Figure 3.

Mitochondrial respiratory chain (MRC) is functional but not activated by glutamate in astrocytes knocked-down for GC1. (A) Relative mitochondrial membrane potential (∆ψm) was assessed in transfected astrocytes (red, left, white arrow) loaded with Rhodamine 123 (R123, green, middle) in a medium containing low glucose (0.5 mM, resting condition). (B) Mitochondrial membrane hyperpolarization was elicited by addition of 1 mM glutamate (Glu, black arrow) and by 15.5 mM Glucose (Glc, white arrow). Control depolarization was assessed with the uncoupler Carbonyl cyanide-4-(trifluoromethoxy)phenylhydrazone (FCCP; 1 μM, gray arrow). Measurements were made in control astrocytes (white squares, n = 28), transfected with shRNA-GC1 (black circles, n = 23) or in the presence of DL-TBOA (gray diamonds, n = 29). Data are normalized with the resting condition and expressed as means ± SEM at each time point. (C) Area under normalized curves was measured after each stimulation in control astrocytes in the presence or not of DL-TBOA, in astrocytes transfected with shRNA-GC1 or mmRNA (n = 12). Data are expressed as mean ± SEM. Kruskal-Wallis followed by Dunn test. Experiments were performed with 4–10 independent transfections, derived from 10 individual astrocyte cultures.