Аннотация:The permeability transition pore in mitochondria (MPTP) and the ATP-binding cassettetransporters (ABC transporters) in cell membranes provide the efflux of low-molecular compoundsacross mitochondrial and cell membranes, respectively. The inhibition of ABC transporters, especially of those related to multi drug resistance (MDR) proteins, is an actively explored approach to enhance intracellular drug accumulation and increase thereby the efficiency of anticancer therapy. Although there is evidence showing the simultaneous effect of some inhibitors on both MDR-related proteins and mitochondrial functions, their influence on MPTP has not been previously studied. We examined the participation of verapamil and quinidine, classified now as the first generation of MDR modulators, and avermectin, which has recently been actively studied as an MDR inhibitor, in the regulationof the MPTP opening.