Prevention of NO-induced apoptotic phosphatidylserine translocation by caspase inhibition
CGC were incubated with GSNO for 2 hr before they were stained with FITC-annexin V and H-33342 and imaged by confocal microscopy. The top panel shows an xy-section through the cell bodies (4 µm from coverslip). Apoptotic nuclei appear condensed and hyperfluorescent and are surrounded by annexin V-stained membranes. A transversal section (xz-plane) demonstrates that the entire surface of the apoptotic neurons plus some nonchromatin-containing blebs formed from the axonal projections are surface-stained with annexin V. Neurons that had been preincubated with z-D-cbk did not condense and did not stain with annexin V (preincubation somata). The axonal net (0.7 µm from cover-slip) of neurons protected by z-D-cbk stained focally with annexin V, possibly suggesting synaptic activity (preincubation-net). CGC that were challenged with GSNO and received z-D-cbk only during the last 30 min of the incubation were not protected and stained positively with annexin V (postincubation).