ABSTRACT
The aim of the present study was to evaluate the Ca2+ handling and contractility properties of cardiomyocytes isolated from rats with high intrinsic aerobic exercise capacity. Standard-performance (SP) and high-performance (HP) rats were categorized with a treadmill progressive exercise test according to the exercise time to fatigue (TTF). The SP group included rats with TTF between 16.63 and 46.57 min, and the HP group included rats with TTF>46.57 min. Isolated ventricular cardiomyocytes were dissociated from the hearts of SP and HP rats, and intracellular global Ca2+ ([Ca2+]i) transients were measured. The [Ca2+]i transient peak was increased in the HP group relative to the SP group (5.54+/-0.31 vs. 4.18+/-0.12 F/F0; PSubject(s)
Calcium Signaling
, Exercise Tolerance
, Heart Ventricles/metabolism
, Myocardial Contraction
, Myocytes, Cardiac/metabolism
, Physical Exertion
, Animals
, Calcium-Binding Proteins/metabolism
, Kinetics
, Male
, Muscle Fatigue
, Rats
, Rats, Wistar
, Ryanodine Receptor Calcium Release Channel/metabolism
, Sarcoplasmic Reticulum Calcium-Transporting ATPases/metabolism
, Sodium-Calcium Exchanger/metabolism
, Time Factors
