Fig. 6.

Delayed Ca²⁺ deregulation induced in a subpopulation of cells by release of matrix Ca²⁺ into the cytoplasm occurs in the absence of previous mitochondrial dysfunction. The 7 DIV granule cells were loaded with fura-2 and equilibrated with 50 nmTMRM⁺. The cells were exposed to 100 μm glutamate/10 μm glycine (G); 2 μg/ml oligomycin (O) and 1 μm FCCP (F) were added where indicated. The traces represent the fura-2 (filled circles trace) and TMRM⁺ (smooth trace) responses from a single representative soma. A, Cell that regains cytoplasmic Ca²⁺ homeostasis after FCCP. The FCCP-induced fura-2 spike occurs during release of matrix Ca²⁺ and its subsequent removal from the cytoplasm. Note the oligomycin-induced fluorescent quenching diagnostic of mitochondrial ATP synthesis before the inhibitor addition.B, Cell that fails to restore a low [Ca²⁺]_c after FCCP. Note that the mitochondria in this cell also generated ATP before the oligomycin addition.