Figure 4.

Activation of TRPC3 channels protects IK_Ca and SK_Ca channels from H-R-induced inhibition in PCAECs. (a) Representative traces and current-voltage relationship of whole-cell K⁺ current in PCAECs from different treatment groups before and after bradykinin (BK) stimulation with further application of the IK_Ca channel blocker TRAM-34 and the SK_Ca channel blocker apamin. Under H-R condition, PCAECs treated with OAG shows enhanced basal and BK-induced K⁺ currents compared with the cells without OAG-treatment and such enhancement is diminished by Pyr3. *p < 0.05, **p < 0.01, BK vs. basal; ^#p < 0.05, ^##p < 0.01, BK + TRAM-34 vs. BK; ^{^}p < 0.05, ^{^^}p < 0.01, BK + TRAM-34 + Apamin vs. BK + TRAM-34. (b) Summarized data of BK-induced IK_Ca and SK_Ca currents from 5 independent experiments, each obtained from cell isolates of different hearts. PCAECs were subjected to H-R exposure in the absence or presence of the TRPC3/6/7 activator OAG before patch-clamp recording. For cells subjected to H-R exposure and OAG treatment, the current recording was performed under the condition without (H-R + OAG-treated) or with Pyr3 application (H-R + OAG-treated + Pyr3). *p < 0.05, **p < 0.01; one-way ANOVA and Scheffe post-hoc test.