1,721,005 research outputs found
RIEDEL G. EFFECT OF Δ9-THC AND CBD-RICH CANNABIS EXTRACTS ON LATENT LEARNING IN RATS
No full textM3 Receptor Pathway Stimulates Rapid Transcription of the CB1 Receptor Activation through Calcium Signalling and the CNR1 Gene Promoter
No full textIn this study, we have investigated a possible mechanism that enables CB1/M3 receptor cross-talk, using SH-SY5Y cells as a model system. Our results show that M3 receptor activation initiates signaling that rapidly upregulates the CNR1 gene, resulting in a greatly potentiated CB1 receptor response to agonists. Calcium homeostasis plays an essential intermediary role in this functional CB1/M3 receptor cross-talk. We show that M3 receptor-triggered calcium release greatly increases CB1 receptor expression via both transcriptional and translational activity, by enhancing CNR1 promoter activity. The co-expression of M3 and CB1 receptors in brain areas such as the nucleus accumbens and amygdala support the hypothesis that the altered synaptic plasticity observed after exposure to cannabinoids involves cross-talk with the M3 receptor subtype. In this context, M3 receptors and their interaction with the cannabinoid system at the transcriptional level represent a potential pharmacogenomic target not only for the develop of new drugs for addressing addiction and tolerance. but also to understand the mechanisms underpinning response stratification to cannabinoids
In vitro and in vivo pharmacological characterization of two novel selective cannabinoid CB2 receptor inverse agonists
No full textWe have previously developed quinolone-3-carboxamides with the aim of obtaining new ligands for both cannabinoid receptors, CB1 and CB2. Our preliminary screening led to the identification of cannabinoid receptor ligands characterized by high affinity and, in some cases, also selectivity for CB2 receptors. Specifically, three compounds, 1,2 and 3 showed high affinity for CB2 as well as high selectivity over CB1 receptors. In addition, the activity shown by 1 against the formalin-induced nocifensive response in mice, reported in our previous paper, suggests that quinolone-3-carboxamides possess anti-nociceptive properties. In the present work, we have performed functional in vitro bioassays with the aim of investigating the functional activity in the [S-35]GTF gamma S binding assay of the other two compounds that, like 1, behave as CB2 selective ligands, and their potential analgesic actions in vivo. We found that both 2 and 3 behave in vitro as CB2 inverse agonists and are able to decrease nociceptive behaviour in the late phase of the formalin test only at the highest dose tested, although, at lower doses, they prevent the anti-nociceptive effects of a selective CB2 partial agonist in the formalin test. These results identify in 2 and 3 two novel, potent and selective CB2 antagonists/inverse agonists and confirm previous reports in the literature that, in addition to agonists at cannabinoid CB2 receptors, also inverse agonists/antagonists at these receptors show promise as anti-inflammatory agents. (C) 2009 Elsevier Ltd. All rights reserved
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Effect of cannabis on glutamate signalling in the brain: A systematic review of human and animal evidence
Full text linkUse of cannabis or delta-9-tetrahydrocannabinol (Delta 9-THC), its main psychoactive ingredient, is associated with psychotic symptoms or disorder. However, the neurochemical mechanism that may underlie this psychotomimetic effect is poorly understood. Although dopaminergic dysfunction is generally recognized as the final common pathway in psychosis, evidence of the effects of Delta 9-THC or cannabis use on dopaminergic measures in the brain is equivocal. In fact, it is thought that cannabis or Delta 9-THC may not act on dopamine firing directly but indirectly by altering glutamate neurotransmission. Here we systematically review all studies examining acute and chronic effects of cannabis or Delta 9-THC on glutamate signalling in both animals and man. Limited research carried out in humans tends to support the evidence that chronic cannabis use reduces levels of glutamate-derived metabolites in both cortical and subcortical brain areas. Research in animals tends to consistently suggest that Delta 9-THC depresses glutamate synaptic transmission via CB1 receptor activation, affecting glutamate release, inhibiting receptors and transporters function, reducing enzyme activity, and disrupting glutamate synaptic plasticity after prolonged exposure. (C) 2016 Elsevier Ltd. All rights reserved
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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