KCa2 (smallconductance Ca2+-activated potassium) channel negative allosteric modulator (IC50 = 1.1 μM). Increases the EC50 of Ca2+ on KCa2.3 channels by ~3-fold. Prolongs atrial effective refractory period (AERP) in rats. Reduces atrial fibrillation (AF) duration and prolongs atrial refractoriness without affecting ventricular refractory period in an animal AF model. Diness et al (2017) Termination of vernakalant-resistant atrial fibrillation by inhibition of small-conductance Ca2+-activated K+ channels in pigs. Circ.Arrhythm.Electrophysiol. 10 e005125 PMID:29018164 |Simó-Vicens et al (2017) A new negative allosteric modulator, AP14145, for the study of smallconductance calcium-activated potassium (KCa2) channels. Br.J.Pharmacol. 174 4396 PMID:28925012
5(6)-DiHET is a racemic compound synthesized through the action of epoxide hydrolases on 5(6)-EET, encompassing both enantiomeric forms. It serves as a quantitative marker for 5(6)-EET, facilitating its measurement by utilizing the compound's conversion to 5(6)-δ-lactone in solution. Additionally, 5(6)-DiHET activates large-conductance calcium-activated potassium (KCa1.1 BK) channels in rat small coronary artery smooth muscle cells, supporting its biological significance in vascular regulation. It also acts as a substrate for sheep seminal vesicle COX, leading to the in vitro production of 5,6-dihydroxy prostaglandin E1 and F1α metabolites. Notably, its levels diminish in the plasma of rats subjected to a high-fat diet, indicating a potential role in the pathophysiology of hyperlipidemia.
Apamin TFA (Apamine TFA) is a toxin found in bee venom. It is a potent blocker of smallconductance Ca2+-activated K+ (SK, KCa2) channels that is more effective at SK2 than SK1 and SK3.
Chlorotoxin is a 36-amino acid peptide found in the venom of the deathstalker scorpion (Leiurus quinquestriatus) which blocks small-conductance chloride channels.