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  • 1
    Electronic Resource
    Electronic Resource
    Development and loss of tolerance to the effects of ethanol on DRL performance of rats (1989)
    Springer
    Psychopharmacology 97 (1989), S. 45-50 
    Details
    ISSN: 1432-2072
    Keywords: DRL ; Ethanol ; Operant behavior ; Rats ; Residual tolerance ; Tolerance ; Rate increases and decreases
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Six male Sprague-Dawley rats were trained on a DRL-20 operant schedule for food presentation. When stable performance was established, they were exposed to an escalating regimen of daily ethanol administration (1.125–3.75 g/kg. IP). This dosing regimen continued until the maximally tolerable dose for each subject was reached. Tolerance loss then was monitored for approximately 6 months by periodic ethanol challenge doses (1.5 g/kg). Dose-effect curves (DECs) were obtained prior to (DEC-1), immediately after (DEC-2), and 6 months following termination of (DEC-3) the ethanol exposure. Rate-increasing effects (DEC-1) were noted at low doses (0.75 and 1.125 g/kg), with a higher dose (2.25 g/kg) resulting in a decreased rate of responding. Tolerance, following chronic ethanol exposure, developed to both the rate-increasing and ratedecreasing effects of ethanol (DEC-2). While some tolerance was lost within the 6 months following the daily ethanol exposure (DEC-3), a significant degree of tolerance was still indicated by most of the response measures. This duration of tolerance was considerably longer than that generally reported, and is probably attributable to persistent learned compensatory behavior and/or intermittent ethanol challenge tests.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00443411
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  • 2
    Electronic Resource
    Electronic Resource
    Tolerance to ethanol's disruptive effects on operant behavior in rats (1989)
    Springer
    Psychopharmacology 99 (1989), S. 479-485 
    Details
    ISSN: 1432-2072
    Keywords: Ethanol ; Tolerance ; Operant performance ; Delayed ethanol effect ; Drug-induced compensatory learning
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effects of pre-session and post-session daily ethanol injections on the development and loss of tolerance to ethanol's effects on fixed ratio operant performance in rats was assessed using a cumulative dosing procedure. Daily pre-session ethanol administration produced a greater decrease in ethanol sensitivity than did daily post-session ethanol. Both tolerance effects persisted for at least 1 month after the chronic injection phase. No changes in ethanol sensitivity were apparent in the saline control group and no changes in estimated blood ethanol levels were found after the chronic treatments. The post-session ethanol groups displayed a performance decrement during the initial segment of the chronic injection period, but improved significantly across the chronic phase. These data suggest that some delayed effect of ethanol initially impaired performance but that tolerance to this ethanol effect also occurred and probably contributed to the decline in ethanol sensitivity seen in these groups. Compensatory learning as the mechanism for tolerance development in the pre-session and post-session ethanol groups was supported by the finding of no change in ethanol sensitivity in rats exposed to comparable daily ethanol without any concurrent operant task on which the direct, immediate, or indirect, delayed ethanol effects could operate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00589895
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  • 3
    Electronic Resource
    Electronic Resource
    Schedule-controlled behavior as an index of the development and loss of ethanol tolerance in the rat (1985)
    Springer
    Psychopharmacology 87 (1985), S. 414-420 
    Details
    ISSN: 1432-2072
    Keywords: Behavioral tolerance ; Ethanol ; Operant behavior ; Rats ; Residual tolerance ; Tolerance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Twelve male Sprague-Dawley rats, following training on one of two food-motivated operant schedules (Fixed-Ratio 30 or Variable Interval 30 s), were exposed to an escalating regimen of daily ethanol (1.125–3.0 g/kg, IP) administration. This increasing dose regimen continued until the maximally tolerable dose for each subject was reached. Tolerance was then monitored for approximately 6 months by periodic ethanol challenge doses (1.5 g/kg). Dose-effect curves (DECs) were obtained prior to chronic ethanol (DEC1), immediately after ethanol tolerance development (DEC2), and 6 months (DEC3) following termination of ethanol exposure. At DEC1, ethanol produced dose-dependent decreases in rate on both schedules with no significant schedule differences in ED50 (the dose effective at reducing the maximal response rate by one-half) values. Maximal tolerance was achieved in means of 46 and 55 days on the VI and FR schedules, respectively. Differences in rate of tolerance acquisition on the initial dose of the chronic regimen (1.125 g/kg) account for most of the difference in the overall rate of acquisition. Comparison of the ED50 data from DECs 1 and 2 indicated that daily ethanol exposure resulted in a 2-fold decrease in ethanol sensitivity (i.e., tolerance) on both operant schedules. The ED50 data from DECs 1 and 3 demonstrated a 1.7-fold decrease in ethanol potency on DEC3. This duration of tolerance was considerably longer than that generally reported, and possibly related to the extended ethanol exposure and the sensitivity of operant schedules to drug effects.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00432505
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  • 4
    Electronic Resource
    Electronic Resource
    State-dependent effects of ethanol on active and passive avoidance learning (1972)
    Springer
    Psychopharmacology 25 (1972), S. 238-261 
    Details
    ISSN: 1432-2072
    Keywords: Dissociation ; Ethanol ; Avoidance Conditioning ; Response-Initiation-Suppression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The present set of experiments examined the importance of the response initiation-inhibition parameter of certain avoidance conditioning tasks in the production of state-dependent dissociative effects with ethanol. On those tasks involving some degree of response inhibition (passive avoidance and two-way active avoidance), animals receiving ethanol during training were more impaired in their testing performance than those receiving saline during training (anterograde amnestic effect), and animals injected with ethanol during training and saline during testing displayed dissociation of their acquired avoidance behaviors during testing (asymmetrical dissociation effect). On the task involving a response initiation element with little contamination by response suppression factors (one-way active avoidance), dissociation of avoidance behavior during testing was found both for the animals trained under ethanol and tested under saline and for the animals trained under saline and tested under ethanol (symmetrical dissociation effect). The results were discussed in terms of possible joint effects of symmetrical state-dependency and other behavioral properties of the drug. However, an alternative interpretation could not be ruled out, namely that the mechanisms involved in the impairment found on the testing day for the drug-placebo and placebo-drug groups may be different. It was suggested that the drug-placebo group may represent the more general example of state-dependent dissociation effects, whereas the production of state-dependent dissociation effects in the placebo-drug group may depend upon the type of behavior conditioned and/or the strength of such conditioning.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00422505
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  • 5
    Electronic Resource
    Electronic Resource
    Factors governing the vulnerability of DRL operant performance to the effects of ethanol (1973)
    Springer
    Psychopharmacology 28 (1973), S. 351-362 
    Details
    ISSN: 1432-2072
    Keywords: Ethanol ; Operant Performance ; Dose-Response Analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effects of various doses of ethanol on DRL performance was examined in rats under conditions of cued and non-cued DRL tasks and under conditions of low versus high baseline performance criteria. The dose-level at which ethanol produced a significant reduction in number of responses and reinforcements interacted in a complex fashion with level of baseline performance, the cue conditions, and the order of DRL tasks. Generally, performance was impaired at a lower dose level for groups initially trained to a low criterion of DRL performance than for groups later trained to a higher criterion of DRL performance, regardless of cue condition. Further, the dose level at which ethanol impaired performance (as indicated by number of reinforcements obtained) under non-cued DRL conditions was lower than that for the cued DRL conditions, but only on the initial task where baseline DRL performance criterion was lower. Finally, the group with a higher baseline level of responding (i.e., poorer DRL performance) was more vulnerable to the disrupting effects of ethanol on this measure than groups with lower baseline response rates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00422755
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  • 6
    Electronic Resource
    Electronic Resource
    Tolerance to ethanol's effects on operant performance in rats: role of number and pattern of intoxicated practice opportunities (1992)
    Springer
    Psychopharmacology 109 (1992), S. 112-120 
    Details
    ISSN: 1432-2072
    Keywords: Ethanol ; Operant performance ; Tolerance ; Intoxicated practice ; Compensatory behaviors ; Acute ethanol withdrawal
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Acquisition and retention of tolerance to ethanol's rate-decreasing effects on operant performance were examined in rats which received a 52-day regimen of ethanol or saline injections prior to and/or after each daily session. Eight groups of rats differed on: (a) number of days with intoxicated practice (pre-session ethanol); (b) intermittent (spaced) or daily (massed) intoxicated practice; and (c) post-session ethanol or saline on nonintoxicated practice days. Massed practice groups were given their presession saline days prior to their pre-session ethanol days. Ethanol dose-effect tests were given prior to, during, and after the chronic injection regimen. Under both spaced and massed practice conditions, the magnitude of tolerance developed increased directly with the number of pre-session ethanol days, even when absolute ethanol exposure was constant. No group showed complete tolerance loss. The post-session ethanol supplements (a) facilitated tolerance development in spaced practice groups and tolerance loss in massed practice groups, (b) blocked ethanol's low dose rate-increasing effects, and (c) produced an acute withdrawal-like performance disruption the next day. The results suggest that both intoxicated practice and practice during acute ethanol withdrawal influence the acquisition and retention of compensatory behaviors during ethanol tolerance development.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02245488
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  • 7
    Electronic Resource
    Electronic Resource
    The effects of ferulic acid on the mineral nutrition of grain sorghum (1987)
    Springer
    Plant and soil 98 (1987), S. 99-109 
    Details
    ISSN: 1573-5036
    Keywords: Allelopathy ; Ferulic acid ; Magnesium ; Mineral content ; Phosphorus ; PotassiumSorghum bicolor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Two week old sorghum seedlings (Sorghum bicolor L. Moench) were treated with ferulic acid added to the nutrient solution. Effects on tissue concentration of P, K, Mg, Ca, Fe, and Zn were evaluated after 3 and 6 days. Treatemnts of 0.25 mM ferulic acid approximated the growth inhibition threshold, and after 6 days 0.5 mM treated plants weighed less than controls. Both treatments reduced the P content of the roots and shoots at the 3- and 6-day harvests in three replicate experiments. Roots of treated plants at both harvests had a lower concentration of K and Mg. These reductions in P, K, and Mg were most extensive from the 0.5 mM ferulic acid regime. In some cases at both harvests, shoot K was lower and Mg was higher than control tissue. Ferulic acid effects at the 3-day harvest included an elevation of Ca and depression of Fe in shoots. Changes in nutrient content preceded measurable differences in plant weight. These data indicate that one mechanism of growth inhibition by this allelochemical may be an alteration of nutrient balance.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02381731
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  • 8
    Electronic Resource
    Electronic Resource
    Bioassay of naturally occurring allelochemicals for phytotoxicity (1988)
    Springer
    Journal of chemical ecology 14 (1988), S. 1821-1828 
    Details
    ISSN: 1573-1561
    Keywords: Allelopathy ; bioassay ; mechanism of action ; seed germination ; radicle growth ; seedling growth ; Lemna bioassay
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The bioassay has been one of the most widely used tests to demonstrate allelopathic activity. Often, claims that a particular plant species inhibits the growth of another are based entirely on the seed germination response to solvent extracts of the suspected allelopathic plant; few of these tests are of value in demonstrating allelopathy under natural conditions. The veracity of the bioassay for evaluating naturally occurring compounds for phytotoxicity depends upon the physiological and biochemical response capacity of the bioassay organism and the mechanism(s) of action of the allelochemicals. The possibility that more than one allelochemical, acting in concert at very low concentrations, may be responsible for an observed allelopathic effect makes it imperative that bioassays be extremely sensitive to chemical growth perturbation agents. Among the many measures of phytotoxicity of allelochemicals, the inhibition (or stimulation) of seed germination, radicle elongation, and/or seedling growth have been the parameters of choice for most investigations. Few of these assays have been selected with the view towards the possible mechanism of the allelopathic effect.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01013479
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  • 9
    Electronic Resource
    Electronic Resource
    Prior cropping with grain sorghum inhibits weeds (1989)
    Springer
    Journal of chemical ecology 15 (1989), S. 951-960 
    Details
    ISSN: 1573-1561
    Keywords: Allelopathy ; grain sorghum ; Sorghum bicolor ; weed inhibition ; weed management
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Three years of field data in northeastern Nebraska demonstrate that a grain sorghum crop reduces weediness in the following crop year. Weed growth was consistently lower in sorghum areas the year after strip-cropping fields with sequences of four-row bands of grain sorghum, soybeans, and corn. Percentage weed cover was significantly lower early in the year, and midsummer weed biomass was well below that found after corn and soybeans. Weed biomass in June and July following corn was two to four times that of grain sorghum strips. Inhibitory effects of grain sorghum were primarily on broadleaf weeds, often showing no action on grass weeds. No obvious differences were noted in the weed species present after the three crops. Allelopathy provides a logical explanation for the sorghum-mediated weed inhibition found in this study. The data have implications for weed management strategies in agriculture.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01015190
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