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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Psychopharmacology 97 (1989), S. 45-50 
    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
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  • 2
    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
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  • 3
    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
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Psychopharmacology 25 (1972), S. 238-261 
    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
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Psychopharmacology 28 (1973), S. 351-362 
    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
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  • 6
    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
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  • 7
    ISSN: 0173-0835
    Keywords: Two-dimensional nonequilibrium pH gradient gel electrophoresis ; Rat kidney ; Polyacrylamide gel electrophoresis ; Lead exposure ; Glutathione S-transferase ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Glutathione S-transferases (GST) are a family of detoxification isoenzymes that catalyze the conjugation of xenobiotics and their metabolites with reduced glutathione. Lead exposure in rats is known to induce GST isoenzymes in the liver and kidney. These changes in expression have potential use as biomarkers of lead exposure. Because two-dimensional electrophoresis (2-DE) enables one to analyze both protein abundance changes and chemical changes in protein structure, 2-DE was used to determine the effect of in vivo lead exposure on GST isoform expression in rat kidney cytosols. Male Sprague-Dawley rats were exposed to inorganic lead, and proteins were separated by conventional ISO-DALT and NEPHGE-DALT techniques and blotted for immunological identification. Lead exposure caused detectable inductions in both GSTP1 and GSTM1 and quantifiable charge modification in GSTP1. These preliminary data confirm the utility of 2-D electrophoretic GST analysis as indicative of lead exposure and toxicity and support its use for further elaboration of lead's effects on renal protein expression.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 0173-0835
    Keywords: Cortex ; Cytoplasm ; Two-dimensional polyacrylamide gel electrophoresis ; Kidney ; Medulla ; Proteomics ; Rat ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: The rodent kidney is a target of many xenobiotics and is typified by regionally specific structure and function. This renders distinct regions of the kidney differentially susceptible to toxic exposure and effect. To characterize these differences at the proteome level, protein patterns from male rat kidney cortex and medulla cytosols were examined by two-dimensional electrophoresis (2-DE) and image analysis and prominent proteins identified immunologically or by matrix-assisted laser desorption/ionization - mass spectrometry (MALDI-MS) and electrospray/ionization - tandem mass spectrometry (ESI-MS/MS) sequence tag identification. An average of 727 protein spots were resolved and matched to the cortex cytosol reference pattern, and 716 in the medulla. Of this total, 127 proteins were found to differ in abundance (86 higher in cortex; 41 higher in medulla) (P 〈 0.001). Of those proteins that were detectable in both cortex and medulla, the abundance of 97 differed significantly while 30 proteins were found to be unique to one region or the other (26 in cortex, 4 in medulla). Twenty protein spots were identified and their regional differences are discussed. These results both confirm and expand our understanding of the molecular heterogeneity characterizing structurally and functionally distinct regions of the kidney and serve as a useful foundation for future nephrotoxicologic studies.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Electrophoresis 18 (1997), S. 642-646 
    ISSN: 0173-0835
    Keywords: Two-dimensional electrophoresis ; Tissue slice ; Testis ; Protein mapping ; Toxicity test ; Dinitrobenzene ; Trinitrobenzene ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Advances in tissue slice technology and a recent novel application of this technique to reproductive toxicology using bovine testis have demonstrated the remarkable utility of this approach. The objective of the present study was to combine this in vitro toxicity test system with large-scale two-dimensional polyacrylamide gel electrophoresis (2-DE) to detect and study alterations in testicular-slice protein patterns as molecular correlates of 1,3,5-trinitrobenzene (TNB) and 1,3-dinitrobenzene (DNB) toxicity. Previous studies have shown that testicular slices remain viable for 〉 24 h and, as measured by protein synthesis inhibition, TNB causes dose-related injury. Tissue-slices were prepared from bovine testicles incubated for 2, 4 or 6 h and exposed to either 100 μM, 500 μM or 1 mM DNB or TNB in the incubation medium. Slices were collected, solubilized, and separated by large scale 2-DE. Resulting protein patterns were then examined by image analysis, which revealed coefficients of variation in protein spot abundance comparable to patterns from fresh rodent tissue samples. Furthermore, specific protein alterations indicated dose-related inductions and declines in protein abundance, some progressive over time. The results of this investigation demonstrate the potential toxicologic utility of combining in vitro tissue-slice technology with high-resolution 2-DE protein mapping. The consolidation of these methods offers a novel approach for toxicity screening and testing, reduces experimental cost, and reduces the use of laboratory animals.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 420-426 
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; Enzyme-catalyzed microreactors ; Quantitation ; In-capillary microreactions ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: This work evaluates the concept of a double enzyme-catalyzed microreactor using capillary electrophoresis (CE). Migrating in a capillary under electrophoresis conditions, plugs of substrate and two enzymes are injected separately in buffer and allowed to react. Extent of reaction and product ratios were subsequently determined by CE. This concept is demonstrated using two model systems: the conversion of adenosine triphosphate (ATP) to adenosine diphosphate (ADP) and adenosine monophosphate (AMP) by hexokinase (HK, EC 2.7.1.1) and apyrase (APY, EC 3.6.1.5), respectively, in the conversion of glucose to glucose-6-phosphate and inorganic phosphate, respectively, and the conversion of nicotinamide adenine dinucleotide, reduced form (NADH), to nicotinamide adenine dinucleotide (NAD) and back to NADH by lactate dehydrogenase (LDH, EC 1.1.1.27) and glucose-6-phosphate dehydrogenase (G6PDH, EC 1.1.1.49), respectively, in the conversion of pyruvate to lactate and glucose-6-phosphate (glc-6-P) to 6-phosphogluconate, respectively. These procedures illustrate the use of the capillary as a double microreactor and the ease of quantitation of reaction products under conditions of electrophoresis.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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