Figure 5.
![Figure 5. Resetting of [Ca2+]mito (black) for two Ca2+ additions. 2 µM Ca2+ was first added to initiate mitochondrial Ca2+ uptake. 25 µM EGTA was added to decrease the extramitochondrial calcium concentration ([Ca2+]out, green) to the submicromolar range, and another 4 µM Ca2+ was added to evoke a second [Ca2+]mito response. A decrease in [Ca2+]mito upon lowering [Ca2+]out occurred only in the presence of Na+. Conditions: (A) zero NaCl; (B) 15 mM NaCl; (C) 15 mM NaCl plus 100 nM Ru360; (D) 15 mM NaCl plus 2 mM MgATP.](https://cdn.rupress.org/rup/content_public/journal/jgp/139/6/10.1085_jgp.201210784/4/jgp_201210784_fig5.jpeg?Expires=1773554310&Signature=fpP-hpxtfglijqrIzLPXD21iDWfJo7tBReTdu0KqnsxZWbeQzvC1hIko5JN219k1N3PwQEDaVPEo1zQl-MVcPU-JckHm7Uv-LSZLWizOVlk1QH0B5pG1gaq8nkYZoFyIzXDWZSYY48ngNFfjvoIStSIpd1WmczBWTx0zBMEydvK-d9SHH~wKBhftQX9Bg-1CPkimOmcvnvVJR62DKuiKD1V53P2ovhysmFkvOxfaelfk8LGAzdKb2BM8S~-zK6ITHWiJO7w7baAd89ORx152dNRKqZ8~j4e13r821yK5AZIoil7svpKCO4Drj9zeQtEos3GxYbANsq7rRqa8j94HVg__&Key-Pair-Id=APKAIE5G5CRDK6RD3PGA)
Resetting of [Ca2+]mito (black) for two Ca2+ additions. 2 µM Ca2+ was first added to initiate mitochondrial Ca2+ uptake. 25 µM EGTA was added to decrease the extramitochondrial calcium concentration ([Ca2+]out, green) to the submicromolar range, and another 4 µM Ca2+ was added to evoke a second [Ca2+]mito response. A decrease in [Ca2+]mito upon lowering [Ca2+]out occurred only in the presence of Na+. Conditions: (A) zero NaCl; (B) 15 mM NaCl; (C) 15 mM NaCl plus 100 nM Ru360; (D) 15 mM NaCl plus 2 mM MgATP.
