Figure 4.

Fluorescent photomicrographs showing the co-localization neuronal nuclear (NeuN) marker and ethidium monoazide (EMA) in striatal neuron cultures at 24 h following exposure to medium alone (A), gp120 (500 pM) with or without Z-DEVD-FMK (DEVD) (50 µM) (B,C), or DEVD alone (50 µM) (D). Cell cultures were incubated with DEVD for 4 h prior to exposure to gp120. gp120 treatment increased the proportion of dying neurons and the toxicity was prevented by co-administering DEVD (see Table 1). Viable NeuN immunofluorescence neurons (arrowheads) appear green and exclude EMA (red fluorescence) from their nuclei. Non-viable neurons (arrows) fail to exclude EMA (red) and their nuclei appear yellow. Tat (100 nM) was also assayed but showed no effect at 24 h (see Table 1). The large photomicrographs (right-side) are composite images of NeuN reactivity (upper left insets) and EMA (lower left insets); scale bar = 20 µm.