Figure 1.

Mitochondria in myelinated and demyelinated axons of DRG neurons. A, Representative live imaging of myelinated DRG cultures infected by mito-DsRed2 lentivirus. An asterisk shows the cell body of a DRG neuron. The arrows indicate predicted nodes of Ranvier. Mitochondria labeled by fluorescent red are distributed in the axon as well as the cell body. Note that surrounding Schwann cells are not labeled. B, Colabeling of mitochondria with DsRed2 (red), Na⁺ channel (green), and MBP (blue) by immunostaining. C, An electron micrograph of a myelinated DRG axon. Multiple elongated mitochondria were clustered at single sites (arrowhead); their spatial separation and cristae are visible at higher magnification (inset). This arrangement of mitochondria establishes that many mitochondrial stationary sites contain multiple mitochondria. D–I, Myelination and demyelination in DRG cultures. Immunostaining of MBP (green) and neurofilament (NF) (red) in control culture (D–F) and culture 2 d after lysolecithin (Lyso) treatment (G–I). The insets show magnified images of the areas marked with rectangles in F and I. Note that continuous MBP-positive myelin sheath in control (D–F) becomes discontinuous and fragmented after Lyso treatment (G–I). Scale bars: C, 500 nm; C, inset, 250 nm; others, 10 μm.