Fig. 3

Papillary muscle contraction in rat ventricular strips A Representative contraction curves recorded from papillary muscles B The net contraction that was recorded in electrically stimulated papillary muscle strips. (n = 4 each C Trace shows the preparation steps before SOCE measurement. The cells were first exposed to a Ca²⁺-free bath solution, containing various inhibitors (2 µM Thapsigargin (SERCA blocker), 10 µM verapamil (Ca²⁺ channel blocker), 10 mM TEA (K⁺ channel blocker), and 10 µM KB-R 7943 (Na⁺/Ca²⁺-exchanger blocker), and then caffeine (10 mM, 3 min intervals) was administered to empty SR/ER Ca²⁺ stores. At the end of 10 min, the fluorescence increase was calculated by switching to a bath solution containing Ca²⁺(1,8 mM) D Representative SOCE in rat left ventricular myocytes for control and MetS groups. E SOCE in rat left ventricular myocytes after SR Ca²⁺ depletion for the control, MetS, and MetS + BTP2 groups. Fluo3 AM dye was used for SOCE measurement. (n = 8,9,6 cells for CON, MetS, MetS + BTP2 respectively) (*: p < 0.05 vs. Con)