Figure 1.

Pharmacology of the large-conductance calcium-regulated potassium channel (mitoBK_Ca ) from the mitochondria of human endothelial cells. (a) Schematic representation of mitochondria and mitoplast preparation from human endothelial cells, including mitoplast patching and the patch-clamp experiment in inside-out mode with the perfusion system. The matrix side of the mitochondrial membrane is exposed to externally added substances from the perfusion system. (b) Regulation of the mitoBK_Ca by calcium ions. Representative single-channel current-time recordings recorded at different “matrix” Ca²⁺ concentrations (1, 10, 30 and 100 μM) and applied voltages (−40 and +40 mV) (n = 6) are shown. “-“ indicates a closed state of the channel. (c) The effect of mitoBK_Ca modulators, NS11021 (1 µM) and paxilline (Pax; 1 µM), on the single-channel activity at −40 mV. “-“ indicates a closed state of the channel. (d) The influence of NS11021 (n = 5) and paxilline (n = 4) on the probability of opening of the mitoBK_Ca channel. (e) Dependence of the probability of opening of the mitoBK_Ca channel on Ca²⁺ concentration (n = 6). *** p < 0.001, **p < 0.01. All data are presented as the means ± SD.