1227301-51-0

IC50: 296 nM (GluR1), 296 nM (GluR1)

Ki: 0.29 μM (GluR5Q)

Philanthotoxin 74 in the micromolar concentration range displays selective inhibition between the two major subtypes of GluA2R-containing AMPARs, GluA1/A2R and GluA2R/A3, when these are coexpressed with γ-2 in oocytes. Philanthotoxin 74 is reported to fully inhibit GluA1/A2R receptors when applied at a concentration of 500 μM while producing 10% inhibition at GluA2R/A3 receptors. Philanthotoxin 74, when tested at concentrations of 100 and 500 μM, displays pronounced channel block (more than 80%) of GluA1/A2R but minimal block (less than 10%) of GluA2R/A3. Oocytes expressing GluA2R alone that homomeric GluA2R is virtually inert to philanthotoxin 74 in the 0.1-300 μM concentration range, displaying less than 5% inhibition at the maximum tested concentration of 300 μM. Philanthotoxin 74 inhibits these receptors nonselectively, with IC ₅₀ values of about 30 μM, in both the presence and absence of γ-2.