VOLUNTARY EXERCISE, CHRONIC STRESS, AND BLOOD PRESSURE AND HEART RATE RESPONSES IN THE BORDERLINE HYPERTENSIVE RAT.
Item
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Title
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VOLUNTARY EXERCISE, CHRONIC STRESS, AND BLOOD PRESSURE AND HEART RATE RESPONSES IN THE BORDERLINE HYPERTENSIVE RAT.
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Identifier
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AAI8611386
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identifier
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8611386
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Creator
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SQUIRE, JONATHAN M.
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Contributor
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Robert Fried
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Date
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1986
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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
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Abstract
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The present investigation was concerned with the effect of voluntary exercise in attenuating increases in blood pressure (BP) and heart rate (HR) caused by various stressors in an animal model of borderline hypertension, the borderline hypertensive rat (BHR). Chronic stress has been shown to increase both BP and HR in humans and animals. Forced exercise is known to lower HR, but has equivocal effects on BP. In the first experiment, adult BHR's were subjected to one week of signalled shock followed by six weeks of signalled, unsignalled, or no shock (handled controls). Half of these animals also had free access to a running wheel. BP and HR were measured before and after these treatments. Exercise was found to attenuate the rise in BP and HR due to stress. The exercise effect was most pronounced in the no shock group. These results suggested that voluntary exercise can attenuate increases in HR due to stress, and may be most effective in combination with certain types of stressors. In a pilot experiment, BP was measured via an indwelling catheter. BP increased upon transfer to the shock chamber and upon shock delivery. BP decreased to baseline levels immediately after removal from the shock chamber. In the second experiment, BHR's were subjected daily to anticipation of shock or handling for six weeks. Half of these animals could exercise voluntarily. Control groups for the effects of social isolation were also included. BP and HR were measured weekly under ether anesthesia. BP and HR increased due to both stresses. BP and HR also tended to increase in the socially isolated control groups, possibly due to repeated ether stress. The effect of freely available exercise was found to attenuate stress-induced increases in HR, but not BP. Voluntary exercise may have altered autonomic nervous system responsiveness, local hemodynamic processes in skeletal muscle, and/or resting hormone levels. In the third study, social isolation for one week increased HR. These studies demonstrated that in this animal model, voluntary exercise can reliably attenuate increases in HR but not BP due to chronic stressors and can be an effective protocol for exercise training in rats, and that relatively mild stressors can demonstrably affect BP and HR.
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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
