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Biomedical subjects

C I Thompson

Publications and source records attributed to C I Thompson.

54 records · Page 3Linked to original sources
PubMed1979

Hypophagia follows the initial hyperphagia produced by 2-deoxy-D-glucose in rats.

The glucose analogue 2-deoxy-D-glucose (2DG) inhibits glucose metabolism and causes a rapid increase in food consumption in most species. This increase is most apparent during the first 6 postinjection hours, although it may persist as long as 10 hr. There are no published descriptions of alterations in food consumption subsequent to the hyperphagia. In the present study male and female rats were injected with 2DG (750 mg/kg IP), insulin (regular, 20 U/kg SC) or distilled water, and food intake was compared to baseline levels during the next 1, 6 and 24 hr. Results showed that food intake: (1) was not affected by injections of water: (2) was higher than normal during all 3 time periods following insulin injections: and (3) was higher than normal at 1 and 6 hr following 2DG, but significantly lower than normal by the end of 24 hr. The reasons underlying the development of hypophagia subsequent to the initial hyperphagia produced by 2DG are presently unknown.

Animals↗
PubMed1979

Learning ability in adult female rats perinatally exposed to methadone.

Cognitive functioning of adult female rats that were maternally exposed to methadone (5 mg/kg daily) during gestation and/or lactation was studied by assessing performance on a food-motivated light-dark discrimination learning test and on active and passive shock-avoidance tests. Methadone-exposed rats exhibited difficulties on the light-dark discrimination learning and the active avoidance tests, and behavioral deficits appeared to be related to the timing and duration of drug treatment. On the light-dark discrimination test only 33% of the rats in the gestation group and 25% of the animals in the lactation group met criterion in comparison to 87% of the control rats. Thirty-three percent of the animals in either the gestation or gestation-lactation groups met criterion on the active avoidance test in contrast to 87% of the controls. These data suggest that perinatal exposure to methadone impairs cognitive abilities in the adult female rat.

Animals↗
PubMed1979

Imparied thermal regulation in juvenile rats following perinatal methadone exposure.

Offspring of female rats injected daily with methadone (5 mg/kg) or saline were cross-fostered at birth to form groups exposed to methadone during gestation (G), lactation (L), or gestation and lactation (G-L); controls (C) were exposed only to saline. Rectal temperature, body weight and food consumption were measured from postnatal Days 36-51. Ambient temperature was maintained at 21 degrees C except for Days 42--45, when the temperature was 10 degrees C. Group G rats never differed from controls, but offspring in Groups L and G-L were hypothermic at room temperature; Group G-L rats exhibited a further temperature loss during the cold stress. There were no group differences in food consumption after Day 39, and all groups increased food intake while in the cold. Group differences in body weight were not reliable but Group G-L rats gained less weight than the rest during the experiment, whereas Group L rats gained more. These results indicate that, depending upon treatment schedule, perinatal methadone exposure is associated with hypothermia during the postweaning period. A prolonged withdrawal reaction from methadone may account for the impaired thermal regulation.

Animals↗
PubMed1979

Development of motor activity in young rats following perinatal methadone exposure.

Ambulatory behaviors of 21, 45, and 60 day old rats exposed to methadone (5 mg/kg) during gestation and/or lactation were studied by assessing locomotion in an activity cage, open field, and activity wheel, and latency times to step down from an elevated platform. Methadone-exposed rats were found to be generally less active than controls at 21 days of age and more active than saline-treated pups at the 45 and 60 day test periods. In addition, behavioral responses appeared to be dependent on the timing and duration of opioid treatment. These data suggest that prenatal and/or postnatal methadone exposure affects behavior in young rats and provide a functional correlate to our earlier observations of microscopic and neurochemical changes in the brains of methadone-treated offspring.

Aging↗
PubMed1977

Social and nonsocial behaviors of adult rhesus monkeys after amygdalectomy in infancy or adulthood.

At 6 yr of age six female rhesus monkeys that had sustained bilateral amygdalectomy in infancy, and five intact controls, were transferred to an observation cage where behaviors were recorded while the monkeys were (a) alone, (b) paired with unfamiliar stimulus animals, and (c) paired with familiar monkeys from the opposite experimental group. The five adult controls then underwent amygdalectomy, and all tests were repeated with the infant- and adult-operated animals. Infant-operated monkeys changed behaviors more rapidly than did intact controls in social and nonsocial situations, and their activity levels were less modified after a 24-hr period in the observation cage. They were subordinate to intact controls but expressed less fear than did controls when briefly placed with an unfamiliar aggressive animal. Adult amygdalectomy produced many changes in behavior, but these aberrations were identical to those observed in like-age monkeys that had been amygdalectomized in infancy. Infant-operated monkeys demonstrated more behavioral deficits at 6 yr than they had earlier in life.

Age Factors↗
PubMed1976

Growth in the Hubbard broiler: increased size following early handling.

Hubbard cockerels, 1 day of age (n = 91), were divided into 3 handling groups: (1) chicks from the 5-Day group were removed from the brooder and isolated at 22 degrees C for 3 min on each of the first 5 days; (2) chicks from the 15-Day group received this treatment for 15 days; and (3) Control chicks were not handled. Within each group half were fed broiler starter for 5 weeks, and half were fed layer starter which produces slower growth. On Days 28, 35, 42, and 49 the average weight of 5-Day birds was significantly higher than that of Controls; 15-Day birds weighed slightly less than birds in the 5-Day group. The weight advantage of the 5-Day birds occurred with both starter rations, at all weighing periods, and did not appear to reflect increased food consumption. Similarities between these findings and results obtained with rodents were noted.

Age Factors↗
PubMed1976

Age differences in aversively motivated visual discrimination learning and retention in male Sprague-Dawley rats.

Rats 3, 7, 12, and 24.5 mo. old were trained to an 11/12 correct initial response criterion on a shock-motivated light-dark discrimination. Eight days later they were retrained to the same criterion. Original learning and relearning rates were not correlated, but both decreased linearly with increasing age. Ray and Barrett (1973) recently reported that, while year-old rats made fewer avoidances than younger animals on a shock-motivated discrimination, they appeared to have learned equally well, since there were no differences in number of correct initial responses. They suggested that avoidance scores may reflect performance factors and that learning decrements with age might not occur if the correct initial response measure were used. The present study demonstrates that this is not the case; when rats as old as 24.5 mo. are tested there are clear age-related deficits in number of correct initial responses.

Aging↗
PubMed1970

Effects of combined frontal and temporal lesions on learned behaviors in rhesus monkeys.

Delayed response ability, and to a lesser extent visual discrimination performance, is seriously impaired by extensive bilateral damage to the frontal lobes. Reciprocal anatomical connections between the frontal and temporal lobes suggested that massive lesions in both lobes might produce an impairment more complete than that resulting from frontal lobectomy alone. Five monkeys were given combined bilateral frontal and anterior-temporal lesions, and were found to be inferior to both frontal lobectomized monkeys and to unoperated controls on the object discrimination task. The combined lesion did not increase the deficit on delayed response over that obtained after only bilateral frontal lobectomy. Results indicate that the anterior-temporal neocortex is involved in the mediation of visual discrimination ability.

Animals↗
PubMedDate not supplied

Reduced social dominance in rats perinatally exposed to methadone.

Offspring of female rats injected daily with dl-methadone hydrochloride (5 mg/kg, IP) or saline were cross-fostered at birth to form drug groups exposed throughout gestation only, or both gestation and lactation; controls were exposed only to saline. At approximately 80 days, 120 offspring (20 from each drug group and 60 controls, sexes equally represented) were adapted to a 23-hr water deprivation schedule and individually trained to obtain water in a test cage containing a single water spout. Each methadone-exposed rat then competed with a control animal for access to the water during two 5-min sessions. Under competitive conditions, methadone-exposed rats spent less time at the water spout than did the controls (p less than 0.02); this effect occurred in males and females from all three drug group, and was unrelated to body weight. These results suggest that social dominance may be reduced in the offspring of mother rats given methadone.

Animals↗