P2RX4 and major depressive disorder: Purinergic Receptor Transcripts: In the all subject analysis, P2RY12 mRNA expression was significantly lower in the MDD-NS compared to CTL subjects in the white matter, with a significant main effect of disease observed (two-way ANOVA: F(2,14) = 5.82, p = 0.01, Figure 2F and Figure 3), as well as deep gray matter (one-way ANOVA: F(2,22) = 3.69, p = 0.04, Figure S2).