Premium
Exercise enhances inotropic responsiveness of cardiac myocytes
Author(s) -
Galvin Amy,
Kohler Jacob,
FosterBey Lianna,
Kim JinSun,
Bailey Beth A.
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.711.9
Subject(s) - sarcomere , medicine , myocyte , inotrope , endocrinology , muscle hypertrophy , basal (medicine) , cardiac function curve , cardiac myocyte , cardiology , cardiac hypertrophy , chemistry , biology , heart failure , insulin
Exercise‐induced cardiac structural and functional remodeling has recently been shown to vary between the sexes. In this study we sought to examine the sex‐based differences in the cardiac remodeling after swim training. Methods Male and female Swiss Webster mice swam for 70 minutes two times daily for 4 weeks. Myocytes were isolated from control male (CM) and control female (CF) and swim‐trained male (STM) and swim‐trained female (STF) mice, field stimulated, and Fluo‐3 transients and sarcomere shortening were measured. Results Swim training resulted in significant cardiac hypertrophy in both males and females (16% and 12%, respectively). STF myocytes exhibited lower basal contractile properties (2Hz, 1.5mM Ca) compared to CF (% resting sarcomere length 4.5±.29% STF vs 7.1±.31% CF; fluo‐3 fluorescence 1.66±.04 STF vs 2.18±.09CF) while there were no differences between CM and STM contractile properties. Contractile reserve responses of myocytes were studied by application of isoproterenol (ISO, 10 −7 M). ISO caused a significantly greater increase in the contractile properties of STF (333±37%) and STM (325±39%) myocytes than in CF (209±13%) or CM (230±29%) myocytes. Conclusion Swim training induces physiological cardiac hypertrophy and causes increased contractile responses to catecholamines in both males and females which should enhance cardiac pump function during exercise.