GRIA1 and amyotrophic lateral sclerosis: However, a significant increase in α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor 1 (AMPAR GluR-1) ** p < 0.01 and a tendency to increase in the expression of gamma-aminobutyric acid receptor subunit beta-2 (GABAAB2) (# p < 0.1) was found in the frontal cortex in ALS when compared to controls (Figure 6).