FIGURE 4.

EESC via inhibiting ion channel-mediated Ca²⁺ influx inhibits high K⁺-induced contraction. (A) High K⁺ (80 mM) did not trigger contraction in a TR in Ca²⁺-free conditions (0 Ca²⁺ and 0.5 mM EGTA). After the addition of 2 mM Ca²⁺, contraction occurred, which was blocked by EESC. (B) After incubation with EESC, the 2 mM Ca²⁺-induced contraction scarcely occurred. Each of the experiments was performed in 8 TRs. These results indicate that EESC-induced relaxation is due to its inhibition of LVDCC-mediated Ca²⁺ influx.