The effect of antimycin A on mouse liver inner mitochondrial membrane channel activity

In a patch-clamp study, we found antimycin A in low (1-2) μM concentrations decreased the open probability of the multiple conductance channel activity and the ∼110 picosiemens channel of the inner mitochondrial membrane (for a review of mitochondrial channels see Kinnally, K. W., Antonenko, Yu. N., and Zorov, D. B. (1992) J. Bioenerg. Biomembr. 24, 99-110). Higher antimycin A concentrations (e.g. 10 μM) facilitated multiple conductance channel opening. These effects were reversible, and the binding site(s) are probably distinct from those responsible for the inhibition of the electron transport chain, since the latter are virtually irreversible. A model with two closed and two open states is presented for the ∼110-picosiemens activity.