Figure 4.

The effect of chronic administration of morphine (MRF), magnesium and morphine cotreatment (Mg²⁺ + MRF), and magnesium (Mg²⁺) in periaqueductal gray matter (PAG) lysate from streptozotocin (STZ)-treated rats on the expression of N-methyl-D-aspartate receptor (NMDAR) NR1 subunit phosphorylation. (A) Representative results of the Western blot assay showing phosphorylated serine 896 (pSer896) NR1 (top panel) and total NR1 (bottom panel). (B) The level of Ser896 phosphorylation expressed as the ratio of the phosphorylated form to the total form of the tested proteins (pNR1/NR1). (C) Changes in the expression of total NR1. Statistical analysis was performed using one-way ANOVA followed by Dunnett’s post-hoc test. * p < 0.05 vs. STZ (graph B). There were no statistically significant differences in total NR1 (p > 0.05; graph C); n = 6 rats/group.