Date of Award

1998

Degree Type

Thesis

Degree Name

M.H.K.

Department

Kinesiology

First Advisor

Kenno, K.

Keywords

Biology, Animal Physiology.

Rights

CC BY-NC-ND 4.0

Abstract

The purpose of this study was to examine: (1) if chronic swim training improves cardiac performance, (2) if chronic swim training alters sarcoplasmic reticulum (SR) calcium (Ca2+) storage, the fractional release (FR) of SR Ca2+ and SR Ca2+ uptake during relaxation and (3) if exercise training alters the handling of an increase in extracellular Ca2+ load in cardiac muscle. Chronic swim training produced a significant increase in the peak developed tension (PDT)) and in the maximum rates of contraction and relaxation in cardiac muscle. Utilizing rapid cooling contractures we found that improvements in cardiac performance were associated with significant increases in both SR Ca2+ stores and FR of SR Ca2+ in the exercised animals. The fraction of cytoplasmic Ca2+ removed by the SR during relaxation was not altered by swim training. However, the significant increase in SR Ca2+ content in the exercised animals suggests an increase in the absolute amount of SR Ca2+ uptake during relaxation in these animals. Elevating the extracellular Ca2+ concentration ([Ca 2+]o) led to an increase in PDT, SR Ca2+ storage, and FR of SR Ca2+ in both the sedentary and exercised groups. In the exercise group elevating [Ca2+]o had a more significant effect on cardiac muscle PDT but a less significant effect on SR Ca2+ storage and FR compared to the sedentary group. In summary chronic swim training improved cardiac performance by increasing both the total SR Ca2+ available for release and the fraction of this SR Ca2+ that is released during contraction. Exercise training also altered the inotropic; response of cardiac muscle to an increase in [Ca2+]o.Dept. of Kinesiology. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1997 .Q4. Source: Masters Abstracts International, Volume: 39-02, page: 0437. Adviser: Kenji Kenno. Thesis (M.H.K.)--University of Windsor (Canada), 1998.

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