Superoxide anions mediate veratridine-induced cytochrome c release and caspase activity in bovine chromaffin cells.
1. Mitochondrial mechanisms involved in veratridine-induced chromaffin cell death have been explored. 2. Exposure to veratridine (30 micro M, 1 h) produces cytochrome c release to the cytoplasm that seems to be mediated by superoxide anions and that is blocked by cyclosporin A (10 micro M), MnTBAP (10 nM), catalase (100 IU ml(-1)) and vitamin E (50 micro M). 3. Following veratridine treatment, there is an increase in caspase-like activity, blocked by vitamin E (50 micro M) and the mitochondrial permeability transition pore blocker cyclosporin A (10 micro M). 4. Superoxide anions open the mitochondrial permeability transition pore in isolated mitochondria, an effect that is blocked by vitamin E (50 micro M) and cyclosporin A (10 micro M), but not by the Ca2+ uniporter blocker ruthenium red (5 micro M). 5. These results strongly suggest that under the stress situation caused by veratridine, superoxide anions become important regulators of mitochondrial function in chromaffin cells. 6. Exposure of isolated bovine chromaffin mitochondria to Ca2+ results in mitochondrial swelling. This effect was prevented by ruthenium red (5 micro M) and cyclosporin A (10 micro M), while it was not modified by vitamin E (50 micro M). 7. Veratridine (30 micro M, 1 h) markedly decreased total glutathione and GSH content in bovine chromaffin cells. 8. In conclusion, superoxide anions seem to mediate veratridine-induced cytochrome c release, decrease in total glutathione, caspase activation and cell death in bovine chromaffin cells.
Jordán
Joaquín
J
Centro Regional de Investigaciones Biomédicas y Dpto Ciencias Médicas, Facultad de Medicina, Universidad de Castilla-La Mancha, Albacete, Spain.
Galindo
María F
MF
Tornero
Daniel
D
Benavides
Amparo
A
González
Constancio
C
Agapito
María T
MT
González-García
Carmen
C
Ceña
Valentín
V
D000111:Acetylcysteine / Q000494:pharmacology; D000818:Animals; D019328:Buthionine Sulfoximine / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology; D020169:Caspases / Q000378:metabolism*; D002374:Catalase / Q000494:pharmacology; D002417:Cattle; D002470:Cell Survival / Q000187:drug effects; D019439:Chromaffin Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D016572:Cyclosporine / Q000494:pharmacology; D003574:Cytochrome c Group / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D005978:Glutathione / Q000378:metabolism; D008665:Metalloporphyrins / Q000494:pharmacology; D008928:Mitochondria / Q000187:drug effects / Q000502:physiology; D010539:Permeability / Q000187:drug effects; D013481:Superoxides / Q000378:metabolism*; D014701:Veratridine / Q000494:pharmacology*; D014810:Vitamin E / Q000494:pharmacology
D003574:Cytochrome c Group; D008665:Metalloporphyrins; C097284:manganese(III)-tetrakis(4-benzoic acid)porphyrin; D013481:Superoxides; D014810:Vitamin E; D019328:Buthionine Sulfoximine; D014701:Veratridine; D016572:Cyclosporine; D002374:Catalase; D020169:Caspases; D005978:Glutathione; D002118:Calcium; D000111:Acetylcysteine