Pharmacological properties of the phytocannabinoids \u3949-tetrahydrocannabivarin and cannabidiol.

Cannabis and its derivatives have been used for medicinal purpose for thousand of years. More recently, the main cannabis constituents, cannabinoids, have been found to act and target at cannabinoid as well as other receptors. This brought particular interest around the pharmacology of phytocannabinoids and their possible clinical applications. The research object of this study focused on two phytocannabinoids, \u3949-tetrahydrocannabivarin (\u3949-THCV) and cannabidiol (CBD), and it has been divided in three individual investigations: In the first study, we investigated the pharmacology of \u3949-THCV at cannabinoid type 1 (CB1) and type 2 (CB2) receptors. We found and confirmed that \u3949-THCV acts as antagonist at CB1 receptors in experiments of [35S]GTP\u3b3S binding assay on human CB1-CHO (Chinese hamster ovary) cell membranes. Also, in the same set of experiments, \u3949-THCV displayed a slight inverse agonism at CB1 receptors, which was confirmed in experiments of cyclic AMP assay in hCB1-CHO cells. At CB2 receptors, we found that \u3949-THCV can behave as a partial agonist when the measured response is inhibition of forskolin-induced stimulation of cyclic AMP production in hCB2-CHO cells or stimulation of [35S]GTP\u3b3S binding to membranes obtained either from hCB2-CHO cells or from mouse spleen membranes. No such effect was displayed by \u3949-THCV in untransfected CHO cells, pertussis toxin (PTX)-treated hCB2-CHO cells or CB2 -/- mouse spleen membranes. In collaboration with Dr. Barbara Costa and Dr. Dino Maione, we also showed that \u3949-THCV shares the ability of established selective CB2 receptor agonist to reduce signs of inflammation and inflammatory pain (Guindon, Hohmann 2008). These experiments were performed on in vivo models of \u3bb-carrageenan-induced oedema and thermal hyperalgesia, and formalin-induced nociception. In the second investigation we brought further evidences that \u3949-THCV is a partial agonist at CB2 receptors. In detail, we applied a protocol to hCB2-CHO cells in order to convert the selective CB2 receptor antagonist/inverse agonist, AM630, into an apparent neutral antagonist. In these experimental conditions, we found that \u3949-THCV still behaves as a CB2 receptor agonist and is antagonized by AM630 in experiments of cyclic AMP assay. Additional tests were also conducted to better understand the pharmacology of the ligand, AM630, at CB2 receptors. In the third study, we investigated the effect of CBD at serotonin type 1A (5-HT1A) autoreceptors. This research was based on previous in vivo findings showing that CBD-induced anti-emetic and anti-nausea effects were mediated by somatodendritic 5-HT1A autoreceptors located in the raphe nuclei (Rock et al. 2009, Parker et al. 2010). Experiments of [35S]GTP\u3b3S binding conducted in rat brainstem membranes revealed that CBD, in a bell-shaped manner, is able to enhance the dose-response curve of the selective 5-HT1A receptor agonist, DPAT. In addition, our results suggest that CBD does not interact directly with 5-HT1A receptors, and that CBD-mediated DPAT dose-response curve enhancement might implicate the involvement of an other receptor

The pharmacology and function of receptors for short-chain fatty acids

Despite some blockbuster G protein–coupled receptor (GPCR) drugs, only a small fraction (∼15%) of the more than 390 nonodorant GPCRs have been successfully targeted by the pharmaceutical industry. One way that this issue might be addressed is via translation of recent deorphanization programs that have opened the prospect of extending the reach of new medicine design to novel receptor types with potential therapeutic value. Prominent among these receptors are those that respond to short-chain free fatty acids of carbon chain length 2–6. These receptors, FFA2 (GPR43) and FFA3 (GPR41), are each predominantly activated by the short-chain fatty acids acetate, propionate, and butyrate, ligands that originate largely as fermentation by-products of anaerobic bacteria in the gut. However, the presence of FFA2 and FFA3 on pancreatic β-cells, FFA3 on neurons, and FFA2 on leukocytes and adipocytes means that the biologic role of these receptors likely extends beyond the widely accepted role of regulating peptide hormone release from enteroendocrine cells in the gut. Here, we review the physiologic roles of FFA2 and FFA3, the recent development and use of receptor-selective pharmacological tool compounds and genetic models available to study these receptors, and present evidence of the potential therapeutic value of targeting this emerging receptor pair

Metabolic and inflammatory functions of short-chain fatty acid receptors

FFA2 and FFA3 are receptors for short-chain fatty acids which are produced in prodigious amounts by fermentation of poorly digested carbohydrates by gut bacteria. Understanding the roles of these receptors in regulating enteroendocrine, metabolic and immune functions has developed with the production and use of novel pharmacological tools and animal models. A complex (patho)physiological scenario is now emerging in which strategic expression of FFA2 and FFA3 in key cell types and selective modulation of their signalling might regulate body weight management, energy homoeostasis and inflammatory disorders

Towards Seismic Design of Nonstructural Elements: Italian Code-Compliant Acceleration Floor Response Spectra

Seismic risk reduction of a building system, meant as primary building structure and nonstructural elements (NSEs) as a whole, must rely upon an adequate design of each of these two items. As far as NSEs are concerned, adequate seismic design means understanding of some basic principles and concepts that involve different actors, such as designers, manufacturers, installers, and directors of works. The current Italian Building Code, referred to as NTC18 hereinafter, defines each set of tasks and responsibilities in a sufficiently detailed manner, rendering now evident that achieving the desired performance level stems from a jointed contribution of all actors involved. Bearing in mind that seismic design is nothing else than proportioning properly seismic demand, in terms of acceleration and/or displacement, and the corresponding capacity, this paper gives a synthetic and informative overview on how to evaluate these two parameters. To shed some light on this, the concept of acceleration floor response spectrum (AFRS) is firstly brought in, along with basics of building structure-NSEs interaction, and is then deepened by means of calculation methods. Both the most rigorous method based on nonlinear dynamic simulations and the simplified analytical formulations provided by the NTC18 are briefly discussed and reviewed, trying to make them clearer even to readers with no structural/earthquake engineering background because, as a matter of fact, NSEs are often selected by architects and/or mechanical or electrical engineers. Lastly, a simple case study, representative of a European code-compliant five-storey masonry-infilled reinforced concrete frame building, is presented to examine differences between numerical and analytical AFRS and to quantify accuracy of different NTC18 procedures

A single extracellular amino acid in Free Fatty Acid Receptor 2 defines antagonist species selectivity and G protein selection bias

Free Fatty Acid Receptor 2 is a GPCR activated by short chain fatty acids produced in high levels in the lower gut by microbial fermentation of non-digestible carbohydrates. A major challenge in studying this receptor is that the mouse ortholog does not have significant affinity for antagonists that are able to block the human receptor. Docking of exemplar antagonists from two chemical series to homology models of both human and mouse Free Fatty Acid Receptor 2 suggested that a single lysine - arginine variation at the extracellular face of the receptor might provide the basis for antagonist selectivity and mutational swap studies confirmed this hypothesis. Extending these studies to agonist function indicated that although the lysine - arginine variation between human and mouse orthologs had limited effect on G protein-mediated signal transduction, removal of positive charge from this residue produced a signalling-biased variant of Free Fatty Acid Receptor 2 in which Gi-mediated signalling by both short chain fatty acids and synthetic agonists was maintained whilst there was marked loss of agonist potency for signalling via Gq/11 and G12/13 G proteins. A single residue at the extracellular face of the receptor thus plays key roles in both agonist and antagonist function

Substance use and depression. Comparative course in adolescents

Objective: To examine the relation between depression and substance use in adolescents and the concomitant courses of both disorders. Methods: Four individual interviews were administered to 85 adolescent substance users aged 14-19 years (mean 17.1 years, SD 1.4) over a 3.5 year period using the Adolescent Drug Abuse Interview (ADAD) and the Beck Depression Inventory (BDI-13). Results: No predictive effect was observed on one dimension over the other, but each dimension was predictive of its own course. A decrease in substance-use severity paralleled a decrease in depressive state. Similarly, stable substance-use rates, either at a low or a high level, tended to be associated with low or high levels of depression, respectively. However, an increase in substance use was not accompanied by an increase in depressive states. Moreover, depression varied greatly between adolescents, and according to gender and age. Conclusions: Depressive states and substance use in adolescents can vary considerably overtime, and are closely but rather synchronically related. Since most of the adolescents do not seek help for substance-related problems, substance use should be systematically assessed in adolescents presenting with a depressive stat

Consequences of representativeness bias on SHM-based decision-making

Judging the state of a bridge based on SHM observations is an inference process, which should be rationally carried out using a logical approach. However, it is often observed that real-life decision makers depart from this ideal model of rationality, judge and decide using common sense, and privilege fast and frugal heuristics to rational analytic thinking. For instance, confusion between condition state and safety of a bridge is one of the most frequently observed examples in bridge management. The aim of this paper is to describe mathematically this observed biased judgement, a condition that is broadly described by Kahneman and Tversky’s representativeness heuristic. Particularly, the paper examines how this heuristic affects the interpretation of data, providing a deeper understanding of the differences between a method affected by cognitive biases and the classical rational approach. Based on the literature review, three different models reproducing an individual behaviour distorted by representativeness are identified. These models are applied to the case of a transportation manager who wrongly judges a particular bridge unsafe simply because deteriorated, regardless its actual residual load-carrying capacity. It is demonstrated that the application of any of the three heuristic judgment models correctly predicts that the manager will mistakenly judge the bridge as unsafe based on the observed condition state. It is not objective of the paper to suggest that representativeness should be used instead of rational logic, however, understanding how real-life managers actually behave is of paramount importance when setting a general policy for bridge maintenance

Adaptation of NS cells growth and differentiation to high-throughput screening-compatible plates

Peer reviewedPublisher PD

Evidence of top-down modulation of the Brentano illusion but not of the glare effect by transcranial direct current stimulation

Transcranial direct current stimulation (tDCS) has been widely used for modulating sensory, motor and cognitive functions, but there are only few attempts to induce and change illusory perception. Visual illusions have been the most traditional and effective way to investigate visual processing through the comparison between physical reality and subjective reports. Here we used tDCS to modulate two different visual illusions, namely the Brentano illusion and the glare effect, with the aim of uncovering the influence of top-down mechanisms on bottom-up visual perception in two experiments. In Experiment 1, to a first group of subjects, real and sham cathodal tDCS (2 mA, 10 min) were applied over the left and right posterior parietal cortices (PPC). In Experiment 2, real and sham cathodal tDCS were applied to the left and right occipital cortices (OC) to a second group of participants. Results showed that tDCS was effective in modulating only the Brentano illusion, but not the glare effect. tDCS increased the Brentano illusion but specifically for the stimulated cortical area (right PPC), illusion direction (leftward), visual hemispace (left), and illusion length (160 mm). These findings suggest the existence of an inhibitory modulation of top-down mechanisms on bottom-up visual processing specifically for the Brentano illusion, but not for the glare effect. The lack of effect of occipital tDCS should consider the possible role of ocular compensation or of the unstimulated hemisphere, which deserves further investigation