REDUCTION IN THE CONTRACTION AND INTRACELLULAR CALCIUM TRANSIENT OF SINGLE-RAT VENTRICULAR MYOCYTES BY GADOLINIUM AND THE ATTENUATION OF THESE EFFECTS BY EXTRACELLULAR NAH2PO4

Gadolinium (Gd3+) is the most commonly used blocker of stretch-activated channels (SACs). The actions of Gd3+ in unstretched adult heart were investigated by observing its effects on the contraction and intracellular calcium transient of single rat ventricular myocytes. We found that Gd3+ caused a profound reduction in both these parameters at doses typically used to block SACs. However, the actions of Gd3+ were severely attenuated by the presence of 0.33 mM NaH2PO4, which possibly chelates the Gd3+ ion.