Biomedical subjects
Publications and source records attributed to R G Burright.
Adult mice were administered the common parasite Toxocara canis or lead or both. The parasite clearly altered mouse performance on tests of exploration, activity, learning, and motor coordination; behavioral effects in mice receiving lead alone were less general. Consequence of Toxocara administration appeared attenuated in animals receiving both agents. Parasite larvae were found in the central nervous system in all infected mice.
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Mice were exposed to lead acetate (0.5%) pre- and postnatally, and activity levels were assessed at 21 days of age. Two measures of open field activity were employed at two different times of day across three doses of d-amphetamine. These factors influence the results observed in lead exposed mice and demonstrate that lead's effects on activity are not invariant. Implications for future research as well as the suggestion of an animal model for childhood hyperactivity are discussed.
The effects of cocaine administration on seizure duration and proportion of animals that seized were examined in mice genetically selected for differential brain weight. In the two experiments reported, mice of the Fuller brain weight lines and of the Binghamton Heterogeneous stock were used. In Experiment 1, 21 day old male and female mice were administered either 0, 5, 10 or 20 mg/kg of cocaine hydrochloride. Fifteen minutes after each mouse was injected, a transcorneal shock was administered to that animal. Type and duration of seizure were measured. Low brain weight mice were more susceptible to seizures and showed more severe seizures than the medium and high brain weight mice or the Heterogeneous stock. Cocaine hydrochloride provided a degree of protection against seizures in a dose dependent fashion, particularly in the medium brain weight and Heterogeneous stock mice. Experiment 2 examined whether repeated daily doses of cocaine (15-21 days of age) would alter the pattern of susceptibility described above. In this experiment mice were given either 0 mg/kg or 10 mg/kg of cocaine hydrochloride. At 21 days of age, 15 minutes after injection, mice were subjected to transcorneal shock and the subsequent nature and duration of seizures observed. Mice of the low brain weight line were again seen to have more seizures than those from the high brain weight line. Cocaine decreased the severity of transcorneal induced seizures.
Ingestion of palatable and unpalatable solutions was measured in adult mice in which had been administered the common parasite of the dog, Toxocara canis alone, or in combination with lead. In addition, response to hot plate and susceptibility to electroconvulsive seizure were also measured. Results from the palatability test indicated that either lead or Toxocara may alter the mouse's mode of interacting with its environment. However, the two agents in combination interacted in their effects on consummatory behavior. Results from the hot plate and ECS measures were less clear with respect to how lead and/or Toxocara influence temperature reactivity and seizure susceptibility. Histological examination of the CNS in parasite infected animals revealed Wallerian Type degeneration of fiber pathways including the corpus callosum, olfactory tract, and cerebellar penduncles.
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We present a simple two-chamber apparatus for avoidance training of mice which does not require a shock scrambler. This apparatus can be used for active, passive and discriminated (Go-No-GO) avoidance tasks.
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Rats which had received septal lesions or underwent control surgery were exposed to stress in four experiments. We examined plasma corticosterone (Experiment 1), gastric ulceration (Experiment 2), motor activity (Experiment 3) and whole brain norepinephrine (Experiment 4) following 3 hours of prone-restraint-stress conditions at 21 degrees C or 5 degrees C. Rats with special lesions had higher steroids, less severe ulceration, greater motor activity and higher brain norepinephrine than controls following stress. Changes in hyperemotionality and differences in coping strategies are discussed.
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The differential effects of continued maintenance on a 12% vs. 24% protein diet were examined in immature and middle-aged male and female C57BL/6J mice. Exploratory behavior, body weight and fluid consumption of water, saccharin and quinine were monitored over 9 weeks of presentation of the special diets. No rehabilitation datawere obtained. The dietary manipulations differentially effected the various groups, but the pattern of change in behavior was a function of the age and sex of the subject and the specific measure employed.
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Rats reared under dietary enrichment or standard diet from 25 days of age underwent septal or control surgery 2 months later. Enrichment differentially altered septal or control behavior as measured by: exploration tests: fluid consumption of water, saccharin, and quinine; and the acquisition of an active avoidance task.
Septal lesions or control operations were produced in male and female rats. Measurements of water and food consumption were carried out while the rats were housed under warm vivarium temperatures (24 degrees C) and when maintained in a cold room (6 degrees C). Examination of the data from the entire week spent in the cold revealed that rats with septal lesions deviated from precold water-comsumption levels less than comparable control rats. Further, whereas rats with septal lesions suppressed intake for the first 24 hr following either shift in environmental temperatures, control animals inhibited drinking only when returned to the warm environment. Both surgical groups elevated food consumption in the cold. The relative amount of food and water consumed during the day (vs night) increased for all groups when maintained in the cold. Differences in degree of reactivity to the manipulations were observed in male and female rats. These findings were interpreted as adding further support to our contention that septal lesions alter the behavioral (rather than direct metabolic) adaptations an animal makes to its environment.
Consumption of water and adulterated fluids was measured under choice and no choice situation in voles and gerbils. Voles consumed more water throughout, and were clearly less able to tolerate challenges presented by adulteration of available solutions in the no choice situation. Intake of both species under choice conditions was more affected (although differentially) by fluid adulteration that it had been when no choice was available. Male and female differences were noted but typically these differences were in magnitude rather than direction of the consummatory response. The data were taken to illustrate the need for comparative studies and careful specification of stimulus conditions surrounding testing so that general principles of physiological and behavioral regulation can be separated from species specific differences.
In order to separate species specific from general effects of septal lesions on consummatory and investigatory behavior we chose to work with male Mongolian gerbils and meadow voles. These two rodent species are different in both the absolute amount of fluids consumed and reactivity to the palatability of the fluids presented in a single tube. Septal lesions did not elevate water consumption of either species. Septal lesioned gerbils tended to consume more sucrose, and septal voles clearly did drink more sucrose than their control counterparts. But only lesioned voles suppressed intake below control levels when presented with quinine. Exploratory behavior, which was measured only in gerbils, was also altered by septal lesions. Measurement of testosterone, seminal vesicles, and ventral marking glands (gerbils only) indicated that septal lesions alter hormonal systems in at least this species. The importance of comparative investigations in elucidating the general function of brain structures was discussed.