PubMed Health⌕ Search

Biomedical subjects

T E Levine

Publications and source records attributed to T E Levine.

6 recordsLinked to original sources
PubMed1978

Effects of caffeine on DRL performance in the mouse.

Mice were trained to stable and efficient DRL 18 sec performance utilizing a nose-poke as the operant. Caffeine, at doses less than 48 mg/kg, increased both response bursts (IRTs less than 3 sec) and longer IRTs, and shifted the IRT distribution towards shorter, nonreinforced IRTs. Auditory feedback for responses decreased the number of bursts emitted and produced performance more resistant to drug effects. These results are similar to those previously reported for caffeine on DRL in the rat, and for amphetamine on DRL in a variety of species.

Acoustic Stimulation↗
PubMed1977

Technique for assessing visual discrimination learning in mice.

An automated technique for the study of visual discrimination learning in mice has been developed. The technique utilizes a nose-poke as the operant response. The nose-poke response requires no shaping, has a relatively high operant level and can be used to measure preacquisition exploratory behavior. CD-1 mice acquired a simultaneous brightness discrimination readily but a successive brightness discrimination proved more difficult. A 20 sec intertrial interval was optimal for acquisition of the simultaneous discrimination. Reversal learning was slow. This procedure should prove useful in the study of the effects of pharmacologic and toxic agents on learning and performance in both weanlings and adult mice.

Animals↗
PubMed1976

Studies in the behavioral toxicology of environmental contaminants.

Behavioral toxicology represents a relatively new research area in the West, and a new source of information pertinent to standard setting. Despite this abbreviated history, however, it can call on a rather advanced technology, largely provided by the rapid and extensive development of behavioral pharmacology during the past two decades. As exemplified by the U.S. contribution to the joint study of carbon disulfide, the approach derived from this background relies on the acquisition of dose--effect data with a preparation yielding stable baseline performance. The first study in this collaborative series employed pigeons trained to peck a response device consisting of a transilluminnated plastic disk. Various relationships between this response and the occasions on which it led to the delivery of food were explored in order to ascertain which behavioral variables were most sensitive to acute exposures. In addition, a central nervous system drug, whose neurochemical mode of action is believed to parallel that of carbon disulfide, was tested in the same preparations. Further research on these questions is being continued with monkeys.

Animals↗
PubMed1976

Effects of carbon disulfide and FLA-63 on operant behavior in pigeons.

Carbon disulfide (CS2) and FLA-63 [bis(4-methyl-1-homopiperazinylthiocarbonyl)disulfide] were studied in pigeons working on a differential-reinforcement-of low-rates or a multiple fixed-interval fixed-ratio schedule of food reinforcement. Response rate on both schedules decreased after 8-hour exposures to CS2 (2 mg/1) of administration of FLA-63 (40 and 80 mg/kg). The effects of two successive 8-hour exposures to CS2 were cumulative and ten successive 4-hour exposures produced changes in differential-reinforcement-of-low-rates performance resembling those following acute exposure. Fixed-interval performance was disrupted by exposures to CS2 and doses of FLA-63 that left fixed-ratio performance intact.

Animals↗
PubMedDate not supplied

Workshop on the qualitative and quantitative comparability of human and animal developmental neurotoxicity, Work Group IV report: triggers for developmental neurotoxicity testing.

A Work Group was formed to evaluate the criteria considered important in determining when to require developmental neurotoxicity testing in animal studies (i.e., triggers for testing). The primary objective of the Work Group was to determine whether there is sufficient scientific evidence to support the triggers identified by the Environmental Protection Agency and determine whether there is sufficient evidence to use structure activity relationships (SAR) to trigger automatic testing of certain classes of chemicals. A weight of evidence (WOE) approach was recommended by the Work Group in order to assist in determining which agents should undergo developmental neurotoxicity testing and to what level of testing. Evaluation of biological effects, length and duration of exposure, and quality and quantity of data available on an agent should be used in the WOE approach. Agents that are teratogenic to the central nervous system (CNS) were considered of highest priority for developmental neurotoxicity testing, especially if there is the potential for a high degree of exposure. Neuropathic and neuroactive compounds, chemicals with hormone-like activity, and developmental toxicants (with effects other than structural abnormalities of the CNS) were also considered likely candidates for such testing. Although reluctant to recommend testing based solely on SAR or chemical class, the Work Group recognized the importance of considering SAR along with other toxicity data, pharmacokinetic data and potential human exposure in making final requirements or recommendations for further testing.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗