Ca2+ sparks triggered by patch depolarization in rat heart cells

Abstract

The goal of this study was to examine the relationship between Ca2+ entry through L-type Ca2+ channels and local [Ca2+](i) transients (Ca2+ sparks) in single rat cardiac ventricular cells. L-type Ca2+ channels were activated by depolarization of cell-attached membrane patches, and [Ca2+](i) was measured simultaneously as fluo 3 fluorescence using laser scanning confocal microscopy. Patch depolarization with Ca2+ as the charge career (10 or 110 mmol · L-1) significantly increased the probability of the occurrence of Ca12+ sparks (Ca2+ spark rate) only in the volume of cytoplasm located immediately beneath the membrane patch (basal Ca2+ spark rate, 119 Ca2+ sparks · cell- · s-1; patch depolarization Ca2+ spark rate, 610 Ca2+ sparks · cell-1 · s-1; P