGS

We will cover the latest evidence on the reduction of proteinuria and kidney function decline in DKD achieved through established renin-angiotensin-aldosterone system (RAAS) system blockade and the more recent addition of SGLT2i, nonsteroidal mineralocorticoid receptor antagonists (MRAs) and GLP1-RA, that combined will most likely integrate the mainstay for current DKD treatment. We also highlight evidence from new mechanisms of action in DKD, including other haemodynamic anti-inflammatory and antifibrotic interventions, oxidative stress modulators and cell identity and epigenetic targets.

SUMMARY

Renal specific outcome trials have become more popular and are increasing the available armamentarium to diminish the progression of renal decline in patients at greater risk of end-stage kidney disease (ESKD) such as diabetic individuals. A combined pharmaceutical approach based on available rigorous studies should include RAAS blockade, SGLT2 inhibitors, nonsteroidal MRA and expectedly GLP1-RA on a personalized based-intervention. New specific trials designed to address renal outcomes will be needed for innovative therapies to conclude on their potential benefits in DKD.

Chemistry, Crystal Structure, and In Vitro Receptor Binding of Δ10-THC Isomers

Introduction: The psychoactive properties of Δ10-THC isomers (trans- and cis-Δ10-THC) are poorly understood. To shed more light on the biological effects of these compounds, we studied in vitro receptor binding of Δ10-THC isomers at cannabinoid CB1 and CB2 receptors. Materials and Methods: We first optimized and simplified catalytic synthesis of trans- and cis-Δ10-THC to allow their safe and cheap large-scale synthesis. In our synthesis, BuLi was replaced with KOtBu, and DMSO/anisole or NEt3/heptane solvent systems were used instead of HMPA/toluene. Single crystal X-ray analysis confirmed the structure of both isomers and the configuration of their chiral centers. Results: In the radioligand replacement assay, both isomers showed strong affinity toward the CB1 receptor, with IC50=29.1 nM for the trans isomer and IC50=294.2 nM for the cis counterpart. However, the IC50 values were significantly higher than that of Δ9-THC (2.1 nM), a naturally occurring psychoactive component of cannabis sativa, suggesting a lower affinity of Δ10-THCs toward this receptor. In function assays, in contrast to Δ9-THC, both isomers failed to show any agonist properties at concentrations up to 10 μM suggesting a lack of THC-like psychoactivity for trans- and cis-Δ10-THC. Conclusions: Our results established Δ10-THC isomers among antagonists of the CB1 receptor as both cis and trans isomers antagonized CP55,490 with IC50=460 nM for trans and IC50=1040 nM for cis. This functional property has not been previously observed for any other THC isomers.

Potential Repurposed Drug Candidates for Tuberculosis Treatment: Progress and Update of Drugs Identified in Over a Decade

The devastating impact of Tuberculosis (TB) has been a menace to mankind for decades. The World Health Organization (WHO) End TB Strategy aims to reduce TB mortality up to 95% and 90% of overall TB cases worldwide, by 2035. This incessant urge will be achieved with a breakthrough in either a new TB vaccine or novel drugs with higher efficacy. However, the development of novel drugs is a laborious process involving a timeline of almost 20-30 years with huge expenditure; on the other hand, repurposing previously approved drugs is a viable technique for overcoming current bottlenecks in the identification of new anti-TB agents. The present comprehensive review discusses the progress of almost all the repurposed drugs that have been identified to the present day (∼100) and are in the development or clinical testing phase against TB. We have also emphasized the efficacy of repurposed drugs in combination with already available frontline anti-TB medications along with the scope of future investigations. This study would provide the researchers a detailed overview of nearly all identified anti-TB repurposed drugs and may assist them in selecting the lead compounds for further in vivo/clinical research.

A peripherally restricted cannabinoid-1 receptor inverse agonist promotes insulin secretion and protects from cytokine toxicity in human pancreatic islets

The cannabinoid receptor CB1R is expressed in pancreatic β-cells; CB1R increased activity is associated with diabetes, obesity, cardiovascular disorders as well as decreased insulin secretion and insulin resistance. CB1R was shown to signal through G-protein coupling as well as β-arrestins in β-cells. Peripherally restricted CB1R inverse agonists purportedly have beneficial effects on insulin secretion in β-cells, without the unwanted effects in the central nervous system. Here we show that a peripherally restricted CB1R inverse agonist, MRI-1891, augments glucose stimulated insulin secretion in isolated human pancreatic islets and mouse islets. The insulin secretion enhancing effect of MRI-1891 is comparable to exendin-4, an analogue of the glucagon like peptide-1 (GLP1). Moreover, MRI-1891 treatment protects isolated human islet cells against cytokine-induced apoptosis, similar to exendin-4. Thus, MRI-1891, a new class of CB1R inverse agonist, may be considered a potential therapeutic for both type 1 and type 2 diabetes because of its ability to protect pancreatic β-cells from cytokine toxicity and to promote insulin secretion.

Pharmacological selection of cannabinoid receptor effectors: Signalling, allosteric modulation and bias

The type-1 cannabinoid receptor (CB₁) is a promising drug target for a wide range of diseases. However, many existing and novel candidate ligands for CB₁ have shown only limited therapeutic potential. Indeed, no ligands are currently approved for the clinic except formulations of the phytocannabinoids Δ⁹-THC and CBD and a small number of analogues. A key limitation of many promising CB₁ ligands are their on-target adverse effects, notably including psychoactivity (agonists) and depression/suicidal ideation (inverse agonists). Recent drug development attempts have therefore focussed on altering CB₁ signalling profiles in two ways. Firstly, with compounds that enhance or reduce the signalling of endogenous (endo-) cannabinoids, namely allosteric modulators. Secondly, with compounds that probe the capability of selectively targeting specific cellular signalling pathways that may mediate therapeutic effects using biased ligands. This review will summarise the current paradigm of CB₁ signalling in terms of the intracellular transduction pathways acted on by the receptor. The development of compounds that selectively activate CB₁ signalling pathways, whether allosterically or via orthosteric agonist bias, will also be addressed.

CH-Diazomethane Sulfonamides Generated in Situ for Intramolecular [3+2] Cycloaddition of Alkynes: An Entry into Novel Pyrazole-Fused Five-Membered Sultams

Previously reported CH-diazomethane sulfonamides carrying various propargylic groups are generated in situ from their acetyl precursors. Without purification, these compounds undergo a slow, albeit clean and efficient, intramolecular [3+2] cycloaddition to give pyrazole-fused five-membered sultams. The latter are the first analogues of medicinally important (hetero)arene-fused five-membered sultams containing a five-membered nitrogenous heterocycle. The newly introduced scaffold can be further elaborated into N-arylated derivatives using the Chan–Evans–Lam protocol. The resulting compounds incorporate more than one privileged moiety and are highly suitable for interrogation of protein targets via biological screening.

Repurposed drug candidates for antituberculosis therapy

Antibiotics have been a key part of clinical treatments for more than 70 years. Long-term use of antimicrobial treatments has led to the development of severe bacterial resistance, which has become increasingly serious due to antibiotic abuse, resulting in the treatment of bacterial infections becoming challenging. The repurposing of approved drugs presents a promising strategy to address current bottlenecks in the development of novel antibacterial agents. Drug repurposing is a cost-effective emerging strategy, which aims to treat resistant infectious diseases by identifying known drugs with predicted efficacy for diseases other than the target disease. This strategy has potential in the treatment of tuberculosis (TB), particularly drug-resistant TB. In recent years, a panel of drugs approved for clinical use or clinical trials, such as linezolid, vancomycin and celecoxib, have been found to have anti-TB activities. However, the utility of drug repurposing is limited by the number of candidate compounds and their low activities. The low activities of repurposed drugs have slowed the development of a drug-repurposing strategy for anti-TB drugs. The present review discusses progress in the discovery of new anti-TB agents through drug repurposing since 2014. We also discuss the challenges faced and analyze the innovative ways that are being used to overcome these difficulties. This review may provide a useful guide for researchers in the field of drug repurposing.

Probing the CB1 Cannabinoid Receptor Binding Pocket with AM6538, a High-Affinity Irreversible Antagonist

Cannabinoid receptor 1 (CB₁) is a potential therapeutic target for the treatment of pain, obesity and obesity-related metabolic disorders, and addiction. The crystal structure of human CB₁ has been determined in complex with the stabilizing antagonist AM6538. In the present study, we characterize AM6538 as a tight-binding/irreversible antagonist of CB₁, as well as two derivatives of AM6538 (AM4112 and AM6542) as slowly dissociating CB₁ antagonists across binding simulations and cellular signaling assays. The long-lasting nature of AM6538 was explored in vivo wherein AM6538 continues to block CP55,940-mediated behaviors in mice up to 5 days after a single injection. In contrast, the effects of SR141716A abate in mice 2 days after injection. These studies demonstrate the functional outcome of CB₁ antagonist modification and open the path for development of long-lasting CB₁ antagonists.

Innovative Therapeutic Potential of Cannabinoid Receptors as Targets in Alzheimer’s Disease and Less Well-Known Diseases

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The discovery of cannabinoid receptors at the beginning of the 1990s, CB1 cloned in 1990 and CB2 cloned in 1993, and the availability of selective and potent cannabimimetics could only be justified by the existence of endogenous ligands that are capable of binding to them. Thus, the characterisation and cloning of the first cannabinoid receptor (CB1) led to the isolation and characterisation of the first endocannabinoid, arachidonoylethanolamide (AEA), two years later and the subsequent identification of a family of lipid transmitters known as the fatty acid ester 2-arachidonoylglycerol (2-AG).

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The endogenous cannabinoid system is a complex signalling system that comprises transmembrane endocannabinoid receptors, their endogenous ligands (the endocannabinoids), the specific uptake mechanisms and the enzymatic systems related to their biosynthesis and degradation.

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The endocannabinoid system has been implicated in a wide diversity of biological processes, in both the central and peripheral nervous systems, including memory, learning, neuronal development, stress and emotions, food intake, energy regulation, peripheral metabolism, and the regulation of hormonal balance through the endocrine system.

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In this context, this article will review the current knowledge of the therapeutic potential of cannabinoid receptor as a target in Alzheimer’s disease and other less well-known diseases that include, among others, multiple sclerosis, bone metabolism, and Fragile X syndrome.

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The therapeutic applications will be addressed through the study of cannabinoid agonists acting as single drugs and multi-target drugs highlighting the CB2 receptor agonist.

Antagonism of Cannabinoid Receptor 1 Attenuates the Anti-Inflammatory Effects of Electroacupuncture in a Rodent Model of Migraine

Background

The anti-nociceptive effects of electroacupuncture (EA) in migraine have been documented in multiple randomised controlled trials. Neurogenic inflammation plays a key role in migraine attacks, and the anti-inflammatory effects of acupuncture have been associated with the type 1 cannabinoid (CB1) receptor.

Objective

To investigate whether CB1 receptors mediate the anti-inflammatory effects of EA on migraine attacks.

Methods

A migraine model was produced in Sprague-Dawley rats by unilateral electrical stimulation of the trigeminal ganglion (TGES). Rats received EA daily on the 5 days preceding TGES with (TGES+EA+SR141716 group) or without (TGES+EA group) intraperitoneal injections of the CB1 receptor antagonist SR141716. Another group of TGES rats (TGES+MA group) and a non-TGES sham-operated group of rats (Sham+MA group) received minimal acupuncture (MA). Calcitonin gene-related peptide (CGRP) and prostaglandin E2 (PGE2) concentrations were determined in serum obtained from the ipsilateral jugular vein at initiation of TGES and 5 min after. Postmortem interleukin (IL)-1β and cyclooxygenase (COX)2 protein levels in the trigeminal ganglion (TG) and plasma protein extravasation (PPE) in the dura mater were assessed.

Results

TGES induced increases in serum CGRP and PGE2 levels (TGES+MA vs baseline and vs Sham: all p<0.001), as well as IL-1β and COX2 protein expression in the TG, and neurogenic PPE levels (TGES+MA vs Sham+MA: all p<0.001). EA attenuated TGES-induced increases in the levels of these proteins (TGES+EA vs TGES+MA: all p<0.001). CB1 receptor antagonism reversed the effects of EA (TGES+EA+SR141716 vs TGES+EA: all p<0.05).

Conclusions

CB1 receptors appear to mediate anti-inflammatory effects of EA in a rat model of migraine.

Pharmacological interventions for obesity: current and future targets

PURPOSE OF REVIEW

Obesity in the United States has been on a constant rise since the Center for Disease Control and Prevention (CDC) began tracking it over 50 years ago. Despite focused attention on this epidemic, pharmacological treatments aimed at obesity are lacking. Here, we briefly give perspective on the central and peripheral mechanisms underlying feeding behaviors and describe the existing pharmacological treatments for obesity. With this lens, I suggest future targets for the treatment of obesity.

RECENT FINDINGS

Given the development of genetic and molecular tools, understanding of how energy expenditure is modulated is becoming more nuanced. There is growing evidence for a link between obesity and addiction, which should be utilized in the development of new pharmacological treatments.

SUMMARY

More focus is needed on identifying targets for anti-obesity pharmacology. In doing so, research should include intensive investigation of the brain's reward circuitry.

Novel derivatives of 1,2,3-triazole, cannabinoid-1 receptor ligands modulate gastrointestinal motility in mice

Cannabinoid-1 (CB1) receptors are broadly distributed in the central and peripheral nervous systems; among others, they are located in the enteric nervous system. In the gastrointestinal (GI) system, they participate in regulation of intestinal motility or ion transport. The aim of our study was to assess the effect of 1,2,3-triazole derivatives (compound 1: 2-[4,5-bis(2,4-dichlorophenyl)-2H-1,2,3-triazol-2-yl]-N-(2-fluorobenzyl)acetamide, compound 2: 2-[4,5-bis(2,4-dichlorophenyl)-2H-1,2,3-triazol-2-yl]-N-(4-fluorobenzyl)acetamide, compound 3: N-benzyl-2-[4-(4-chlorophenyl)-5-(2,4-dichlorophenyl)-2H-1,2,3-triazol-2-yl]acetamide]), characterized in vitro as CB1 antagonists with high CB1 over CB2 selectivity, in the mouse GI tract. The action of compounds 1-3 was assessed in vitro (electrical field stimulated smooth muscle contractility of the mouse ileum and colon) and in vivo (whole GI transit time). Compound 1 decreased ileal (10^-6 M) and colonic (10^-7-10^-6 M) smooth muscles contractility. Moreover, it prolonged whole GI transit. Compound 2 (10^-10-10^-8 M) slightly increased the amplitude of muscle contractions in the ileum, but at a higher concentration (10^-6 M), the amplitude was decreased. Compound 2 reduced colonic contractility but accelerated GI transit. Compound 3 decreased the amplitude of intestinal muscle contractions in the ileum (10^-6 M) and colon (10^-10-10^-6 M). Moreover, it increased the GI transit time in vivo. Triazole derivatives possess easily modifiable structure and interesting pharmacological action in the GI tract; further, alterations may enhance their efficacy at CB receptors and provide low side effect profile in clinical conditions.

The Therapeutic Aspects of the Endocannabinoid System (ECS) for Cancer and their Development: From Nature to Laboratory

The endocannabinoid system (ECS) is a group of neuromodulatory lipids and their receptors, which are widely distributed in mammalian tissues. ECS regulates various cardiovascular, nervous, and immune system functions inside cells. In recent years, there has been a growing body of evidence for the use of synthetic and natural cannabinoids as potential anticancer agents. For instance, the CB1 and CB2 receptors are assumed to play an important role inside the endocannabinoid system. These receptors are abundantly expressed in the brain and fatty tissue of the human body. Despite recent developments in molecular biology, there is still a lack of knowledge about the distribution of CB1 and CB2 receptors in the human kidney and their role in kidney cancer. To address this gap, we explore and demonstrate the role of the endocannabinoid system in renal cell carcinoma (RCC). In this brief overview, we elucidate the therapeutic aspects of the endocannabinoid system for various cancers and explain how this system can be used for treating kidney cancer. Overall, this review provides new insights into cannabinoids' mechanisms of action in both in vivo and in vitro models, and focuses on recent discoveries in the field.

Ethyl 4,6-dimethyl-3-oxo-2-phenyl-3,7-dihydro-2H-pyrazolo[3,4-b]pyridine-5-carboxylate monohydrate

In the title compound, C17H17N3O3·H2O, the dihedral angle between the 4,6-dimethyl-pyrazolo[3,4-b]pyridine-3-one unit [maximum deviation = 0.048 (2) Å] and the phenyl ring is 5.1 (1)°. The structure is characterized by disorder of the carboxylate O atoms, which are split into two parts with a major component of 0.898 (4). In the crystal, the organic molecules and lattice water molecules are linked via O—H...O, O—H...N and N—H...O hydrogen bonds. The molecules are also linked by C—H...π and weak offset π–π stacking interactions, forming sheets parallel to (001).

Synthesis of Pyrazole-Thiobarbituric Acid Derivatives: Antimicrobial Activity and Docking Studies

A one-pot reaction was described that results in various pyrazole-thiobarbituric acid derivatives as new pharmacophore agents. These new heterocycles were synthesized in high yields with a broad substrate scope under mild reaction conditions in water mediated by NHEt₂. The molecular structures of the synthesized compounds were assigned based on different spectroscopic techniques. The new compounds were evaluated for their antibacterial and antifungal activity. Compounds 4h and 4l were the most active compounds against C. albicans with MIC = 4 µg/L. Compound 4c exhibited the best activity against S. aureus and E. faecalis with MIC = 16 µg/L. However, compounds 4l and 4o were the most active against B. subtilis with MIC = 16 µg/L. Molecular docking studies for the final compounds and standard drugs were performed using the OpenEye program.

Genetic Versus Pharmacological Assessment of the Role of Cannabinoid Type 2 Receptors in Alcohol Reward-Related Behaviors

BACKGROUND

Emerging evidence suggests that the endocannabinoid system (ECS) is involved in modulating the rewarding effects of abused drugs. Recently, the cannabinoid receptor 2 (CB2R) was shown to be expressed in brain reward circuitry and is implicated in modulating the rewarding effects of alcohol.

METHODS

CB2 ligands and CB2R knockout (KO) mice were used to assess CB2R involvement in alcohol reward-related behavior in 2 well-established behavioral models: limited-access 2-bottle choice drinking and conditioned place preference (CPP). For the pharmacological studies, mice received pretreatments of either vehicle, the CB2R agonist JWH-133 (10 and 20 mg/kg) or the CB2R antagonist AM630 (10 and 20 mg/kg) 30 minutes before behavioral testing. For the genetic studies, CB2R KO mice were compared to wild-type (WT) littermate controls.

RESULTS

CB2R KO mice displayed increased magnitude of alcohol-induced CPP compared to WT mice. Neither agonism nor antagonism of CB2R affected alcohol intake or the expression of CPP, and antagonism of CB2R during CPP acquisition trials also did not affect CPP.

CONCLUSIONS

The CB2R KO CPP data provide partial support for the hypothesis that CB2Rs are involved in the modulation of alcohol reward-related behaviors. However, pharmacological manipulation of CB2Rs did not alter alcohol's rewarding effects in the alcohol-seeking models used here. These results highlight the importance of pharmacological validation of effects seen with lifetime KO models. Given the ongoing efforts toward medications development, future studies should continue to explore the role of the CB2R as a potential neurobiological target for the treatment of alcohol use disorders.

Design, synthesis, topoisomerase I & II inhibitory activity, antiproliferative activity, and structure-activity relationship study of pyrazoline derivatives: An ATP-competitive human topoisomerase IIα catalytic inhibitor

A series of pyrazoline derivatives (5) were synthesized in 92-96% yields from chalcones (3) and hydrazides (4). Subsequently, topo-I and IIα-mediated relaxation and antiproliferative activity assays were evaluated for 5. Among the tested compounds, 5h had a very strong topo-I activity of 97% (Camptothecin, 74%) at concentration of 100 μM. Nevertheless, all the compounds 5a-5i showed significant topo II inhibitory activity in the range of 90-94% (Etoposide, 96%) at the same concentration. Cytotoxic potential of these compounds was tested in a panel of three human tumor cell lines, HCT15, BT474 and T47D. All the compounds showed strong activity against HCT15 cell line with IC50 at the range of 1.9-10.4 μM (Adriamycin, 23.0; Etoposide, 6.9; and Camptothecin, 7.1 μM). Moreover, compounds 5c, 5f and 5i were observed to have strong antiproliferative activity against BT474 cell lines. Since, compound 5d showed antiproliferative activity at a very low IC50 thus 5d was then selected to study on their mode of action with diverse methods of ATP competition assay, ATPase assay and DNA-topo IIα cleavable complex assay and the results revealed that it functioned as a ATP-competitive human topoisomerase IIα catalytic inhibitor. Further evaluation of endogenous topo-mediated DNA relaxation in cells has been conducted to find that, 5d inhibited endogenous topo-mediated pBR322 plasmid relaxation is more efficient (78.0 ± 4.7% at 50 μM) than Etoposide (36.0 ± 1.7% at 50 μM).

Cannabinoids: Medical implications

Herbal cannabis has been used for thousands of years for medical purposes. With elucidation of the chemical structures of tetrahydrocannabinol (THC) and cannabidiol (CBD) and with discovery of the human endocannabinoid system, the medical usefulness of cannabinoids has been more intensively explored. While more randomized clinical trials are needed for some medical conditions, other medical disorders, like chronic cancer and neuropathic pain and certain symptoms of multiple sclerosis, have substantial evidence supporting cannabinoid efficacy. While herbal cannabis has not met rigorous FDA standards for medical approval, specific well-characterized cannabinoids have met those standards. Where medical cannabis is legal, patients typically see a physician who "certifies" that a benefit may result. Physicians must consider important patient selection criteria such as failure of standard medical treatment for a debilitating medical disorder. Medical cannabis patients must be informed about potential adverse effects, such as acute impairment of memory, coordination and judgment, and possible chronic effects, such as cannabis use disorder, cognitive impairment, and chronic bronchitis. In addition, social dysfunction may result at work/school, and there is increased possibility of motor vehicle accidents. Novel ways to manipulate the endocannbinoid system are being explored to maximize benefits of cannabinoid therapy and lessen possible harmful effects.

Pattern Recognition in Pharmacodynamic Data Analysis

Pattern recognition is a key element in pharmacodynamic analyses as a first step to identify drug action and selection of a pharmacodynamic model. The essence of this process is going from data to insight through exploratory data analysis. There are few formal strategies that scientists typically use when the experiment has been done and data collected. This report attempts to ameliorate this deficit by identifying the properties of a pharmacodynamic model via dissection of the pattern revealed in response-time data. Pattern recognition in pharmacodynamic analyses contrasts with pharmacokinetic analyses with respect to time course. Thus, the time course of drug in plasma usually differs markedly from the time course of the biomarker response, as a consequence of a myriad of interactions (transport to biophase, binding to target, activation of target and downstream mediators, physiological response, cascade and amplification of biosignals, homeostatic feedback) between the events of exposure to test compound and the occurrence of the biomarker response. Homing in on this important-but less often addressed-element, 20 datasets of varying complexity were analyzed, and from this, we summarize a set of points to consider, specifically addressing baseline behavior, number of phases in the response-time course, time delays between concentration- and response-time courses, peak shifts in response with increasing doses, saturation, and other potential nonlinearities. These strategies will hopefully give a better understanding of the complete pharmacodynamic response-time profile.

Microwave-assisted one-pot synthesis and antimicrobial evaluation of 2-(1-phenyl-3-(2-thienyl)-1H-pyrazol-4-yl)chroman-4-one derivatives

New hybrid compounds containing flavanone and pyrazoline motifs were synthesized by microwave irradiation and conventional heating methods using one-pot synthetic strategy. The products were evaluated for their antimicrobial activity.

A review of pharmacogenetic studies of substance-related disorders

BACKGROUND

Substance-related disorders (SRDs) are a major cause of morbidity and mortality worldwide. Family, twin, and adoption studies have demonstrated the substantial heritability of SRDs. To determine the impact of genetic variation on risk for SRD and the response to treatment, researchers have conducted a number of secondary data analyses and quasi-experimental studies that target one or more candidate gene variants.

METHODS

This review examines studies in which candidate polymorphisms were examined as mediator variables to identify pharmacogenetic effects on subjective responses to drug administration or cues or outcomes of medication trials for SRDs. Efforts to use a meta-analytic approach to quantify these effects are premature because the number of available studies using similar methods and outcomes is limited, so the present review is qualitative.

RESULTS

Findings from these studies provide preliminary evidence of clinically relevant pharmacogenetic effects. However, independent replication of these findings has been sparse.

CONCLUSIONS

Although this growing body of literature has produced conflicting results, improved statistical controls may help to clarify the findings. Additionally, the use of empirically derived sub-phenotypes (i.e., which serve to differentiate distinct groups of affected individuals) may also help to identify genetic mediators of pharmacologic response in relation to SRDs. The identification of genetic mediators can inform clinical care both by identifying risk factors for SRDs and predicting adverse events and therapeutic outcomes associated with specific pharmacotherapies.

A cannabinoid receptor agonist N-arachidonoyl dopamine inhibits adipocyte differentiation in human mesenchymal stem cells

Endocannabinoids can affect multiple cellular targets, such as cannabinoid (CB) receptors, transient receptor potential cation channel, subfamily V, member 1 (TRPV1) and peroxisome proliferator-activated receptor γ (PPARγ). The stimuli to induce adipocyte differentiation in hBM-MSCs increase the gene transcription of the CB₁ receptor, TRPV1 and PPARγ. In this study, the effects of three endocannabinoids, N-arachidonoyl ethanolamine (AEA), N-arachidonoyl dopamine (NADA) and 2-arachidonoyl glycerol (2-AG), on adipogenesis in hBM-MSCs were evaluated. The adipocyte differentiation was promoted by AEA whereas inhibited by NADA. No change was observed by the treatment of non-cytotoxic concentrations of 2-AG. The difference between AEA and NADA in the regulation of adipogenesis is associated with their effects on PPARγ transactivation. AEA can directly activate PPARγ. The effect of AEA on PPARγ in hBM-MSCs may prevail over that on the CB₁ receptor mediated signal transduction, giving rise to the AEA-induced promotion of adipogenesis. In contrast, NADA had no effect on the PPARγ activity in the PPARγ transactivation assay. The inhibitory effect of NADA on adipogenesis in hBM-MSCs was reversed not by capsazepine, a TRPV1 antagonist, but by rimonabant, a CB₁ antagonist/inverse agonist. Rimonabant by itself promoted adipogenesis in hBM-MSCs, which may be interpreted as the result of the inverse agonism of the CB₁ receptor. This result suggests that the constantly active CB₁ receptor may contribute to suppress the adipocyte differentiation of hBM-MSCs. Therefore, the selective CB₁ agonists that are unable to affect cellular PPARγ activity inhibit adipogenesis in hBM-MSCs.

A PET study comparing receptor occupancy by five selective cannabinoid 1 receptor antagonists in non-human primates

There is a medical need for safe and efficacious anti-obesity drugs with acceptable side effect profiles. To mitigate the challenge posed by translating target interaction across species and balancing beneficial vs. adverse effects, a positron emission tomography (PET) approach could help guide clinical dose optimization. Thus, as part of a compound differentiation effort, three novel selective CB1 receptor (CB1R) antagonists, developed by AstraZeneca (AZ) for the treatment of obesity, were compared with two clinically tested reference compounds, rimonabant and taranabant, with regard to receptor occupancy relative to dose and exposure. A total of 42 PET measurements were performed in 6 non-human primates using the novel CB1R antagonist radioligand [(11)C]SD5024. The AZ CB1R antagonists bound in a saturable manner to brain CB1R with in vivo affinities similar to that of rimonabant and taranabant, compounds with proven weight loss efficacy in clinical trials. Interestingly, it was found that exposures corresponding to those needed for optimal clinical efficacy of rimonabant and taranabant resulted in a CB1R occupancy typically around ∼20-30%, thus much lower than what would be expected for classical G-protein coupled receptor (GPCR) antagonists in other therapeutic contexts. These findings are also discussed in relation to emerging literature on the potential usefulness of 'neutral' vs. 'classical' CB1R (inverse agonist) antagonists. The study additionally highlighted the usefulness of the radioligand [(11)C]SD5024 as a specific tracer for CB1R in the primate brain, though an arterial input function would ideally be required in future studies to further assure accurate quantitative analysis of specific binding.

Constitutive activity in cannabinoid receptors

The cannabinoid receptors are G protein-coupled receptors activated by endocannabinoids or exogenous agonist such as tetrahydrocannabinol. Upon agonist binding, cannabinoid receptors will activate G proteins of the Gi family, which in turn inhibits adenylyl cyclase. Recently, inverse agonists and neutral antagonist for cannabinoid receptors have been discovered, demonstrating constitutive activity of the cannabinoid receptors. This chapter will discuss the current state of the art and provide a framework for evaluating constitutive receptor activity and distinguishing constitutive receptor activity from constitutive endogenous agonist tone.

The corrosion inhibition effect of aryl pyrazolo pyridines on copper in hydrochloric acid system: computational and electrochemical studies

The inhibition effect of three aryl pyrazole pyridine derivatives (APPs) against the corrosion of copper in 0.5 M HCl has been investigated by electrochemical impedance, potentiodynamic polarization measurements and quantum chemical methods.

Synthesis and biological evaluation of novel chiral diazepine derivatives as bombesin receptor subtype-3 (BRS-3) agonists incorporating an antedrug approach

Novel compounds based on the lead BRS-3 agonists from our HTS compounds 2a and 2b have been synthesized with the focus on obtaining peripheral BRS-3 agonists. To identify potent anti-obesity compounds without adverse effects on the central nerve system, a labile carboxylic ester with an antedrug functionality was introduced onto the terminal position. Through the extensive synthetic exploration and the pharmacokinetic studies of oral administration in mice, the phenol ester 17c was selected due to the most suitable pharmacological profile. In the evaluation of food intake suppression in B6 mice, 17c showed significant in vivo efficacy and no clear adverse effect on heart rate and blood pressure change in dog iv infusion. Our study paved the way for development of anti-diabetes and obesity drugs with a safer profile.

Effects of the novel cannabinoid CB1 receptor antagonist PF 514273 on the acquisition and expression of ethanol conditioned place preference

The centrally expressed cannabinoid receptor (CB1) has been considered a potential therapeutic target in treating alcoholism. Though CB1 receptors have been shown to modulate primary and conditioned ethanol reward, much of this research employed animal models that require ethanol ingestion or oral routes of administration. This is problematic considering CB1 antagonist drugs have high anorectic liability and have been used clinically in the treatment of obesity. Therefore, the present study examined CB1 antagonism in DBA/2J mice using an unbiased ethanol-induced conditioned place preference (CPP) procedure, a paradigm that does not require ethanol ingestion. To evaluate the role of CB1 receptors in primary ethanol reward, the highly potent and selective novel CB1 antagonist 2-(2-chlorophenyl)-3-(4-chlorophenyl)-7-(2,2-difluoropropyl)-6,7-dihydro-2H-pyrazolo[3,4-f][1,4]oxazepin-8(5H)-one (PF 514273) was administered 30 min before place preference conditioning with a fixed dose of ethanol (acquisition). To evaluate the role of CB1 receptors in ethanol-conditioned reward, PF 514273 was administered 30 min before place preference testing (expression). Although PF 514273 reduced ethanol-stimulated and basal locomotor activity, it did not perturb the acquisition or expression of ethanol-induced CPP. Results from the present study appear inconsistent with other studies that have demonstrated a role for CB1 antagonism in ethanol reward using oral administration paradigms. Our findings suggest that CB1 antagonism may have greater involvement in consummatory behavior than ethanol reward.

High-fat and obesogenic diets: current and future strategies to fight obesity and diabetes

Obesity, diabetes and their associated diseases are some of the greatest challenges that the world health care systems already face and with prospects of overburdening their capacities and funding. Due to decreased energetic expenditure and increased caloric intake, particularly in saturated fats, the number of people afflicted by said conditions is increasing by the day. Due to the failure, to this day, to effectively and ubiquity prevent and revert these diseases, the research into new compounds and therapeutic strategies is vital. In this review, we explain the most common dietary models of obesity and diabetes and the novel avenues of research we believe will be taken in the next few years in obesity and diabetes research. We primarily focus on the role of mitochondria and how the modulation of mitochondrial function and number as well as several promising therapeutic strategies involving metabolic regulators can positively affect the obese and diabetic status.

CART in the brain of vertebrates: circuits, functions and evolution

Cocaine- and amphetamine-regulated transcript peptide (CART) with its wide distribution in the brain of mammals has been the focus of considerable research in recent years. Last two decades have witnessed a steady rise in the information on the genes that encode this neuropeptide and regulation of its transcription and translation. CART is highly enriched in the hypothalamic nuclei and its relevance to energy homeostasis and neuroendocrine control has been understood in great details. However, the occurrence of this peptide in a range of diverse circuitries for sensory, motor, vegetative, limbic and higher cortical areas has been confounding. Evidence that CART peptide may have role in addiction, pain, reward, learning and memory, cognition, sleep, reproduction and development, modulation of behavior and regulation of autonomic nervous system are accumulating, but an integration has been missing. A steady stream of papers has been pointing at the therapeutic potentials of CART. The current review is an attempt at piecing together the fragments of available information, and seeks meaning out of the CART elements in their anatomical niche. We try to put together the CART containing neuronal circuitries that have been conclusively demonstrated as well as those which have been proposed, but need confirmation. With a view to finding out the evolutionary antecedents, we visit the CART systems in sub-mammalian vertebrates and seek the answer why the system is shaped the way it is. We enquire into the conservation of the CART system and appreciate its functional diversity across the phyla.

Novel Pharmacologic Approaches to Treating Cannabis Use Disorder

With large and increasing numbers of people using cannabis, the development of cannabis use disorder (CUD) is a growing public health concern. Despite the success of evidence-based psychosocial therapies, low rates of initial abstinence and high rates of relapse during and following treatment for CUD suggest a need for adjunct pharmacotherapies. Here we review the literature on medication development for the treatment of CUD, with a particular focus on studies published within the last three years (2010-2013). Studies in both the human laboratory and in the clinic have tested medications with a wide variety of mechanisms. In the laboratory, the following medication strategies have been shown to decrease cannabis withdrawal and self-administration following a period of abstinence (a model of relapse): the cannabinoid receptor agonist, nabilone, and the adrenergic agonist, lofexidine, alone and in combination with dronabinol (synthetic THC), supporting clinical testing of these medication strategies. Antidepressant, anxiolytic and antipsychotic drugs targeting monoamines (norepinephrine, dopamine, and serotonin) have generally failed to decrease withdrawal symptoms or laboratory measures of relapse. In terms of clinical trials, dronabinol and multiple antidepressants (fluoxetine, venlafaxine and buspirone) have failed to decrease cannabis use. Preliminary results from controlled clinical trials with gabapentin and N-acetylcysteine (NAC) support further research on these medication strategies. Data from open label and laboratory studies suggest lithium and oxytocin also warrant further testing. Overall, it is likely that different medications will be needed to target distinct aspects of problematic cannabis use: craving, ongoing use, withdrawal and relapse. Continued research is needed in preclinical, laboratory and clinical settings.

Functionally Optimized Neuritogenic Farinosone C Analogs: SAR-Study and Investigations on Their Mode of Action

Several natural products derived from entomopathogenic fungi have been shown to initiate neuronal differentiation in the rat pheochromocytoma PC12 cell line. After the successful completion of the total synthesis program, the reduction of structural complexity while retaining biological activity was targeted. In this study, farinosone C served as a lead structure and inspired the preparation of small molecules with reduced complexity, of which several were able to induce neurite outgrowth. This allowed for the elaboration of a detailed structure-activity relationship. Investigations on the mode of action utilizing a computational similarity ensemble approach suggested the involvement of the endocannabinoid system as potential target for our analogs and also led to the discovery of four potent new endocannabinoid transport inhibitors.

Endocannabinoid receptor deficiency affects maternal care and alters the dam's hippocampal oxytocin receptor and brain-derived neurotrophic factor expression

Maternal care is the newborn's first experience of social interaction, and this influences infant survival, development and social competences throughout life. We recently found that postpartum blocking of the endocannabinoid receptor-1 (CB1R) altered maternal behaviour. In the present study, maternal care was assessed by the time taken to retrieve pups, pups' ultrasonic vocalisations (USVs) and pup body weight, comparing CB1R deleted (CB1R KO) versus wild-type (WT) mice. After culling on postpartum day 8, hippocampal expression of oxytocin receptor (OXTR), brain-derived neurotrophic factor (BDNF) and stress-mediating factors were evaluated in CB1R KO and WT dams. Comparisons were also performed with nulliparous (NP) CB1R KO and WT mice. Compared to WT, CB1R KO dams were slower to retrieve their pups. Although the body weight of the KO pups did not differ from the weight of WT pups, they emitted fewer USVs. This impairment of the dam-pup relationship correlated with a significant reduction of OXTR mRNA and protein levels among CB1R KO dams compared to WT dams. Furthermore, WT dams exhibited elevated OXTR mRNA expression, as well as increased levels of mineralocorticoid and glucocorticoid receptors, compared to WT NP mice. By contrast, CB1R KO dams showed no such elevation of OXTR expression, alongside lower BDNF and mineralocorticoid receptors, as well as elevated corticotrophin-releasing hormone mRNA levels, when compared to CB1R KO NP. Thus, it appears that the disruption of endocannabinoid signalling by CB1R deletion alters expression of the OXTR, apparently leading to deleterious effects upon maternal behaviour.