AGE-RELATED CHANGES IN STRESS AND OPIATE RESPONSES IN RATS.
Item
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Title
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AGE-RELATED CHANGES IN STRESS AND OPIATE RESPONSES IN RATS.
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Identifier
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AAI8601666
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identifier
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8601666
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Creator
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KRAMER, ELISSE.
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Contributor
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Richard J. Bodnar
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Date
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1985
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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, Physiological | Gerontology
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Abstract
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Aging is accompanied by impaired regulation of central nervous system responses that play a role in homeostatic functioning and adaptive coping responses to stress. Consequently, the present study assessed whether analgesic and other adaptive responses following morphine administration and acute exposure to two physiological stressors, 2-deoxy-D-glucose (2DG) and cold water swims (CWS), varied as a function of age. Separate age groups of female rats (4, 9, 14, 19 and 24 months) were tested in the three experimental manipulations. In the first experiment, 2DG analgesia (0, 50, 250, 450, 650 mg/kg) was assessed at 3 post-injection intervals on both the tail-flick and jump tests. Subsequently, 2DG (650, 1200 mg/kg) hyperphagia was assessed. Significant decreases in 2DG analgesia were found on both pain tests with increases in age. 2DG hyperphagia was present in the 4 and 9-month groups, absent in the 14-month group, and hypophagic rather than hyperphagic in the 19 and 24-month groups. In the second experiment, CWS analgesia and hypothermia were assessed at 3 intervals following a range of water temperatures (no swim, 21, 15, 8, 2(DEGREES)C). An abrupt decrease in CWS analgesia occurred in the 24-month group on the tail flick test, but a more gradual decline was shown by the 14, 19 and 24-month groups on the jump test. Although all groups displayed a temperature-dependent hypothermia, the three older age groups showed a greater hypothermic response. In the third experiment, morphine analgesia and hyperthermia (0.0, 1.0, 2.5, 5.0, 10.0 mg/kg) were assessed at 4 post-injection intervals. Morphine analgesia on the tail-flick test was delayed but persisted for a longer period of time in the 14, 19 and 24-month groups, whereas consistent reductions were observed on the jump test. In contrast, no age-related differences were found in morphine-induced hypothermia. Thus, with increase in age the analgesic and stress response systems evoked by glucoprivation, CWS, and morphine are differentially affected. Although reduced analgesia was generally observed after all manipulations, the differential patterns of decline following the various manipulations as well as their dissociation from other physiological measures, suggest that aging in rodents is associated with specific rather than generalized changes in adaptive responses to stress.
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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.
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Program
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Psychology
