to clarify the cause of uncoupling of ca influx through ca channels and the contractility of the myocardium in hibernating chipmunks , the electromechanical effects of two different internal ca store inhibitors , caffeine and ryanodine , and a cardiotonic agent , isoprenaline , were investigated in papillary muscles of hibernating animals .
C0027061
myocardium
C0030352
papillary muscles