Voltage- and use-dependent open-channel antagonist of AMPA receptors. Selective between subtypes; blocks GluR2 subunit-lacking receptors more potently than GluR2-containing receptors (KD for GluR2-containing AMPAR is 210 times higher at -80 mV). More potent than IEM 1460 (Cat. No. 1636) and IEM 1754 (Cat. No. 4199) due to a slower unblocking rate.