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Reactive oxygen species production in synaptosomes is independent of ΔΨ m
Author(s) -
Sipos I.,
Tretter L.,
AdamVizi V.
Publication year - 2003
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.85.s2.19_2.x
Subject(s) - rotenone , antimycin a , oligomycin , respiratory chain , mitochondrion , reactive oxygen species , biophysics , chemistry , membrane potential , mitochondrial ros , mitochondrial respiratory chain , biochemistry , biology , enzyme , atpase
This study addressed whether dissipation of ΔΨ m had any influence on ROS generation of in situ neuronal mitochondria. The ROS formation was measured as a release of H 2 O 2 by Amplex Red assay. Complete blockage of Complex I by rotenone or Complex III by antimycin caused enhanced H 2 O 2 release. Dissipation of ΔΨ m by FCCP or DNP had no effect on the H 2 O 2 production induced by rotenone or antimycin. Antimycin substantially diminishes the ΔΨ m , but part of the membrane potential still maintained by the reverse function of mitochondrial ATP synthase. When antimycin was applied together with oligomycin, ΔΨ m was totally dissipated, but the ROS production decreased only by 15%. Rotenone inhibited the antimycin‐induced H 2 O 2 release by 55%, but not eliminated completely. These experiments suggest that in in situ mitochondria of synaptosomes (i) ROS generation because of inhibition of Complex I or III is not dependent on ΔΨ m and (ii) when Complex I is completely inhibited electrons entering the respiratory chain distal from rotenone site could fuel the ROS formation.