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Effect of ruthenium red on calcium efflux from rat liver mitochondria
Author(s) -
Rigoni F.,
Mathien-Shire Y.,
Deana R.
Publication year - 1980
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(80)80310-3
Subject(s) - shire , chemistry , humanities , studio , art , philosophy , visual arts , linguistics
It is now apparent that Ca2+-uptake in mitochondria is driven by a membrane potential, negative inside, and that calcium is transported with two positive charges [l-8]. Evidence for a specific carrier is provided by the inhibitory effects on Ca2+-translocation of ruthenium red and lanthanides. The steady state distribution of calcium between mitochondria and the suspending medium most probably does not follow the Nernst equation, which suggests that separate pathways for Ca2+-uptake and release may exist. EPR experiments, in which Mn2+ was used as paramagnetic analogue of Ca2+, support this conclusion [9]. However, most evidence for a distinct pathway for Ca’+efflux has been obtained by experiments with ruthenium red. In fact this compound has been found to have different effects on Ca2+-transport: while it blocks the electrophoretic uptake completely it inhibits only slightly, or not at all, the Ca’+-efflux induced either by calcium chelators or by agents which collapse the membrane potential [9-181. Furthermore it can induce by itself a release of mitochondrial accumulated calcium. This release has been ascribed to a block of calcium cycling. It would be the consequence of a complete inhibition by ruthenium red of Ca2+-uptake,