Figure 4.

Mechanism of contraction induced by KCNQ channel blockers. Original records show contractile responses of rat intrapulmonary artery to 50 mM KCl, followed by 10 μM linopirdine (A, C, E) or 1 μM XE991 (B, D, F) under control conditions and in the presence of Ca²⁺-free (0Ca) bathing solution (A, B), 1 μM nifedipine (C, D) or 10 μM levcromakalim (E, F).