1,721,040 research outputs found
Concurrent treatment with verapamil prevents diazepam withdrawapl-induced anxiety, in the absence of altered calcium flux in cortical synaptosomes
No full textRats, chronically treated with diazepam (4 mg/kg/day) for 28 days, displayed increased anxiety when tested in the elevated plus-maze, 42 hr after the last dose. This anxiogenic withdrawal response was entirely prevented by the concurrent administration of the calcium channel antagonist, verapamil. No anxiolytic effect of chronic administration of verapamil was observed in vehicle-treated rats. To investigate the possibility that increased calcium function in nerve terminals might underlie diazepam withdrawal-induced anxiety, the uptake by cortical synaptosomes of 45Ca2 + was studied. Both fast (3-sec) and slow (60-sec) phase uptake were measured. No changes in basal (5 mM), potassium-stimulated (55 mM) or net uptake were observed during either fast or slow phase uptake. It is concluded that increased calcium influx in nerve terminals in the cortex does not underlie the anxiogenic effect of withdrawal of the benzodiazepine but that further studies must be carried out in other regions of the brai
Evidence that the increased anxiety detected in the elevated plus-maze during chlordiazepoxide withdrawal is not due to enhanced noradrenergic activity
No full textRats displayed a reduction in the percentage of time spent on the open arms of the elevated plus-maze 24-30 hours after withdrawal from chronic chlordiazepoxide treatment (10 mg/kg/day IP for 4 weeks). This indicated an anxiogenic response in this test. This anxiogenic response was not significantly reversed by DL-propranolol (5 and 10 mg/kg IP) or clonidine (0.02 and 0.04 mg/kg IP). These results provide no evidence to suggest that the anxiogenic effects of chlordiazepoxide withdrawal are mediated by an increase in noradrenergic activity. The possible involvement of multiple transmitter systems in benzodiazepine withdrawal symptomology is discussed. © 1989
Flumazenil but not nitrendipine reverses the increased anxiety during ethanol withdrawal in the rat
No full textAfter 7 day's gradual introduction of ethanol, rats were maintained for a further 4 weeks on a liquid diet containing 10% ethanol (mean daily dose 11.8±0.2 g/kg/day). Control-treated rats received liquid diet alone. Pairs of rats were tested in the social interaction test of anxiety 8 h after withdrawal. Withdrawal from ethanol significantly reduced the time spent in social interaction compared with controls, indicating an anxiogenic withdrawal response. Nitrendipine (50 mg/kg) had no effect on, whereas flumazenil (4 mg/kg) significantly reversed, this withdrawal response. This reversal appeared to be long-lasting as there was still no evidence of increased anxiety when rats were again withdrawn after 3 more days of ethanol diet. © 1989 Springer-Verlag
Characterisation of the phenomenon of "one-trial tolerance" to the anxiolytic effect of chlordiazepoxide in the elevated plus-maze
No full textIn the elevated plus-maze test of anxiety the scores of control animals remain stable over repeated tests. However, a single prior exposure to the plus-maze renders an animal insensitive to the anxiolytic effects of chlordiazepoxide. This phenomenon of "one-trial tolerance" persisted even when the two trials were separated by as much as 2 weeks. It has previously been shown that the drug state of the animal on trial 1 is not important to the development of the phenomenon, but one-trial tolerance did not develop if a very high dose (75 mg/kg) of chlordiazepoxide was given on trial 1; it is suggested that this is due to the amnesic effects of the drug. The learning on trial 1 was not specific to a particular plus-maze and tolerance could be observed even when the maze on trial 1 was made from different material. The crucial experience on trial 1 was experience of an open arm of the maze. Whereas tolerance could be obtained as a result of a previous plus-maze experience, there was no evidence of an anxiogenic withdrawal response when rats were tested the following day undrugged. The phenomenon of one-trial tolerance is explained within our recently proposed two-factor theory of benzodiazepine dependence; it is suggested that one-trial tolerance provides a method for studying the mechanism underlying the development of tolerance to anxiolytic effects, independently from the mechanism underlying the development of withdrawal responses. © 1990 Springer-Verlag
Chronic diazepam treatment in rats causes long-lasting changes in central [3H]-5-hydroxytryptamine and [14C]-y-aminobutyric acid release
No full textThe effects of chronic diazepam administration to rats on the central release of [3H]-5-hydroxytryptamine ([3H]-5-HT) and [14C]-y-aminobutyric acid (["4C]-GABA, ex vivo) were examined. Chronic (5 and 21 days) administration of diazepam (4mgkg-1 i.p. daily for 21 days) reduced the K-evoked (20mm KCI) release of [3H]-5-HT from frontal cortex by approximately 50%. Remarkably, this decrease was still present 1 week after diazepam withdrawal. Chronic diazepam treatment did not significantly affect hippocampal [3H]-5-HT release but after 21 days the K-evoked release of [14C]-GABA was more than doubled and remained elevated 30h after withdrawal; it returned to control levels after 1 week, and decreased below control levels after 2 weeks. This study indicates that chronic diazepam treatment produces striking changes in transmitter release in rats that persist long after treatment has ceased
The use of flumazenil in prevention of Diazepam dependence in the rat
No full textRats were treated with diazepam (4 mg/kg per day) or its vehicle for 21 days. Twentyâfour hours after their last dose they were tested in the social interaction test of anxiety. Diazepam withdrawal significantly reduced the time spent in social interaction compared with controls, indicating an anxiogenic withdrawal response. The administration of a single dose of flumazenil (4 mg/kg) during chronic diazepam treatment, 7 or 14 days before testing, prevented the development of this withdrawal response. The clinical implications of these findings are discussed. Copyright © 1990 John Wiley & Sons, Ltd
Nicotine self-administration and withdrawal: modulation of anxiety in the social interaction test in rats.
No full textRATIONALE: Most smokers report smoking has an anxiolytic effect, which may contribute to nicotine dependence. OBJECTIVE: To examine effects in the social interaction test (SI) of anxiety after 4 weeks' self-administered nicotine (15 infusions of 0.03 mg/kg, totalling 0.45 mg/kg per day), and after 24 and 72 h of withdrawal. The effect of exposure to the operant chamber on withdrawal responses was also examined. METHODS: Animals were trained to self-administer saline or nicotine and after 4 weeks they were tested in SI after their daily self-administration session. Animals were retested after 24 and 72 h withdrawal, when they were either taken directly from the home cage or were tested 5 min after a 30-min exposure to the operant chamber. RESULTS: Compared with the saline control group, the animals that had been self-administering nicotine for 4 weeks showed decreased social interaction with no decrease in locomotor activity, indicating a significant anxiogenic effect of the nicotine infusions. There was no change in social interaction after 24 and 72 h withdrawal from chronic nicotine, regardless of whether or not the rats were exposed to the operant chamber just prior to being tested. CONCLUSIONS: Nicotine self-administration is not maintained because of its anxiolytic effect, but despite, or because of, its anxiogenic effect. There was no evidence of an anxiogenic response after either 24 or 72 h of withdrawal and thus increased anxiety on withdrawal from nicotine does not seem to contribute to nicotine self-administration
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
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