The effects of chronic restraint stress on behavioral, neuroendocrine, and neurochemical responses in female rats.
Item
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Title
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The effects of chronic restraint stress on behavioral, neuroendocrine, and neurochemical responses in female rats.
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Identifier
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AAI3047744
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identifier
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3047744
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Creator
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Bowman, Rachel E.
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Contributor
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Adviser: Victoria N. Luine
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Date
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2002
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Language
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English
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Publisher
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City University of New York.
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Subject
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Psychology, Psychobiology | Psychology, Physiological | Psychology, Experimental
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Abstract
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While stress is a common to all animals, the stress response is sex dependent and limited work has shown sex differences in the male and female response to stress. Effects of chronic restraint stress, (6h/day, 21 and 28 days) in intact female rats were examined. Stressed rats had higher corticosterone levels during the stress period but levels returned to baseline at 15 days post-stress. Stress had no effect on estrous cycle lengths, but led to less weight gain. Following the stress period, subjects were tested for open field (OF) activity and radial arm maze (RAM) performance. Females stressed for 21 days showed enhanced spatial memory performance on the RAM, but females in proestrus, regardless of stress, had impaired acquisition. A longer period of restraint, 28 days, also led to less weight gain by stressed subjects and unaltered estrous cycle lengths, but was not associated with enhanced RAM performance, except stressed females in proestrus performed better than proestrus controls. Following sacrifice, brain areas contributing to learning and memory were assessed for neurotransmitter levels. Following both 21 and 28 days of stress, dopaminergic activity was increased in prefrontal cortex and regions of the hippocampus.;To assess ovarian hormone contributions to the female stress response, effects of 21-days of stress in ovariectomized (OVX) rats receiving either cholesterol or estradiol replacement were examined. OVX-stress subjects were not impaired and stressed subjects receiving estradiol showed the best RAM performance. Monoamine and amino acid levels changed in response to both stress (e.g., decreases dopamine metabolites in prefrontal cortex) and estradiol (e.g., increased CA3 levels of norepinephrine).;Finally, stress alone, without behavioral testing, did not alter neurotransmitter levels, but corticosterone was correlated with specific neurotransmitters in stressed and control subjects, suggesting that the experience of stress may alter neurochemical responses differentially following specific cognitive demands.;In summary, the current studies provide novel behavioral, neuroendocrine and neurochemical information about the stress response in female rats. Results show that estradiol may moderate stress effects on cognition, as compared to males, through both organizational and activational effects and that interactions at monoaminergic terminals may be important in mediating the effects.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
