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osu1078942640.pdf (2.01 MB)
ETD Abstract Container
Abstract Header
Exercise training effects on myocardial stunning
Author Info
Hwang, Hyosook
Permalink:
http://rave.ohiolink.edu/etdc/view?acc_num=osu1078942640
Abstract Details
Year and Degree
2004, Doctor of Philosophy, Ohio State University, Educational Services and Research.
Abstract
It was the purpose of this study to investigate effects of exercise training on post-ischemia/reperfusion (I/R) contractile function. I/R induced significant contractile dysfunction in hearts from sedentary control animals; left ventricular developed pressure (LVDP) and maximal rate of pressure development and relaxation (±dP/dt) decreased, while end-diastolic pressure (EDP) increased. However, this dysfunction was attenuated in the myocardium from exercise-trained animals (LVDP, sedentary -60.8 ± 6.4%, vs. trained -15.6 ± 8.6%; +dP/dt, sedentary -54.1 ± 4.7%, vs. trained -16.7 ± 8.4%; -dP/dt, sedentary -44.4 ± 2.5%, vs. trained -17.9 ± 7.2%; EDP, sedentary 539.5 ± 147.6%, vs. trained 71.6 ± 30.6%). In contrast, exercise training did not alter Troponin I (TnI) degradation and level of myocardial adenine nucleotide, such that I/R reduced myocardial ATP and ADP levels to a similar extent in both sedentary and trained animals. Exercise training increased the amplitude of Ca2+ transients and the maximal rate of Ca2+ decline. The maximal normalized isometric force measured in isolated, skinned ventricular trabeculae (force/cross-sectional area; P0/CSA) was increased by an average 26% in trained trabeculae (25.8 ± 1.6 kN/m2), compared to controls (20.5 ± 1.3 kN/m2) and this increase was not affected by ischemia/reperfusion. Exercise training had no effect on maximal shortening velocity (V0); in contrast, I/R reduced V0 by 34% in both control and trained trabeculae (2.64 ± 0.15 vs. 1.74 ± 0.17 trabecula lengths/sec). Exercise training increased the expression of the beta isoform of myosin heavy chain (MHC-beta) in trabeculae, as well as, in the ventricular free wall. Thus, despite the similar degree of ischemic response shown as a reduction in myocardial adenine nucleotide and V0 and proteolytic damage to TnI, myocardium from exercise-trained animals had better contractile functional recovery following a brief period of ischemia. The potential adaptive factors that might contribute to this improvement in contractile function include an enhanced Ca2+ handling mechanism, an increase in P0/CSA, and a possible increase in the economy, as inferred from increased expression of MHC-beta.
Committee
George Billman (Advisor)
Pages
132 p.
Keywords
Myocardial stunning
;
Exercise training
;
Ischemia/reperfusion
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Citations
Hwang, H. (2004).
Exercise training effects on myocardial stunning
[Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1078942640
APA Style (7th edition)
Hwang, Hyosook.
Exercise training effects on myocardial stunning.
2004. Ohio State University, Doctoral dissertation.
OhioLINK Electronic Theses and Dissertations Center
, http://rave.ohiolink.edu/etdc/view?acc_num=osu1078942640.
MLA Style (8th edition)
Hwang, Hyosook. "Exercise training effects on myocardial stunning." Doctoral dissertation, Ohio State University, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=osu1078942640
Chicago Manual of Style (17th edition)
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Document number:
osu1078942640
Download Count:
1,646
Copyright Info
© 2004, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.