Iberiotoxin is a toxin isolated from Buthus tamulus scorpion venom. Iberiotoxin is a selective high conductance high conductance Ca²⁺-activated K⁺ channel inhibitor with a K_d of ~1 nM. Iberiotoxin does not block other types of voltage-dependent ion channels^[1][2][3].

Kd: 1 nM (Ca²⁺-activated K⁺ channel)^[1][3]

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 IC₅₀ values of about 250 pM. Iberiotoxin is a partial inhibitor of ¹²⁵I-charybdotoxin binding in bovine aortic sarcolemmal membrane vesicles (Ki of 2₅₀ pM). Iberiotoxin functions as a noncompetitive inhibitor of charybdotoxin binding^[1].
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^[2].

MCE has not independently confirmed the accuracy of these methods. They are for reference only.

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^[4].

MCE has not independently confirmed the accuracy of these methods. They are for reference only.

4230.85

C₁₇₉H₂₇₄N₅₀O₅₅S₇

129203-60-7

Glp-Phe-Thr-Asp-Val-Asp-Cys-Ser-Val-Ser-Lys-Glu-Cys-Trp-Ser-Val-Cys-Lys-Asp-Leu-Phe-Gly-Val-Asp-Arg-Gly-Lys-Cys-Met-Gly-Lys-Lys-Cys-Arg-Cys-Tyr-Gln (Disulfide bridge:Cys7-Cys28,Cys13-Cys33,Cys17-Cys35)

{Glp}-FTDVDCSVSKECWSVCKDLFGVDRGKCMGKKCRCYQ (Disulfide bridge:Cys7-Cys28,Cys13-Cys33,Cys17-Cys35)

Room temperature in continental US; may vary elsewhere.

• [1]. A Galvez, et al. Purification and Characterization of a Unique, Potent, Peptidyl Probe for the High Conductance Calcium-Activated Potassium Channel From Venom of the Scorpion Buthus Tamulus. J Biol Chem. 1990 Jul 5;265(19):11083-90.

  [2]. Santiago Echeverry, et al. Activation of BK Channel Contributes to PL-Induced Mesenchymal Stem Cell Migration. Front Physiol. 2020 Mar 24;11:210.

  [3]. S Candia, et al. Mode of Action of Iberiotoxin, a Potent Blocker of the Large Conductance Ca(2+)-activated K+ Channel. Biophys J. 1992 Aug;63(2):583-90.

  [4]. R J Wang, et al. Downregulation of Large Conductance Calcium-Activated Potassium Channels in Paraventricular Nucleus Contributes to Sympathoexcitation in Rats With Chronic Heart Failure. Zhonghua Xin Xue Guan Bing Za Zhi. 2018 Mar 24;46(3):178-186.