Link between P2X receptors and NCX in wild-type (WT) myocytes. A: 2-meSATP-induced increase of INCX in WT myocytes. Ni2+-sensitive currents before and after 2-meSATP application are shown at membrane potentials of −100, −80, 50, and 70 mV. INCX at +50 and +70 mV was significantly larger in the presence of 2-meSATP than under CTR conditions (n = 8 cells from 7 WT mice). *P < 0.05. B: percent increases of CS above basal during application of 2-meSATP plus ivermectin (Ive; percent above basal, n = 8 cells from 7 WT mice) and during the subsequent exposure of KBR plus 2-meSATP and Ive (percent above basal with KBR plus 2-meSATP and Ive vs. that with 2-meSATP plus Ive, P < 0.05).