Figure 2.

Ca²⁺ handling and Δψ_m in STHdh cells without active glycolysis. Q7 cells (top panel; A–C) and Q111 cells (bottom panel; D–F) were loaded with fura-4F and Rh123 and assayed in the absence of glucose, in buffer containing 10 mm pyruvate and 2 mm DDG. Where indicated, the following drugs were added: 7 μm 4Br-A23187 (Br), 2 μg/ml oligomycin (O), 1 μm FCCP (F), and 2 μm rotenone (R). Maximal (M) and minimal (m) Ca²⁺ signals were used to normalize fura-4F ratios of individual cells; the right yy-axis is an approximation (see Materials and Methods). A–F, i, Individual Ca²⁺ responses of 10 representative cells; ii, individual changes in Rh123 whole-cell F′/F₀ fluorescence ratios for the same single cells; iii, average change in Rh123 fluorescence (cells collapsing Δψ_m before oligomycin in Aii and Dii were excluded from the averaging) in the nuclear area (thin line), in comparison with the average change in whole-cell Rh123 fluorescence (dotted line). In each individual experiment, 40–100 random single cells were analyzed; only 10 are shown for clarity but are representative of n = 3–5 independent experiments. See Results for a detailed description of the individual tracings.