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  • 1
    ISSN: 1572-9834
    Keywords: Wetlands ; conceptual model ; indicators ; prairie pothole region ; EMAP
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The U.S. Environmental Protection Agency's (EPA's), Environmental Monitoring and Assessment Program (EMAP) is developing a landscape-level conceptual model to evaluate the condition of depressional (basin-type) wetlands in the prairie pothole region (PPR) of the United States. This effort is underway to determine the current condition of the Nation's wetlands and to track how it is improving or degrading over time, as well as to identify management priorities over major geographic areas. The depressional wetlands in the PPR were selected by EMAP both because of the importance of this region for waterfowl and because of the efforts currently being conducted by federal agencies and academic institutions in this region. The PPR provides nesting habitat for more than 15 species of ducks, and supports as much as half of the total production of dabbling and diving ducks in North America. Wetlands in this area became a vulnerable resource after extensive draineage in the 1800s. We propose a conceptual model that represents a framework for guiding the development of ecological indicators, research activities, and data collection for the evaluation of wetland conditions. In princple, this conceptual model is applicable to wetlands in any part of the world.
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Mycopathologia 22 (1964), S. 65-72 
    ISSN: 1573-0832
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A case of generalised infection withH. capsulatum is described in which the main stress was on the lungs and in the latter stage an ulcer in the oral cavity developed. The fungus was recovered from the sputum as well as the ulcer.
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  • 3
    ISSN: 1432-2072
    Keywords: Drug discrimination ; Pentylenetetrazol ; Cocaine ; Learning
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Rats were trained to discriminate “drug” from “no drug” in a two-lever, food-reinforced task. One group was trained with cocaine (10 mg/kg) and a second group was trained with pentylenetetrazol (20 mg/kg). A method designed to shorten the time required for the training phase of drug discrimination experiments was assessed in subgroups for each drug. In one subgroup, single training sessions were conducted daily. In the other subgroup, a second session (either drug or saline) was conducted on days for which the first condition was saline. The training conditions were presented in an irregular sequence, with the same condition occurring in no more than two consecutive sessions. Rats trained by the accelerated method learned the discrimination in fewer days, with no decrement in acquisition per session, suggesting that drug discrimination training can be accomplished more rapidly by reducing inter-session interval.
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  • 4
    ISSN: 1432-2072
    Keywords: Key words  m-Chlorophenylpiperazine ; Drug discrimination ; Ethanol withdrawal ; Anxiety ; 17β-estradiol ; Sex difference ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Rationale: The serotonergic system plays a role in regulation of anxiety and ethanol withdrawal (EW). Nevertheless, few studies have assessed sex differences in serotonergic effects on EW. Objectives: This study examined sex differences in the anxiogenic stimu-li induced by a serotonin (5-HT)1b/2 agonist, meta- chlorophenylpiperazine (mCPP), prior to ethanol and during EW. Methods: Gonadectomized or sham-operated adult male and female rats and 17β-estradiol (2.5 mg, 21-day release, s.c.) -replaced ovariectomized (OVX) rats were trained to discriminate mCPP (1.2 mg/kg, i.p.) from saline in a two-lever choice task for food. Latency to the first lever press and mCPP lever selection were measured following mCPP (0–1.2 mg/kg). Rats then received chronic ethanol-containing liquid diet (6.5%) for 10 days and were tested for mCPP lever selection 12 h and 36 h after removal of ethanol. Results: Fewer sham female and β-estradiol-replaced OVX rats selected the mCPP lever than male or OVX rats, and showed an increased initiation latency after mCPP injection. During EW (12 h and 36 h), fewer sham female and β-estradiol-replaced OVX rats responded on the mCPP-lever after saline injection as well as after mCPP challenge than male or OVX rats. Castration did not alter any response of male rats to mCPP. Conclusions: (1) mCPP discrimination is a useful measure of EW in male and female rats; and (2) sham female and β-estradiol-replaced OVX rats are less sensitive to the discriminative stimulus prior to and during EW, but more sensitive to impaired behavioral initiation induced by mCPP than male or OVX rats.
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  • 5
    ISSN: 1432-2072
    Keywords: Pentylenetetrazol ; Drug dependence ; Withdrawal ; Mecamylamine ; Discrimination ; Diazepam ; Nicotine ; Anxiety
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Rats were trained on an FR10 schedule of food reinforcement to press one lever after pentylenetetrazol (PTZ), 20 mg/kg, IP, and an alternate lever after saline. After acute nicotine, 0.64 mg/kg, SC, 35% of the rats pressed the PTZ-lever. Diazepam, 5 mg/kg, IP, blocked the stimulus produced by PTZ, and mecamylamine, 5 mg/kg, IP, blocked the stimulus produced by nicotine. Training was then suspended and rats were treated with nicotine, at 8-h intervals, 0.64 mg/kg on the 1st day, and 1.25 mg/kg on subsequent days, for 21 days. To determine whether nicotine withdrawal substitutes for the stimulus produced by PTZ, rats were tested with saline at various times after chronic nicotine injections. Data from this part of the study were replicated in another group given nicotine for 15 days. Saline at 8 h after nicotine (five determinations each group) produced a small but stable degree of PTZ lever selection (35±4%). At 48 h after termination of nicotine treatment, the percentage of rats selecting the PTZ lever (50%) was greater than that in a control group tested after an equivalent period without training. The PTZ-like stimulus detected after chronic nicotine was not altered by mecamylamine, was additive with PTZ, and was blocked by diazepam. These data suggest that withdrawal from chronic nicotine produces a weak PTZ-like stimulus, which can be antagonized by an anxiolytic drug.
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  • 6
    ISSN: 1432-2072
    Keywords: Drug discrimination ; Pentylenetetrazol ; Operant behavior
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Rats were trained to discriminate pentylenetetrazol (PTZ, 20 mg/kg) from saline in a two-lever operant task. Correct lever presses were reinforced with food under the control of a fixed ratio 10 schedule. In tests of the effect of PTZ dose on level selection, rats selected the PTZ lever in a dose-dependent manner, with peak latency at the approximate ED50 dose (10 mg/kg). Rats usually pressed only the selected lever, regardless of dose, indicating that lever selection was a quantal (or bimodal) function of stimulus intensity. Lever biases observed during training sessions did not predict the performance of individual rats in tests with the ED50 dose. In three independent trials with this intermediate dosage, the rats selecting the PTZ lever varied from trial to trial, suggesting that rats detecting this dose did not form a stable subgroup. The pattern of lever selections across these three trials was not significantly different from that predicted by a model in which all subjects shared the same probability for detecting the drug stimulus. These results demonstrate that lever selection in a two-lever drugdiscrimination task can be quantal in nature, and suggest that rats trained with PTZ, 20 mg/kg, are homogeneous in sensitivity to this stimulus.
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  • 7
    ISSN: 1432-2072
    Keywords: Drugs of abuse ; Drug withdrawal ; Drug discrimination ; Discriminative stimulus ; Withdrawal signs ; Withdrawal symptoms ; Benzodiazepines ; Diazepam ; Ethanol ; Cocaine ; Anxiety ; Drug dependence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract There have been few attempts to model subjective symptoms of drug withdrawal using animals as subjects. Two approaches for developing such models are reviewed. First, using drug discrimination methodology, it may be possible to train animals to detect the effects of withdrawal. This method has two difficulties: 1) the only discriminations trained to date involve precipitated withdrawal, and 2) the stimulus controlling behavior is difficult to specify. Second, withdrawal from many drugs of abuse produces the symptom of anxiety, and it seems likely that animal models of anxiety could be useful for studying drug withdrawal. This hypothesis has been explored most fully using subjects trained to detect the discriminative stimulus properties of the putative anxiogenic drug pentylenetetrazole (PTZ). Withdrawal from benzodiazepines or ethanol substitutes fully for PTZ, and withdrawal from cocaine, morphine, and nicotine substitutes partially for PTZ. Emerging data suggest that other animal models of anxiety may also be useful for detecting drug withdrawal. The final portion of this review examines a behavioral test that is very sensitive for detecting physical signs of withdrawal in animals. In subjects maintained on an operant baseline using food as a reinforcer, withdrawal from a drug of dependence frequently is associated with disruption of that operant behavior. For example, tetrahydrocannabinol and cocaine, drugs that are not traditionally seen as having significant withdrawal signs, produce disruption of operant responding when high-dose administration is terminated, and their readministration reverses this behavioral disruption. Based on the observation that withdrawal is associated with anxiogenic stimuli, we suggest a method to determine if disruption of operant behavior may be related to these stimuli.
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  • 8
    ISSN: 0368-1874
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 0368-1874
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology
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  • 10
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Journal of Electroanalytical Chemistry 96 (1979), S. 175-181 
    ISSN: 0368-1874
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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