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In vivo assessment of resting and catecholamine stimulated cardiac function in rat models of low and high aerobic running capacity
Author(s) -
Morgan Eric E.,
Ways Justin A.,
Cicila George T.
Publication year - 2008
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.22.1_supplement.970.36
Subject(s) - medicine , dobutamine , cardiac function curve , endocrinology , catecholamine , contractility , basal (medicine) , stroke volume , in vivo , cardiac output , chemistry , heart rate , hemodynamics , blood pressure , biology , heart failure , microbiology and biotechnology , insulin
Our laboratory has previously identified inbred rat strains divergent for aerobic running capacity (ARC); low performing Buffalo (BUF) and high performing DA rats. Subsequent studies of isolated DA and BUF hearts showed a strong correlation between ARC and cardiac output (CO). In the present study, we tested the hypotheses that 1) there is increased in vivo basal LV function in DA compared with BUF rats and 2) the cardiac response to catecholamine stress is increased in DA vs. BUF rats. A high‐fidelity microtip pressure‐volume catheter was used to examine cardiac function in intact male BUF (n=13) and DA (n=12) rats at rest and during dobutamine infusion. Resting DA hearts outperformed BUF hearts as evidenced by a significantly higher cardiac output (39±2 vs 63±6 mL/min, P<0.05) and contractility index (136±4 vs 154±7 mmHg 2 /sec, P<0.05). Following dobutamine infusion (10μg/kg/min), CO was significantly greater in DA compared to BUF rats (50±2 vs 92±9 mL/min, P<0.05). DA rats showed a greater increase in stroke volume whereas BUF rats displayed a greater increase in heart rate following dobutamine infusion (Figure). We conclude that cardiac function is greater at rest in DA compared to BUF rats, and that DA and BUF hearts differ in their response to catecholamine stress. This work was supported by NIH grant HL67276 (GTC) and a Medical Student Research Fellowship from The University of Toledo College of Medicine (EEM).