isolated rat ventricular cardiac myocytes loaded with the fluorescent calcium indicator fura2 showed significant changes in intracellular calcium concentrations upon exposure to greater than 1 microm atp ( ec50 = 7.4 +/- 1.3 microm , n = 4 , se ) , suggesting that extracellular atp may have an important influence on myocardial contractility .
C0225828
cardiac myocytes
C0027061
myocardial