Veratridine induces apoptotic death in bovine chromaffin cells through superoxide production

The molecular mechanisms involved in veratridine-induced chromaffin cell death have been explored. We have found that exposure to veratridine (30μM, 1h) produces a delayed cellular death that reaches 55% of the cells 24h after veratridine exposure. This death has the features of apoptosis as DNA fragmentation can be observed. 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. 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; 10μM), extracellular Ca2+ removal and the mitochondrial permeability transition pore blocker cyclosporine A (10μM). Veratridine-induced death was prevented by different antioxidant treatments including catalase (100IUml−1), N-acetyl cysteine (100μM), allopurinol (100μM) or vitamin E (50μM). Veratridine-induced DNA fragmentation was prevented by TTX (10μM). Veratridine produced a time-dependent increase in caspase activity that was prevented by Ca2+ removal and TTX (10μM). In addition, calpain and caspases inhibitors partially prevented veratridine-induced death. 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.This work has been supported in part by grants SAF96-0169 and 1FD97-0500 from CICYT and from Fundacion NavarroTripodi to V.Ceña and SAF98-0140 and 2FD97-0647 from CICYT to C.Gonzalez-Garcia; J.Jordan is a recipient of a Contrato de Reincorporacion from Ministerio de Educacion y Cultura, Spain. M.F. Galindo is a recipient of a fellowship from the University Miguel Hernandez.Peer reviewe