( A ), ( C ): An example of RT-PCR results for the levels of mRNA of NMDA receptor NR1 ( A ) and NR2B ( C ) subunits and GAPDH. (B), (D): The quantitative RT-PCR results for the levels of mRNA of NMDA receptor NR1 (B) and NR2B (D) subunit of the offspring rats (P14) in different groups. In (A), each white letter at the bottom of the lane represents the result from certain group (a: Control, b: M, c: M + DM, d: DM). The values of NR1 and NR2B subunits in the control group were arbitrarily set at 100%. Data are presented as mean ± SEM. One-way ANOVA followed by the Newman-Keuls test was used to analyze the data. (B: **p<0.01 for the morphine group vs the control group; D: **p < 0.01, for the morphine group vs the control group, n = 3).