Effects of rhodamine 123 in the dark and after irradiation on mitochondrial energy metabolism.
Isolated rat liver mitochondria have been used to study the mechanism of toxicity of Rhodamine 123 (Rho 123) in the dark and after irradiation with visible light. We report an inhibition of adenosine 5'-diphosphate phosphorylation which is increased after illumination. In the dark, the first steps of the phosphorylation process (i.e. the entry of substrates into the matrix, the electron transport to oxygen and the creation of the proton gradient) as well as ATPase activity are not significantly perturbed at Rho 123 concentration below 10 micrograms/mL. In contrast, the movements of the phosphate compounds are drastically impaired. Irradiation strengthens the detrimental effects in an oxygen dependent process. The nature of the noxious transient species is not clearly established, but it is suggested that singlet oxygen could be responsible for the observed damage.
Atlante
A
A
Centro di Studio sui Mitocondri e Metabolismo Energetico C.N.R., Bari, Italy.
Passarella
S
S
Moreno
G
G
Salet
C
C
D000244:Adenosine Diphosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D003624:Darkness; D004734:Energy Metabolism / Q000187:drug effects* / Q000528:radiation effects; D008027:Light; D008564:Membrane Potentials / Q000187:drug effects; D008930:Mitochondria, Liver / Q000187:drug effects* / Q000378:metabolism / Q000528:radiation effects; D010100:Oxygen / Q000378:metabolism; D010101:Oxygen Consumption / Q000187:drug effects* / Q000528:radiation effects; D010710:Phosphates / Q000378:metabolism; D010777:Photochemistry; D006180:Proton-Translocating ATPases / Q000378:metabolism; D011838:Radiation-Sensitizing Agents / Q000494:pharmacology*; D051381:Rats; D020112:Rhodamine 123; D012235:Rhodamines / Q000494:pharmacology*; D012402:Rotenone / Q000494:pharmacology; D026082:Singlet Oxygen
D010710:Phosphates; D011838:Radiation-Sensitizing Agents; D012235:Rhodamines; D012402:Rotenone; D026082:Singlet Oxygen; D020112:Rhodamine 123; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D006180:Proton-Translocating ATPases; D010100:Oxygen