Fig. 4. Representative western blots of N -methyl-d-aspartate receptor NR1 subunit after injection of NR1 small interfering RNA (siRNA). (A ) NR1-1 and NR1-2 siRNA significantly inhibited the expression of NR1 protein. Lane representing PEI: 3 days after intradermal injection of 2 μl polyethyleneimine (PEI) as the control. Lanes representing NR1-1, 1-2, 1-3: 3 days after intradermal injection of 1 nmol NR1-1, 1-2, or 1-3 siRNA. (B ) NR1-1 siRNA at doses of 1 nmol and 2 nmol significantly inhibited the expression of NR1 protein. Lanes representing saline, PEI, MM, 0.5 nmol, 1 nmol, 2 nmol: 3 days after intradermal injection of 100 μl saline, 2 μl PEI, 1 nmol mismatched NR1-1 siRNA, 0.5 nmol, 1 nmol, or 2 nmol NR1-1 siRNA. (C ) Significant inhibition of NR1 protein was noted 3 and 7 days after injection of 1 nmol NR1-1 siRNA. Lanes representing PEI or siRNA at 3, 7, 14, and 21 days: 3, 7, 14, and 21 days after intradermal injection of 2 μl of PEI as the control or 1 nmol NR1-1 siRNA. Six rats were used for every time point. *P < 0.05 vs . control groups (n = 6 each group). Values are mean ± SD.