Figure 4.

E_M and I_K are similar in resistance PASMCs from wild-type and CGD mice (A) Resting E_M is similar in wild-type (filled bar) and CGD (empty bar) PASMCs. (B) Normoxic current density is similar in wild-type and CGD PASMCs. (C and D) In PASMCs from CGD mice, 4-AP, a Kv channel inhibitor, reduces I_K at negative potentials (−10 mV, C, ∗, P < 0.05). Tetraethylammonium (TEA) inhibits I_K only at positive potentials, where K_Ca channels are active (∗, P < 0.05, D). (E and F) Four minutes of acute hypoxia inhibits I_K (n = 4 cells/group, ∗, P < 0.01). (G and H) In separate experiments, 4 min of acute hypoxia inhibits I_K even after specifically inhibiting large conductance K_Ca channels with IBTX. This finding suggests the hypoxia-sensitive current is at least partially K_v current (†, ∗ P < 0.05 IBTX and hypoxia inhibit I_K, respectively).