Fig. 1. Mitochondria accumulate at sites of nerve growth factor (NGF) stimulation. Phase-contrast micrographs (A,C) and epifluorescent images of mitochondria stained with rhodamine 123 (R123) in living neurons (B,D) were used to compare the distribution of mitochondria in the axon adjacent to an NGF-coated bead (A,B) and a heat-denatured NGF-coated bead (C,D). Mitochondria accumulate at sites of bead–axon contact within 1 h. No mitochondrial accumulation is observed using the control heat-denatured NGF-coated beads. Scale bar, 10 µm.