Figure 5.
Blockade of SKCa/IKCa inhibits hyperpolarization in response to FCCP in endothelium of old mice. (A) Representative continuous Vm recording during 3 × 10–7 M FCCP in the absence and presence of SKCa/IKCa blockade (3 × 10–7 M apamin + 10–7 M charybdotoxin; Ap + ChTx). (B) Summary data illustrating that SKCa/IKCa blockade reverses hyperpolarization to depolarization during mitochondrial uncoupling with FCCP. Compared to control Vm, FCCP evoked hyperpolarization (ΔVm ≈ −15 mV). Treatment with Ap + ChTx alone produced ≈10 mV depolarization; in the presence of FCCP, Ap + ChTx depolarized cells by ≈ 25 mV vs. control. *p < .05 (n = 4). FCCP = carbonyl cyanide-4-(trifluoromethoxy)phenylhydrazone; SKCa/IKCa, small- and intermediate K+ channel.