GRM5 and ischemia: It is intriguing that both antagonist MPEP and agonist CHPG [(RS)-2-chloro-5-hydroxyphenylglycine] of mGluR5 have neuroprotective effects in rat MCAo model (Bao et al., 2001), whereas CHPG has no effect on brain injury in the endothelian-1-induced focal ischaemia model (Riek-Burchardt et al., 2007).