Kd: 1 nM (Ca ²⁺ -activated K ⁺ channel)

Iberiotoxin reversibly blocks Ca2+-activated K+ channel in excised membrane patches from bovine aortic smooth muscle. Iberiotoxin acts exclusively at the outer face of the channel and functions with IC ₅₀ values of about 250 pM. Iberiotoxin is a partial inhibitor of ¹²⁵ I-charybdotoxin binding in bovine aortic sarcolemmal membrane vesicles (Ki of 2 ₅₀ pM). Iberiotoxin functions as a noncompetitive inhibitor of charybdotoxin binding.
Iberiotoxin treatment affects rat mesenchymal stem cells (rMSCs) migration in the absence of platelet lysate (PL) by inducing a decrease in cell migration suggesting that BK channels regulate rMSCs migration in basal conditions. 10 nM of Iberiotoxin abolishes the PL-induced migration effect on MSCs.

Male Wistar rats (6-7 weeks old) with chronic heart failure (CHF), Iberiotoxin (0.125 nmol/nl, 1.25 nmol/nl and 12.5 nmol/nl) is infused into paraventricular hypothalamic nucleus (PVN) by osmotic minipumps. After perfusion of Iberiotoxin by microinjection of rAAV2-KCNMB4 shRNA virus, right ventricular weight/body weight and lung weight/body weight ratio as well as left ventricular end-diastolic diameter are increased and left ventricular ejection fraction is decreased.