Figure 4. A. The I-T (current-time relationship) curves were constructed from the negative slope region of a ramp voltage clamp, and were sequentially shown during no drug (control, trace c), H₂O₂ alone (trace a), H₂O₂ plus 20 µM resveratrol (trace b), and Ni²⁺ (5 mM) (trace d) in the continued presence of 300 µM H₂O₂.

B. Ni²⁺-sensitive I _NCX was obtained by subtracting the data in the trace d from the data in trace a, b, and c in panel A. The enhanced reverse I _NCX induced by H₂O₂ was restored by 20 µM resveratrol. C. Histograms show the mean current densities of I _NCX obtained from B. Values are expressed as mean ± SD, n = 8 cells/group. ^#P<0.01 versus control group; ^*P<0.01 versus H₂O₂ group. D. Similar to A, the I-T (current-time relationship) curves were constructed, and were shown during no drug (control, trace g), H₂O₂ alone (trace e), H₂O₂ plus 4 µM RAN (trace f), and Ni²⁺ (5 mM) (trace h) in the continued presence of H₂O₂. E. Ni²⁺-sensitive I _NCX were obtained by subtracting the data in trace h from the data in traces e, f and g in panel D. The reverse I _NCX increased by H₂O₂ was restored by 4 µM RAN. F. Histograms show the mean current densities of I _NCX obtained from E. Values are expressed as mean ± SD, n = 8 cells/group. ^#P<0.01 versus control group; ^*P<0.01 versus H₂O₂ group. G. Similar to A and D, the I-T (current-time relationship) curves were constructed, and were shown during no drug (control, trace k), H₂O₂ alone (trace i), H₂O₂ plus 4 µM TTX (trace j), and Ni²⁺ (5 mM) (trace l) in the continued presence of H₂O₂. H. Ni²⁺-sensitive I _NCX were obtained by subtracting the data in trace l from the data in traces i, j and k in panel G. The reverse I _NCX increased by H₂O₂ was restored by 4 µM TTX. I. Histograms show the mean current densities of I _NCX obtained from H. Values are expressed as mean ± SD, n = 8 cells/group. ^#P<0.01 versus control group; ^*P<0.01 versus H₂O₂ group.