GRIN2A and spinocerebellar ataxia type 1: No changes in protein levels of mGlu5 receptors, Homer-1, GluN1 and GluN2A subunits of NMDA receptors, and phosphorylated GluA2 subunit of AMPA receptors were found in the hippocampus of 8-week-old SCA1 mice (Figure 2B,D–F).