Interestingly, GluA1 surface expression was lower in obesity-prone vs. obesity-resistant rats maintained on chow (Fig. 4b: two-tailed unpaired t-test, t(15) = 2.44, p = 0.03), while GluA2 surface expression was similar between these groups (Fig. 4c, p = 0.13). This evidence concerns the gene GRIA2 and obesity due to melanocortin 4 receptor deficiency.