Housing environment influences on chronic stress -induced changes in behavior and neurochemistry: Sex differences in Sprague-Dawley rats.
Item
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Title
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Housing environment influences on chronic stress -induced changes in behavior and neurochemistry: Sex differences in Sprague-Dawley rats.
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Identifier
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AAI9946139
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identifier
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9946139
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Creator
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Beck, Kevin Douglas.
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Contributor
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Adviser: Victoria N. Luine
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Date
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1999
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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
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Abstract
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Wade and Maier's classic study (1986) showed that modeling behavioral impairments due to stress could be greatly influenced by subjects' housing conditions. The work described here sough to determine the extent to which similar manipulations of housing conditions could moderate assessed behavioral and neurochemical measures following chronic stress. Using a 21-day (6-hour) restraint paradigm, housing conditions (food restriction and living alone or with a cage-mate) were manipulated in Sprague-Dawley rats. Both sexes were tested under these conditions to ascertain whether a different pattern of effect on behavior or neurochemistry would immerge after being stress and/or housed in a particular manner. Male rats were most affected by chronic restraint in the object recognition test exhibiting a failure to explore a novel object more so than a previous sample object at delays 2.5-hours or greater. This effect in males was buffered if they were food deprived subsequent to the stress (during behavior testing). Pair housing males was also detrimental to object recognition performance, regardless of stress condition. Double housing during the 3-week restraint period appeared to be a necessary condition for stress-induced object recognition impairments in males. Single-housed stress males were selectively impaired on object placement recognition following a 2.5-hour delay. Stress males, regardless of housing condition, also entered and explored objects in a free open-field quicker than naive males. Females did not show any housing or stress-induced changes in object recognition performance. Stress enhanced object placement recognition above that of naive females who did not show a preference for exploring a newly located object. Double-housed strew females also took significantly longer time to enter a free open-field. Norepinephrine, dopamine, and histidine levels showed the most consistent changes due to stress in prefrontal cortex and hippocampus, but these changes were sex-dependent. Serotonin, glycine, and GABA also showed sex-dependent changes based on housing conditions. These results show that the housing environment of subjects influences both the behavior and underlying neurochemistry of naive and chronically stressed rats, but the pattern differs across sex. Thus, the basic housing environment must be considered a critical variable when modeling behavioral or neurochemical changes across sex.
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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.
