Table 2. Protein and mRNA expression of DOR and KOR in primary microglial cells.

Primary rat microglial cells were isolated as described in Methods, and 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 cells 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 28% and 25%, respectively; while numerical values for the percentage of control cells positive for intracellular DOR and KOR were 33% and 39%, respectively. *, **, and *** indicate statistically significant (p<0.05, p<0.01, and p<0.001, 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 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±7.99	100.00±11.60
	Tat 50nM	48.24±12.42 *	72.65±12.49
	Morphine 500nM	63.17±7.01 **	81.14±13.57
	Tat 50nM+Morphine 500nM	89.61±17.47	155.52±4.03 ##
intracellular expression [% of control]	Control	100.00±6.93	100.00±3.78
	Tat 50nM	43.63±4.49 ***	84.03±10.00
	Morphine 500nM	74.10±10.73 ***	124.25±2.32
	Tat 50nM+Morphine 500nM	107.65±2.32 #	170.00±3.32 #
mRNA [% of control]	Control	100.00±1.96	100.00±2.04
	Tat 50nM	137.84±7.07 *	109.64±2.91
	Morphine 500nM	96.73±3.80	98.93±10.96
	Tat 50nM+Morphine 500nM	109.77±7.17	121.41±10.09