Mitochondria play a central role in the regulation of cell function. Ca2+ entry into mitochondria represents a central event in the regulation of ATP production, intracellular Ca2+ homesotasis and mitochondrial permeability transition pore opening. Until recently, our understanding of the mechanisms of mitochondria Ca2+ uptake was largely limited by the use of indirect optical methods. Utilization of patch-clamp method to isolated mitoplasts allowed characterizing single channel properties of Ca2+ permeable channels in the inner mitochon- Дослідження кальцієвих каналів мітохондріальної мембрани ендотеліальних клітин ISSN 0201-8489 Фізіол. журн., 2014, Т. 60, № 1 69 drial membrane. Here we show the presence of three types of single channel activities of Ca2+ permeable channels in mitoplasts isolated from endothelial cells. While the identity and molecular structure of these channels still remain to be identified, these findings point for complex mechanisms of Ca2+ entry in mitochondria.