Effects of Nitric Oxide on Right Ventricular Metabolism and Coronary Blood Flow

Simple item page
dc.contributor.advisorH. Fred Downey
dc.contributor.committeeMemberPatricia A. Gwirtz
dc.contributor.committeeMemberJames L. Caffrey
dc.creatorSetty, Srinath
dc.date.accessioned2019-08-22T21:16:34Z
dc.date.available2019-08-22T21:16:34Z
dc.date.issued2000-01-09
dc.date.submitted2013-10-10T06:30:13-07:00
dc.description.abstractSetty, Srinath Varadaraj. Effects of Nitric Oxide on Right Ventricular Metabolism and Coronary Blood Flow Doctor of Philosophy (Biomedical Sciences), January, 9, 2001, 123 pp, 3 tables, 16 figures, references, 211 titles. Nitric oxide (NO) formed from L-arginine and released from vascular endothelium causes relaxation of vascular smooth muscle via a cGMP mechanism. However, the of NO as a regulator of coronary blood flow control is unclear. NO has been shown also to reduce oxygen consumption in various in-vitro preparations, but its effect on myocardial oxygen consumption (MVO2) in the left ventricle of the working heart is controversial. The effect of NO on MVO2 in the right ventricle (RV) is unknown. This investigation delineated the effects of NO on RV MVO2 during controlled systemic and coronary hemodynamic conditions. In open chest dogs, NO synthesis was blocked by intracoronary infusion of NO synthesis with Nω-nitro-L-arginine methyl ester (L-NAME, 150 μg/min). To avoid effects of NO synthesis blockade on right coronary blood flow (RCBF), which might have altered RV MVO2, experiments were conducted during adenosine-induced maximal right coronary vasodilation (n=12). RCBF, RV MVO2, and other variables were measured at baseline and at elevated right coronary perfusion pressures (RCP). Under these conditions, L-NAME significantly increased RV MVO2 at baseline and at elevated RCP (P [less than] 0.05 vs. untreated control condition). These results indicate that NO acts to retard RV oxidative metabolism. We further characterized the role of NO on RV MVO2 during increases in RV workload, estimated as a product of heart rate X RV peak systolic pressure X RV dP/dt. RV workload, RCBF, and RV MVO2 were increased by intracoronary norepinephrine infusions at baseline RCP (n=5). L-NAME significantly reduced RCBF (P [less than] 0.05 vs. untreated control condition), and RV MVO2 was significantly higher at any measured RV workload during L-NAME (P [less than] 0.05 vs. untreated control condition). These findings indicate that NO is an important component of RCBF control and that NO blunts norepinephrine-induced increase in RV MVO2. If NO reduced RV MVO2 it may be cardioprotective during moderate right coronary hypoperfusion. Thus, we sought to determine if in fact the RV MVO2 was reduced by NO during moderate right coronary hypoperfusion (n=9). RCP was reduced to 60 (n=5) and 40 mmHg (n=4), and RCBF and RV MVO2 fell as RCP was reduced. L-NAME significantly increased RV MVO2 at RCP of 60 and 40 mmHg (P [less than] 0.05 vs. untreated control condition), although RV workload was not altered. Since NO reduced RV MVO2 without compromising RV mechanical performance, RV oxygen utilization efficiency was enhanced. Taken together, these findings demonstrate that NO has a significant dampening effect on RV MVO2.
dc.format.mimetypeapplication/pdf
dc.identifier.urihttps://hdl.handle.net/20.500.12503/29208
dc.language.isoen
dc.provenance.legacyDownloads0
dc.subjectCardiovascular System
dc.subjectCirculatory and Respiratory Physiology
dc.subjectComparative and Laboratory Animal Medicine
dc.subjectExercise Physiology
dc.subjectLife Sciences
dc.subjectMedicine and Health Sciences
dc.subjectPhysiology
dc.subjectNitric Oxide
dc.subjectright ventricular metabolism
dc.subjectright coronary blood flow
dc.subjectL-arginine
dc.subjectmyocardial oxygen consumption
dc.subjectdogs
dc.titleEffects of Nitric Oxide on Right Ventricular Metabolism and Coronary Blood Flow
dc.typeDissertation
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.nameDoctor of Philosophy

Files

Original bundle

Now showing 1 - 1 of 1
Thumbnail Image
Name:
Setty_EffectsOfNitricOxide.pdf
Size:
42.89 MB
Format:
Adobe Portable Document Format
Download

Collections

School of Biomedical Sciences
Theses and Dissertations