Effects of Photofrin photodynamic action on mitochondrial respiration and superoxide radical generation.
Cyanide-resistant respiration increases after irradiation of isolated mitochondria in the presence of Photofrin. This suggests an enhancement of electron leakage which has been evaluated by measuring superoxide radical formation in submitochondrial particles incubated with 6 micrograms/ml Photofrin in the medium and irradiated with increasing doses of light at 365 nm. After a dose of 4.5 kJ/m2 has been delivered, superoxide generation increases by a factor of approximately 2.5 at the level of NADH dehydrogenase and by a factor approximately 1.5 in the cyt bc1 region. These effects have been compared with changes observed in NADH-, succinate- and ascorbate-driven respiration and their implications discussed.
Salet
C
C
Laboratoire de Biophysique, INSERM U 201, Muséum National d'Histoire Naturelle, Paris, France.
Moreno
G
G
Ricchelli
F
F
D000818:Animals; D003486:Cyanides / Q000494:pharmacology; D014450:Electron Transport Complex III / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D003576:Electron Transport Complex IV / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D006415:Hematoporphyrins / Q000494:pharmacology*; D008297:Male; D008930:Mitochondria, Liver / Q000187:drug effects* / Q000378:metabolism* / Q000528:radiation effects; D009245:NADH Dehydrogenase / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D010101:Oxygen Consumption / Q000187:drug effects*; D010777:Photochemistry; D051381:Rats; D017208:Rats, Wistar; D013481:Superoxides / Q000378:metabolism*
D003486:Cyanides; D006415:Hematoporphyrins; D013481:Superoxides; D009245:NADH Dehydrogenase; D003576:Electron Transport Complex IV; D014450:Electron Transport Complex III