GRM5 and Alzheimer disease: The present study indicates that prolonged ictal-like discharges in the hippocampal CA3 neuronal network of 3-week-old 3xTg-AD mice were suppressed by mGluR5 blockade with MPEP, showing that synaptic activation of group I mGluRs was sufficient to sustain this ictal-like activity in the transgenic mice.