Myocardial function in rat genetic models of low and high aerobic running capacity.
We recently evaluated treadmill aerobic running capacity in 11 inbred strains of rats and found that isolated working left ventricular function correlated (r = 0.86) with aerobic running capacity. Among these 11 strains the Buffalo (BUF) hearts produced the lowest and the DA hearts the highest isolated cardiac output. The goal of this study was to investigate the components of cardiac function (i.e., coronary flow, heart rates, stroke volume, contractile dynamics, and cross-bridge cycling) to characterize further the BUF and DA inbred strains as potential models of contrasting myocardial performance. Cardiac performance was assessed using the Langendorff-Neely working heart preparation. Isolated DA hearts were superior (P < 0.05) to the BUF hearts for cardiac output (63%), stroke volume (60%), aortic +dP/dt (47%), and aortic -dP/dt (46%). The mean alpha/beta-myosin heavy chain (MHC) isoform ratio for DA hearts was 21-fold higher relative to BUF hearts. At the steady-state mRNA level, DA hearts had a fivefold higher alpha/beta-ratio than the BUF hearts. The mean rate of ATP hydrolysis by MHCs was 64% greater in DA compared with BUF ventricles. These data demonstrate that the BUF and DA strains can serve as genetic models of contrasting low and high cardiac function.
Barbato
John C
JC
Functional Genomics Laboratory, Medical College of Ohio, Toledo, Ohio 43614-5804, USA.
Lee
Soon Jin
SJ
Koch
Lauren Gerard
LG
Cicila
George T
GT
D000255:Adenosine Triphosphate / Q000378:metabolism; D000332:Aerobiosis; D000818:Animals; D001011:Aorta / Q000502:physiology; D001794:Blood Pressure; D002302:Cardiac Output; D006706:Homeostasis; D006868:Hydrolysis; D066298:In Vitro Techniques; D009043:Motor Activity / Q000502:physiology*; D009206:Myocardium / Q000378:metabolism; D018995:Myosin Heavy Chains / Q000235:genetics / Q000378:metabolism; D010807:Physical Endurance / Q000235:genetics* / Q000502:physiology*; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D011915:Rats, Inbred BUF; D011919:Rats, Inbred Strains; D013318:Stroke Volume; D016277:Ventricular Function, Left / Q000502:physiology*
D020033:Protein Isoforms; D012333:RNA, Messenger; D000255:Adenosine Triphosphate; D018995:Myosin Heavy Chains