By analyzing experiments involving a wide range of competitive and noncompetitive agonists and antagonists of group I mGluRs in various models of cerebral ischemia, Pellegrini-Giampietro concluded that mGluR1 and mGluR5 play distinct roles in ischemia-induced neuronal death, with mGluR1 primarily involved in the mechanisms leading to post-ischemic neuronal injury [25]. This evidence concerns the gene GRM5 and brain ischemia.