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  • 1
    Electronic Resource
    Electronic Resource
    The effects of feeding conditions on drug-reinforced behavior: Maintenance at reduced body weight versus availability of food (1980)
    Springer
    Psychopharmacology 68 (1980), S. 121-124 
    Details
    ISSN: 1432-2072
    Keywords: Etonitazene reinforcement ; Oral selfadministration ; Food deprivation ; Food access ; Concurrent schedules ; Rats
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Recent research has shown that food deprivation increases drug self-administration in rats and rhesus monkeys. The purpose of the present study was to examine two variables related to this food-deprivation effect: maintenance of rats at reduced body weights and the absence of food. Etonitazene HCl was established as a reinforcer orally for 12 rats according to procedures previously used in experiments reported by this laboratory. Lever-pressing behavior was maintained under fixed-ratio (FR) schedules during daily 1-h sessions by etonitazene or water, which were available either concurrently or on alternating days. In the first experiment, six rats were maintained at 75% of their free-feeding weights. The effect of presenting the daily food allotment at 23, 4, 2, 1, or 0 h before their daily drug or water self-administration session was studied. When the rats were fed 23, 4, or 2 h before the session, etonitazene dipper presentations were at maximum levels and were substantially higher than for water. When the rats were fed during (0) or 1 h before the session, the number of etonitazene dipper presentations was lower, but it exceeded those for water. Under conditions of complete food satiation (0 h deprived-100% body weight), etonitazene and water dipper presentations were both low, and there were no differences between them. In the second experiment, six rats maintained at 75% of their free-feeding weights were trained to respond for etonitazene or water on alternating days. When they were subsequently food satiated (100% body weight), drug- and water-maintained behavior decreased to low levels. These rats were then deprived of food for 4 or 16 h before their daily 1-h session, and responding did not increase. Body weight did not decrease below 100%. These results suggest that maintenance at reduced body weight rather than the absence of food is the determinant of increased rates of drug-reinforced behavior.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00432128
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  • 2
    Electronic Resource
    Electronic Resource
    Determinants of increased drug self-administration due to food deprivation (1981)
    Springer
    Psychopharmacology 74 (1981), S. 197-200 
    Details
    ISSN: 1432-2072
    Keywords: Drug self-administration ; Food deprivation ; Etonitazene ; Rats
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Changes in oral etonitazene self-administration were compared in four groups of rats that were maintained at 100, 95, 85, or 75% of their pre-experimental free-feeding body weights. Etonitazene (5 μg/ml) or water was available for 16 h according to a fixed-ratio (FR) 1 schedule. Each liquid delivery (0.1 ml) was contingent upon a lever-press response. During food deprivation etonitazene intake gradually increased to over two-fold as body weights decreased over 25 sessions; etonitazene intake was inversely proportional to body weight. The 75% weight group showed stereotypy, self-mutilation and large variability in daily etonitazene intake. In another experiment a range of deprivation conditions was studied in a group of six rats with etonitazene (5 μg/ml) or water available on an FR 8 schedule during 1-h sessions. When the rats were gradually food satiated, etonitazene-maintained behavior declined but remained higher than water-maintained behavior; however, when they were abruptly food satiated, etonitazene-maintained behavior decreased to low levels.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00427092
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  • 3
    Electronic Resource
    Electronic Resource
    An evaluation of the selectivity of fenmetozole (DH-524) reversal of ethanol-induced changes in central nervous system function (1980)
    Springer
    Psychopharmacology 69 (1980), S. 149-155 
    Details
    ISSN: 1432-2072
    Keywords: Fenmetozole ; Ethanol ; Aerial righting reflex ; Conflict behavior ; Guanosine 3′,5′-monophosphate ; Physical dependence ; Physiological antagonism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The selectivity and specificity of fenmetozole (DH-524) [2(3,4-dichlorophenoxy-methy))2-imidazole HCl] as an antagonist of the actions of ethanol were examined. Fenmetozole (15–30 g/kg) reduced ethanol-induced impairment of the aerial righting reflex without changing blood or brain ethanol content, indicating that the antagonistic actions of fenmetozole were not due to change in the pharmacokinetics of ethanol. Since fenmetozole also reduced aerial righting reflex impairment due to phenobarbital, chlordiazepoxide, and halothane, this action of fenmetozole was not specific to ethanol. In mice, both the ethanolinduced increase in locomotor activity at 2.0 g/kg and the decrease caused by 4.0 g/kg were antagonized by fenmetozole. In addition, fenmetozole attenuated the ethanol-induced reduction in cerebellar cyclic guanosine monophosphate (cGMP) content, but the drug also significantly elevated cGMP levels in this tissue when given alone. Fenmetozole did not alter ethanolinduced increases in punished drinking in a conflict test, except at a high dose which alone decreased both punished and unpunished responding. Fenmetozole also failed to precipitate ethanol withdrawal-like reactions when given to physically-dependent, intoxicated rats. Thus, the antagonistic action of fenmetozole against ethanol would not seem to be related to a specific receptor interaction but rather may be the result of a physiological antagonism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00427641
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  • 4
    Electronic Resource
    Electronic Resource
    Differential patterns of phytoalexin accumulation and enzyme induction in wounded and elicitor-treated tissues ofPhaseolus vulgaris (1982)
    Springer
    Planta 154 (1982), S. 156-164 
    Details
    ISSN: 1432-2048
    Keywords: Chalcone synthase ; Colletotrichum ; Elicitor ; Phaseolus ; Phenylalanine ammonia-lyase ; Phytoalexin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In wounded cotyledons ofPhaseolus vulgaris L. the accumulation of the 5-hydroxy isoflavonoids kievitone and 2′-hydroxygenistein precedes the major increases in the levels of the 5-deoxy compounds phaseollin and coumestrol. Increased phytoalexin levels are preceded by transient increases in the extractable activities of L-phenylalanine ammonia-lyase (EC 4.3.1.5.), chalcone synthase and chalcone isomerase (EC 5.5.1.6.). Accumulation of phytoalexins, above wounded control levels, is observed following treatment of excised cotyledons or hypocotyls with crude or fractionated elicitor preparations heat-released from the cell walls ofColletotrichum lindemuthianum. Chalcone synthase levels are also induced in cotyledons, although crude elicitor and all fractions suppress L-phenylalanine ammonia-lyase activity in both tissues. Kievitone is the major phytoalexin induced in cotyledons, whereas in hypocotyls phaseollin predominates. Patterns of phytoalexin accumulation have been studied in response to varying concentrations of the crude and fractionated elicitor; 5-hydroxy isoflavonoid accumulation is highly dependent upon elicitor concentration, the dose-response curves for kievitone accumulation showing maxima at around 1 μg glucose equivalents per cotyledon, minima at 2–3 μg equivalents and increasing induction at higher concentrations. Similar patterns are observed for L-phenylalanine ammonia-lyase and chalcone synthase levels, although the overall extent of these changes is masked by the high wound response. Accumulation of 5-deoxy isoflavonoids above control levels requires high elicitor concentrations; no experimental conditions were found under which phaseollin accumulated to higher levels than kievitone in cotyledons during the first 48 h after elicitation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00387910
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  • 5
    Electronic Resource
    Electronic Resource
    Elicitor-mediated induction of chalcone isomerase in Phaseolus vulgaris cell suspension cultures (1983)
    Springer
    Planta 159 (1983), S. 561-569 
    Details
    ISSN: 1432-2048
    Keywords: Cell suspension culture ; Chalcone isomerase ; Elicitor ; Enzyme induction ; Phaseolus (chalcone isomerase) ; Phytoalexin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Approximately fourfold increases in the extractable activity of the enzyme chalcone isomerase (CHI, EC 5.5.1.6) were observed within 24 h of treatment of cell suspension cultures of Phaseolus vulgaris with a crude elicitor preparation heatreleased from the cell walls of the bean pathogen Colletotrichum lindemuthianum. The induction of CHI activity was highly dependent upon elicitor concentration, with maximum induction occurring in two discrete concentration ranges. A basal half-life for CHI〉32 h in control cultures was determined by labelling with 2H from 2H2O followed by analysis of the equilibrium distribution of enzyme activity in CsCl density gradients. Comparative density labelling indicated that at both the lower and higher effective elicitor concentrations, the induced appearance of CHI activity was the result of an apparent initial activation of pre-existing enzyme followed by an increase in the rate of de-novo synthesis of the enzyme as compared with non-elicited controls. The increased appearance of the enzyme over the first 8 h in elicitor-treated cultures was inhibited by cycloheximide, cordycepin and actinomycin D. The results are discussed in relation to the mechanisms of co-ordinate enzyme induction operating in French-bean cell cultures exposed to fungal elicitors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00409146
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