GRM5 and Alzheimer disease: Furthermore, PrPC-mGluR5 coupling is involved in Aβ-mediated inhibition of LTP and Aβ-facilitated LTD in vivo [22], and genetic ablation of mGluR5 reverses disease-related memory deficits in a murine model of AD (APPswe/PS1ΔE9) [23].