Figure 6.

Oxidant treatment induces neurite degeneration. A, Titer series of the oxidant H₂O₂ demonstrates minimal neurite degeneration at day 3 after treatment with H₂O₂ concentrations of <100 μm applied selectively to neurites. Substantial neurite degeneration is observed with 250 μm H₂O₂ and nearly complete degeneration is exhibited by neurites administered 500 μm H₂O₂. B, Across-treatment-group comparisons demonstrate that blockade of sodium channels with TTX (0.3 μm) does not provide protection from 350 μm H₂O₂-induced neurite degeneration at day 3 or day 6 (not significant, n.s.; n = 12 compartments each for H₂O₂ and H₂O₂ + TTX conditions, respectively). Treatment of neurites with 500 μm H₂O₂ induced greater degeneration than 350 μm H₂O₂ and neurite degeneration was not protected by TTX treatment at day 3 or day 6 (not significant, n.s.; n = 6 and 7 compartments each for H₂O₂ and H₂O₂ + TTX conditions, respectively). Neurite lengths are normalized to pretreatment lengths (pre) for each individual neurite compartment at days 3 and 6, respectively. Data are presented as mean ± SEM.