The mitochondrial K-ATP channel opener diazoxide upregulates STIM1 and Orai1 via ROS and the MAPK pathway in adult rat cardiomyocytes

摘要

Dzx increases STIM1 and Orai1 expression. a A representative STIM1 western blot of whole membrane fractions from control and Dzx-treated hearts with actin as a loading control. b Means (± SEM, n = 7) of normalized densities of STIM1 bands. Open circles represent individual determinations. c Confocal microscopy images of cardiomyocytes under control conditions and after Dzx-treatment. Images show localization of STIM1 (red) with DAPI-labeled nuclei (blue). Calibration bar, 10 μm. d Mean fluorescence intensity along the longitudinal axis of the cardiomyocytes shown in c, the dotted lines indicate averages of all values. e–g Particle analysis of STIM1 in cardiomyocytes under the same conditions as in c. Mean numbers of particles (e), mean particle size (f), and ratios of total particle area and cell area (g) (± SEM, n = 5–10). Empty bars, control; filled bars, Dzx. h Representative Orai1 western blot of whole membrane fractions from control and Dzx-treated hearts, with an actin loading control. i Mean normalized densities of Orai1 bands (± SEM, n = 4). Open circles represent individual determinations. j Representative immunofluorescence images of cardiomyocytes showing distributions of Orai1 under the indicated experimental conditions. k Mean (± SEM, n = 6–10) number of particles of Orai1 from confocal images of cardiomyocytes under experimental conditions as in j. *p  < 0.05, **p < 0.01