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Cardiac performance in inbred rat genetic models of low and high running capacity
Author(s) -
Chen J.,
Feller G. M.,
Barbato J. C.,
Periyasamy S.,
Xie Z.J.,
Koch L. G.,
Shapiro J. I.,
Britton S. L.
Publication year - 2001
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1111/j.1469-7793.2001.00611.x
Subject(s) - medicine , aerobic capacity , inbred strain , endocrinology , papillary muscle , endoplasmic reticulum , myocyte , biology , calcium , treadmill , cardiac function curve , chemistry , heart failure , gene , microbiology and biotechnology , genetics
1 Previous work demonstrating that DA inbred rats are superior to COP inbred rats in aerobic treadmill running capacity has indicated their utility as genetic models to explore this trait. We tested the general hypothesis that intermediate phenotypes of cardiac function and calcium metabolism are responsible for the difference in capacity between these strains. 2 Logical cardiac trait differences were estimated at a tissue (isolated papillary muscle), cellular (isolated left ventricular cells), and biochemical level of organization. 3 DA hearts were found to give significantly higher values than COP hearts for: (1) maximal developed tension (38.3 % greater), and rates of tension change in contraction (61 %) or relaxation (59 %) of isolated papillary muscle, (2) fractional shortening (50 %), amplitude of the Ca 2+ transient (78.6 %), and caffeine‐induced release of Ca 2+ from the sarcoplasmic reticulum (SR; 260 %) in isolated ventricular myocytes, and (3) Na + ,K + ‐ATPase activity of isolated myocytes (17.3 %). 4 Our results suggest that these trait differences may prove useful for further studies into the genes responsible for natural variations in both ventricular function and aerobic endurance capacity. Understanding the genetic basis of aerobic capacity will help define the continuum between health and disease.