It is worth noting that pharmacological silencing of mGluR5 using CTEP in amyotrophic lateral sclerosis (ALS) and AD mice, two neurodegenerative diseases in which glutamate-mediated excitotoxicity plays a crucial role, reduced the number of activated microglia (Abd-Elrahman et al., 2020b; Milanese et al., 2021). This evidence concerns the gene GRM5 and Alzheimer disease.