Effects of acute and chronic exercise on vasoconstrictor responsiveness of rat abdominal aorta /
Previous work has demonstrated that vascular response hics.
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
1998.
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| Summary: | Previous work has demonstrated that vascular response hics. to the []-adrenergic agonist phenylephrine (PE) is diminished after a single bout of exercise. The purpose of this study was to determine the mechanism responsible for this decreased sensitivity to PE immediately following exercise and whether it involves the endothelial and the nitric oxide (NO) pathway. A secondary purpose was to determine whether this diminished vascular responsiveness to constrictor agonists might also occur through receptor mechanisms not involving []-adrenergic receptors, or through a non-receptor mechanism. Male rats were divided into sedentary (SED) and post-exercise (POST-EX) groups. The POST-EX group ran on a treadmill at 30 rn/min for one hour. Vasoconstrictor responses to potassium chloride (KCI, 10-100n1.M), PE (10 - 10 M), -9 -5 M determined on abdominal aortic and arginine vasopressin (AVP, 10 - 10 ) were rings in vitro in SED rats and immediately after a single bout of exercise in POST-EX rats. Vascular sensitivity of aortic rings to KCI and PE was not diminished after a single bout of exercise. Vascular tension evoked by AVP was greater in vessels from POST- EX rats. Since there was no diminished vascular sensitivity to receptor and non-receptor-mediated vasoconstrictor agonists, a time course study was performed in order to determine the duration of exercise training required to induce changes in vascular sensitivity to adrenergic stimulation. Male rats were divided into SED, POST-EX, 1 DAY, 1 WK, 2 WK, 4 WK., and 10 WK groups. Vascular responses to norepinephrine -9 10-4 M) were determined immediately after exercise in POST-EX rats and 24 'NE, 10 -hours after the last exercise bout in 1 DAY, 1 WK, 2 WK, 4 WK, and 10 WK rats. Sensitivity to NE was diminished in the 10 WK rats as compared to SED rats. This diminished vascular sensitivity to NE was abolished with removal of the endothelial. These data indicate that between 4 and 10 weeks of moderate- intensity exercise training diminishes vascular sensitivity to NE-mediated constriction, and this adaptation appears to be mediated through an endothelium-mediated mechanism. |
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| Item Description: | Vita. "Major subject: Kinesiology". |
| Physical Description: | viii, 27 leaves : illustrations ; 28 cm. |
| Bibliography: | Includes bibliographical references (leaves 23-26). |