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Biomedical subjects

I Geller

Publications and source records attributed to I Geller.

At least 19 recordsLinked to original sources
PubMed1985

Neurobehavioral effects of repeated sublethal soman in primates.

Juvenile male baboons were trained to perform a match-to-sample discrimination task; effects of repeated sublethal exposure to the organophosphate nerve gas, soman, upon task performance were then explored. Both acute and subchronic exposure schedules were employed, and soman potency was verified by assay of soman-induced inhibition of acetylcholinesterase activity in whole blood, plasma, and erythrocytes. A characteristic profile of behavioral effects encompassing immediate, persistent, and delayed effects was observed. Immediate dose-related effects of soman included: increases in mean session response time, increases in errors, and decreases in extra responses. Seizures were also observed at the highest dose of soman employed (5 micrograms/kg). The increase in mean session response time was due to intermittent lapses in responding to stimuli (attentional deficits). Both the attentional deficits and intermittent generalized seizures were also persistent effects, with both occurring randomly after acute exposure to 5 micrograms/kg soman. Preliminary evidence suggests that occurrence of attentional deficits was associated with the occurrence of generalized and/or focal seizures; and that these effects may reflect irreversible lesions which become more threatening to the animal with increasing time. An additional, delayed effect was a sudden marked increase in the incidence of extra inconsequential responses which occurred several weeks after cessation of soman exposures.

Acetylcholinesterase↗
PubMed1985

Toluene and ethanol effects on baboon match-to-sample performance: possible synergistic action.

Four juvenile male baboons were trained to respond for banana pellet rewards on a match-to-sample discrimination task. Exposure of the animals to a range of concentrations of either toluene or ethanol vapor resulted in a slowing of response times and a reduction in the percent trials attempted for some concentrations of either vapor. When behaviorally ineffective (subthreshold) concentrations of each vapor were combined, effects upon response times and trials attempted were similar to the effects produced by the higher concentrations of the individual vapors. However, while high concentrations of ethanol vapor produced errors in half of the subjects, combinations of ethanol and toluene did not increase this effect. This information suggests an ethanol potentiation of toluene effects, rather than the reverse.

Animals↗
PubMed1985

Acute soman effects in the juvenile baboon: effects on a match-to-sample discrimination task and on total blood acetylcholinesterase.

Male juvenile baboons, trained on a match-to-sample operant discrimination task, were given acute intramuscular injections of soman (methyl pinacolyl phosphonofluoridate) at 1.0, 2.0, 3.0, 4.0, and 5.0 micrograms/kg. The different doses were given in a mixed order just before a behavioral test session. Just prior to administration of each soman dose and immediately following the 2-hr behavioral test session, a sample of blood (0.5 ml) was drawn from the baboon and analyzed for inhibition of acetylcholinesterase activity. Thereafter, blood sampling was accomplished at weekly intervals and soman was administered again only when whole blood acetylcholinesterase reached at least 80% of pre-soman control level. Behavioral effects of soman included a slowing of response times, a decrease in extra inconsequential responses, a decrease in responsiveness to the visual stimuli and an increase in errors. These effects were observed when acetylcholinesterase (AChE) levels fell to 25 mumoles/hr/ml blood or less. The threshold dose for behavioral effects was very close to the dose of soman which induced seizures.

Acetylcholinesterase↗
PubMed1985

Effects of subchronic administration of soman on acquisition of avoidance-escape behavior by laboratory rats.

Holtzman male Sprague-Dawley rats were given four injections of saline or soman at 31 micrograms/kg or 46 micrograms/kg. The injections were given every 3 days during a 2-week period. Tail vein blood samples, drawn 24 hr before the first injection and 24 hr after the last injection, were analyzed for acetylcholinesterase (AChE) inhibition. For the low and high soman groups, whole blood AChE was inhibited 20 and 24%, respectively, while plasma AChE was inhibited 17 and 25%, respectively. Parallel saline injections produced a small inhibition of whole blood AChE and an increase in activity (negative inhibition) of plasma AChE. During the second week of soman administration rats began training on a discriminated shock avoidance task. The seven animals administered 46 micrograms/kg soman did not learn the lever-pressing avoidance response during a period of 120 days. Five of eight saline rats and four of seven 31 micrograms/kg soman rats learned the avoidance response. There was no significant difference between learners relative to rate of learning of the avoidance task. All of the rats learned to escape the shocks. These data indicate that subchronic soman inhibits learning of new behaviors by laboratory rats.

Acetylcholinesterase↗
PubMed1983

Toluene inhalation and anxiolytic activity: possible synergism with diazepam.

Toluene exposures or injections of diazepam reinstated lever responses that had been suppressed by punishment in laboratory rats. When concentrations of toluene or diazepam that were ineffective or minimally effective in this paradigm were administered in combination, they produced a qualitatively similar effect which was much greater than the sum total of effects produced by the same amount of either substance alone. These observations suggest an anxiolytic action for toluene and a possible synergism between the two substances.

Animals↗
PubMed1983

Phenobarbital and d-amphetamine effects on discrimination performance of rats and juvenile baboons.

Hungry rats in Skinner boxes were trained to select the right or left lever as correct as a function of the presence of a tone or light stimulus, respectively. Correct responses produced liquid food rewards. Acute intraperitoneal administration of d-amphetamine or phenobarbital did not affect accuracy of performance, but decreased the percent trials attempted and lengthened response times as a function of increasing doses. The mean extra responses during the delay intervals generally decreased under phenobarbital and increased under d-amphetamine. Juvenile baboons were trained to respond on a delayed match-to-sample task in order to obtain banana pellet rewards. Acute intramuscular administration of phenobarbital produced a dose-related increase in errors, a decrease in mean extra responses and an increase in response times. A slight reduction in the percent trials attempted occurred only at the highest dose of the drug. Acute intramuscular d-amphetamine did not increase errors even at dose levels that increased reaction times, decreased extra responses and reduced the percent trials attempted.

Animals↗
PubMed1983

Effect of exposure to high concentrations of toluene on ethanol preference of laboratory rats.

Male and female Holtzman Sprague Dawley rats were given 10-minute exposures to high concentrations of toluene twice a week at 10-30 days of age. The rate of acquisition of ethanol preference for these rats did not differ significantly from litter-mate sham exposed controls. Once ethanol preference curves were established, the rats were exposed daily over a 5-day period to high concentrations of toluene. An increase in ethanol intake occurred in most of the rats irrespective of early toluene exposures at 10-30 days of age.

Alcoholism↗
PubMed1982

Effects of buspirone on operant behavior of laboratory rats and cynomolgus monkeys.

Rats trained on an avoidance-escape task were administered buspirone in doses ranging from 0.5 to 7.5 mg/kg. Low doses disrupted avoidance responding without impairing escape responding. Rats trained on an experimentally induced conflict procedure were also administered buspirone or diazepam (1.0 to 5.0 mg/kg). Buspirone and diazepam appeared to be equipotent as anxiolytics. Cynomolgus monkeys, also trained on the experimentally induced conflict task, were given intramuscular buspirone or diazepam (0.5 to 5.0 mg/kg). Both drugs produced an attentuation of conflict, further supporting the anxiolytic equipotency of buspirone and diazepam. The long duration of action of buspirone suggests the presence of at least one active metabolite.

Animals↗
PubMed1979

Effects of acetone and toluene vapors on multiple schedule performance of rats.

Six rats were trained to press a lever for a liquid food reward on a multiple fixed ratio--fixed interval (FR--FI) schedule of reinforcement. When lever-pressing rates became relatively stable, the animals were exposed to 150 ppm of either acetone or toluene for duration times of 1/2, 1, 2 and 4 hr. Exposures were conducted at least three weeks apart. Acetone produced minimal changes on the FR--FI responding during the 1/2 hr exposure. During the 1 hr exposure period, both FR and FI rates increased while during the 2 hr exposure, both FR and FI responses decreased below control levels. During the 4 hr exposure FI responses approximated control levels for 2 rats and were above the control level for the third animal while FR rates were below controls for 2 of the 3 subjects. Rate changes under toluene were generally qualitatively similar to those produced by acetone. An initial enhancement of FR and FI rates occurred during the shorter exposure periods followed by a decrease in rates during the longer exposure periods.

Acetone↗
PubMed1979

Effects of acetone, methyl ethyl ketone and methyl isobutyl ketone on a match-to-sample task in the baboon.

Acetone, methyl ethyl ketone (MEK) and methyl isobutyl ketone (MIBK) were evaluated for effects on a delayed match-to-sample discrimination task in the juvenile baboon. The animals were exposed to 1/2 the threshold limit value (TLV) of each gas for 24 hr per day during a 7-day period. They were also exposed to a combination of MEK and MIBK at the same exposure concentrations. Each exposure condition affected accuracy of performance minimally but resulted in increased and decreased extra responses during the delay intervals. Response times were slowed under acetone, MEK or MIBK. In contrast to the effects of the individual gases, exposure to a combination of the same doses of MEK and MIBK produced a consistent increase in extra responses during delay and a concomitant decrease in response times. Changes in tissue uptake and metabolism are suggested as possible mechanisms to explain this observation.

Acetone↗