Interaction of Neural and Local Mechanisms in the Control of Skeletal Muscle Blood Flow
dc.contributor.advisor | Michael L. Smith | |
dc.creator | Wray, David Walter | |
dc.date.accessioned | 2019-08-22T19:43:23Z | |
dc.date.available | 2019-08-22T19:43:23Z | |
dc.date.issued | 2003-12-01 | |
dc.date.submitted | 2013-11-15T14:00:28-08:00 | |
dc.description.abstract | Wray, David Walter, Interaction of Neural and Local Mechanisms in the Control of Skeletal Muscle Blood Flow. Doctor of Philosophy (Biomedical Science), December, 2003, 181 pp., 1 table, 19 illustrations, references, 139 titles. The current project sought to characterize the interaction of neural and local mechanisms of skeletal muscle blood flow control through exogenous and endogenous α-andrenoreceptor activation. We hypothesized that α1- and α2-adrenoreceptors in the human leg would exhibit differential distribution and responsiveness, and that unilateral knee-extensor exercise would attenuate α-adrenoreceptor-mediated vasoconstriction in an intensity-dependent manner. We also hypothesized that carotid baroreflex (CBR)-mediated sympathoexcitation would provoke less vasoconstriction during exercise than at rest. Intra-arterial infusion of phenylephrine (PE, α1-agonist) or BHT-933 (α2-agonist) reduced femoral blood flow (FBF) by approximately 60% at rest, but during exercise (27W) the degree of vasoconstriction evoked by PE and BHT was significantly reduced. During ramped (7W-37W) exercise, BHT did not reduce FBF at any intensity, while some degree of PE-induced vasoconstriction was evident at all but the highest exercise intensity. Using sinusoidal neck pressure, CBR-mediated changes in heart rate (HR), arterial blood pressure (ABP) muscle sympathetic nerve activity (MSNA), FBF, and tissue oxygenation (TOm) were seen at rest. During 7w exercise, CBR-mediated control of ABP, FBF, and Tom was attenuated. We conclude that exercise attenuates α-adrenergic responsiveness to exogenous and endogenous activation to ensure sufficient muscle blood flow while maintaining systemic ABP homeostasis. | |
dc.format.mimetype | application/pdf | |
dc.identifier.uri | https://hdl.handle.net/20.500.12503/26824 | |
dc.language.iso | en | |
dc.provenance.legacyDownloads | 0 | |
dc.subject | Cardiology | |
dc.subject | Genetics | |
dc.subject | Genetics and Genomics | |
dc.subject | Medical Genetics | |
dc.subject | Neurology | |
dc.subject | Cardiology | |
dc.subject | leg | |
dc.subject | exercise | |
dc.subject | blood flow | |
dc.title | Interaction of Neural and Local Mechanisms in the Control of Skeletal Muscle Blood Flow | |
dc.type | Dissertation | |
dc.type.material | text | |
thesis.degree.department | Graduate School of Biomedical Sciences | |
thesis.degree.grantor | University of North Texas Health Science Center at Fort Worth | |
thesis.degree.name | Doctor of Philosophy |
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