LY404187 is a benzothiadiazide positive allosteric modulator of AMPA receptors. It increases glutamate-induced activation of GluR1i, -2i, -2o, -3i, and -4i subunit-containing AMPA receptors with EC50 values of 5.65, 0.15, 1.44, 1.66, and 0.21 μM, respectively, in a calcium influx assay. LY404187 is selective for these AMPA receptors over GluR6 subunit-containing kainate receptors at 10 μM. LY404187 increases currents induced by glutamate and AMPA in rat prefrontal cortex pyramidal neurons (EC50s = 1.3 and 1.2 μM, respectively) but not in AMPA-stimulated primary rat embryonic hippocampal or primary cerebellar Purkinje neurons. LY404187 prevents decreases in the number of dopaminergic neurons in the substantia nigra induced by MPTP and 6-OHDA in mouse and rat, respectively, models of Parkinson’s disease when administered at a dose of 0.5 mg/kg per day.
