ML 133 is a selective inhibitor of inwardly rectifying Kir2.x potassium channels. ML 133 exhibits no effect on rKir1.1.
Biochem/physiol Actions
ML133 hydrochloride is a selective inhibitor of the Kir2 family of inward rectifier (IRK, KCNJ) potassium channels. ML133 inhibits Kir2.1 with IC50 of 1.8 μM at pH 7.4 and 290 nM at pH8.5. It exhibits little selectivity against other members of Kir2.x family channels, but has no effect on Kir1.1 (IC50 > 300 μM), and displays weak activity for Kir4.1 (76 μM) and Kir7.1 (33 μM), making ML133 the most selective small molecule inhibitor of the Kir family reported to date. It also showed modest selectivity versus hERG and a larger panel of GPCRs, ion channels and transporters.
