Effect of T-type Ca2+ channel activation on [Ca2+]mit and [Ca2+]cyt.
A, [Ca2+]mit responses evoked by the addition of 20 mm K+ to naïve and Cav3.1/Cav3.2-depleted cells. Cav3.1/Cav3.2 silencing significantly decreased the amplitude of the [Ca2+]mit response. B, [Ca2+]cyt responses recorded under the same conditions. C, [Ca2+]mit responses evoked by the addition of 100 μm ATP to evoke rapid Ca2+ release from intracellular stores. D, [Ca2+]mit responses evoked by the addition of thapsigargin followed by Ca2+ readmission to promote Ca2+ entry across store-operated Ca2+ entry channels. Cav3.1/Cav3.2 silencing had no effect on the mitochondrial Ca2+ responses associated with ER Ca2+ release or store-operated Ca2+ entry-mediated Ca2+ influx. Data are mean ± S.E. from three to six independent recordings. The total number of measured cells is indicated inside the bars. ns, non-significant; **, p < 0.01 (Student's t test for unpaired samples).