Table 1. Protein and mRNA expression of DOR and KOR in N9 cells.

N9 microglial cell lines were treated for 24 h with 50nMTat, 500nM Morphine, or combined Tat/Morphine, after which the cells were either fixed and stained with antibodies to DOR or KOR using flow cytometry, or processed for real-time PCR analyses as described in Methods. All data were analyzed by ANOVA, and are presented as means ± SEM in relation to control cells. Numerical values for the percentage of control cells positive for cell surface DOR and KOR were 38% and 41%, respectively; while numerical values for the percentage of control cells positive for intracellular DOR and KOR were 68% and 80%, respectively. * and ** indicate statistically significant (p<0.05 and p<0.01, respectively) differences in opioid receptor expression in treated cells compared to control cells, while # and ## indicate statistically significant (p<0.05 and p<0.01, respectively) differences in cell surface opioid receptor expression in Tat/morphine treated cells as compared to cells treated with morphine alone.

	Treatment	DOR	KOR
Cell surface expression [% of control]	Control	100.00±13.13	100.00±9.99
	Tat 50nM	103.11±3.34	100.90±7.52
	Morphine 500nM	70.29±12.42 *	62.28±6.18 **
	Tat 50nM+Morphine 500nM	125.92±4.45 ##	100.54±15.26 #
intracellular expression [% of control]	Control	100.00±6.68	100.00±4.52
	Tat 50nM	97.50±4.86	101.92±2.65
	Morphine 500nM	124.13±5.80 *	99.95±10.87
	Tat 50nM+Morphine 500nM	117.00±6.02 *	90.16±7.94
mRNA [% of control]	Control	100.00±7.16	100.00±7.87
	Tat 50nM	151.35±21.77 *	92.48±7.33
	Morphine 500nM	117.49±22.03	110.05±9.75
	Tat 50nM+Morphine 500nM	78.28±15.77 *	64.79±10.42 **