Figure 3.

Prolongation of Ca²⁺ clearance by blockade of mitochondrial energization or of the mitochondrial uniporter. (A–B) Time course of cytoplasmic [Ca²⁺] monitored with indo-1 (100 μM) introduced into the cytosol by inclusion in the pipette solution alone (A) or, in a different cell, together with 2 μM RR (B). Beginning 3–5 min after the wholecell patch-clamp configuration was established, dual emission fluorescence signals were recorded. One or two 500–600-ms depolarizing pulses were applied (arrows) while each cell was perfused with control medium alone. Another one or two pulses were applied after 2 μM CCCP was included in the perfusion medium. (C– D) Effect of mitochondrial inhibitors on clearance of submembrane Ca_c as measured by the decay (tail) of a Ca²⁺-activated K⁺ current. Tail currents were recorded in perforated-patch configuration in response to 1-s depolarizations to 0 mV applied every 2 min (Park, 1996). After 9.5 min, the perfusion medium was supplemented with 3 μM oligomycin or 5 mM NaCN and at 11.5 min, with both. (D) Peak amplitude and half-decay times of currents observed after treatment were normalized to those obtained in the preceding control stimulus applied to the same cell. The numbers of cells examined are shown in parentheses.