Sympathetic Cardiac Influence and Arterial Blood Pressure Instability

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dc.contributor.advisorShi, Xiangrong
dc.contributor.committeeMemberDowney, H. Fred
dc.contributor.committeeMemberGwirtz, Patricia A.
dc.creatorFormes, Kevin John
dc.date.accessioned2019-08-22T19:33:49Z
dc.date.available2019-08-22T19:33:49Z
dc.date.issued2002-09-01
dc.date.submitted2014-01-25T06:13:34-08:00
dc.description.abstractFormes, Kevin John, Sympathetic Cardiac Influence and Arterial Blood Pressure Instability. Master of Science (Biomedical Sciences) September 2002, 51 pp., 3 tables, 5 illustrations, 36 references. This study was designed to determine the role of β1-adrenoreceptors in arterial blood pressure (ABP) regulation during an orthostatic challenge. Metoprolol was used to block β1-adrenoreceptors. Atropine, a peripheral and central acting muscarinic blocker, was used to inhibit vagal influences on heart rate. Lower body negative pressure (LBNP) was used to stimulate an orthostatic hypotensive stimulus before and after receptor blockade. Metoprolol administration significantly increased baroreflex sensitivity (BRS) and significantly decreased the reflex increase baroreflex sensitivity (BRS) and significantly decreased the reflex increase in plasma renin activity (PRA) in response to a hypotensive stimulus. Therefore we suggest that the attenuation of PRA is counterbalanced by an increased heart rate reserve, which allows the heart rate to increase more in response to decreases in venous return. This increase in cardiac responsiveness was abolished with the administration of atropine. Therefore, we conclude that acute administration of metoprolol causes (i) improved ABP stability, as indicated by a diminished augmentation of low frequency (LF) ABP variability and (ii) attenuates the increase in PRA during LBNP induced central hypovolemic challenge.
dc.format.mimetypeapplication/pdf
dc.identifier.urihttps://hdl.handle.net/20.500.12503/26236
dc.language.isoen
dc.provenance.legacyDownloads0
dc.subjectCardiology
dc.subjectCardiovascular System
dc.subjectCirculatory and Respiratory Physiology
dc.subjectLife Sciences
dc.subjectMedical Physiology
dc.subjectMedical Sciences
dc.subjectMedicine and Health Sciences
dc.subjectSystems and Integrative Physiology
dc.subjectSympathetic cardiac influence
dc.subjectarterial blood pressure
dc.subjectinstability
dc.subjectβ1-adrenoreceptors
dc.subjectatropine
dc.subjectmetoprolol
dc.subjectABP
dc.subjectorthostatic challenge
dc.subjectplasma renin activity
dc.subjectlower body negative pressure
dc.subjectPRA
dc.subjectLBNP
dc.subjectcentral hypovolemic challenge
dc.subjectbaroreflex sensitivity
dc.subjectheart rate
dc.titleSympathetic Cardiac Influence and Arterial Blood Pressure Instability
dc.typeThesis
dc.type.materialtext
thesis.degree.departmentGraduate School of Biomedical Sciences
thesis.degree.disciplineBiomedical Sciences
thesis.degree.grantorUniversity of North Texas Health Science Center at Fort Worth
thesis.degree.nameMaster of Science

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