A, Example images of hippocampal neurons co-transfected with Mito-mKate2 and VGlut1pHluorin before and during field stimulation. The white arrow indicates a terminal occupied with a mitochondrion, while the empty arrow indicates a terminal without a mitochondrion. B, Average traces of presynaptic terminals of hippocampal neurons transfected with VGlut1pHluorin and Mito-mKate2 and stimulated using field stimulation at 10 Hz for 20s (40-60s). Terminals with a mitochondrion are represented by the red trace and terminals without are represented by the black trace. C, Summary graph corresponds to the traces shown in panel B). Mean stimulation fluorescence (time points 60-70s) comparing terminals of the same axon which contain mitochondria (right, ΔF/F0 = 2.3 0.9) compared to terminals without mitochondria (left, ΔF/F0 = 3.2 0.7) (n=9 neurons, 66 terminals, *p<0.05, paired t-test). Experiments performed in P0 rat hippocampal neuronal cultures at DIV 10-12. Error bars represent SEM. 