Veratridine induces apoptotic death in bovine chromaffin cells through superoxide production

1 The molecular mechanisms involved in veratridine-induced chromaffin cell death have been explored. 2 We have found that exposure to veratridine (30 mu M, 1 h) produces a delayed cellular death that reaches 55% of the cells 24 h after veratridine exposure. This death has the features of apoptosis as DNA fragmentation can be observed. 3 Calcium ions play an important role in veratridine-induced chromaffin cell death because the cell permeant Ca2+ chelator BAPTA-AM and extracellular Ca2+ removal completely prevented veratridine-induced toxicity. 4 Following veratridine treatment, there is a decrease in mitochondrial function and an increase in superoxide anion production. Veratridine-induced increase in superoxide production was blocked by tetrodotoxin (TTX; 10 mu M), extracellular Ca2+ removal and the mitochondrial permeability transition pore blocker cyclosporine A (10 mu M). 5 Veratridine-induced death was prevented by different antioxidant treatments including catalase (100 IU ml(-1)), N-acetyl cysteine (100 mu M), allopurinol (100 mu M) or vitamin E (50 mu M). 6 Veratridine-induced DNA fragmentation was prevented by TTX (10 mu M). 7 Veratridine produced a time-dependent increase in caspase activity that was prevented by Ca2+ removal and TTX (10 mu M). In addition, calpain and caspases inhibitors partially prevented veratridine-induced death. 8 These results indicate that chromaffin cells share with neurons the molecular machinery involved in apoptotic death and might be considered a good model to study neuronal death during neurodegeneration.