1,720,964 research outputs found
Stress-induced activation of ventral tegmental mu-opioid receptors reduces accumbens dopamine tone by enhancing dopamine transmission in the medial pre-frontal cortex
No full textRationale Endogenous opioids could play a major role in the mesocorticolimbic dopamine (DA) responses to stress challenge. However, there is still no direct evidence of an influence of endogenous opioids on any of these responses. Objective We assessed whether and how endogenous opioids modulate fluctuations of mesocortical and mesoaccumbens DA tone in rats during a first experience with restraint stress. Method We first evaluated the effects of systemic naltrexone (NTRX) on DA outflow in the medial prefrontal cortex (mpFC) and in the nucleus accumbens (NAc) through dual-probe microdialysis. Second, we assessed the effect of perfusion, through reverse microdialysis, of direct DA receptor agonists in mpFC on NAc DA outflow in NTRX-pretreated stressed rats. Finally, we tested the effects of ventral tegmental area (VTA) perfusion of NTRX, the selective mu1 antagonist naloxonazine and the selective delta antagonist naltrindole on mpFC and NAc DA outflow in stressed rats, with multiple probe experiments. Results Systemic NTRX, at behaviorally effective doses, selectively prevented the increase of mpFC DA levels and the reduction of NAc DA levels observable during prolonged restraint. Local co-perfusion of D1 and D2 agonists in mpFC recovered inhibition of NAc DA in NTRX-pretreated restrained rats. Finally, intra-VTA perfusion of either NTRX or the mu1 antagonist, but not the delta antagonist, mimicked the effects of systemic NTRX. Conclusion During prolonged experience with a novel unavoidable/uncontrollable stressor, endogenous opioids, through stimulation of mu1 receptors in the VTA, elevate mesocortical DA tone thus reducing DA tone in the NAc DA. © 2014 Springer-Verlag Berlin Heidelberg
Interaction Between Genetic And Environmental Factors Promotes Eating Disorders Altering Expression And Function Of Dopamine, Serotonin And Norepinephrine Receptors
No full textEating disorders are multifactorial conditions involving genetic, metabolic, environmental, and behavioral factors. Although animal studies cannot reproduce the complex psychosomatic features of human eating disorders, can be useful to separately examine the elements of the homeostatic and motivational impairments associated with compulsive eating behaviors.
Drugs of abuse and palatable food intake show behavioral similarities and common neurobiological adaptations have been proposed to be involved in both drug and food related-disorders (Volkow and Wise, 2005). Compulsive drug intake in the face of adverse consequences is a hallmark feature of addiction and compulsive drug seeking has been shown to emerge only following an extended history of drug-taking (Vanderschuren and Everitt, 2004). Similarly, compulsive eating emerges following extended access to a palatable diet (Johnson and Kenny, 2010). Finally, stress exposure influences both the propensity to take drugs and food intake.
Dopamine is a neurotransmitter critically involved in the reward and motivational aspects of feeding and D2 receptors have received particular attention (Wang et al., 2001; Davis et al 2009). However, recent reviews have focused on central monoamine systems in eating disorders, such serotonin and norepinephrine (Hainer et al , 2006; Kaye, 2008).
Here we show that interaction between extended access to chocolate and chronic stress is able to transform adaptive food seeking/intake behavior into compulsive eating in DBA/2J mice (previously shown by Patel and coworkers, 2006, to be characterized by high impulsivity), but not in C57BL/6J mice.
Moreover, we find strong alterations of dopamine, serotonin and norepinephrine receptors expression in three brain areas (medial prefrontal cortex, nucleus accumbens, dorsal striatum) critically involved in food-related motivated behavior.
The animal model proposed here could be a good tool for understanding how environmental factors interact with genetic vulnerability to promote the development of eating disorders altering expression and function of dopamine, serotonin and norepinephrine receptors
NS.2.4 - SOCIAL ISOLATION EPISODES DURING PERI-ADOLESCENCE INDUCE DEPRESSION-LIKE PHENOTYPE AND EPIGENETIC MODIFICATIONS COMMON TO BRAIN AND BLOOD IN ADULT MICE
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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
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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