Time course of treatment with norepinephrine 1 μM alone, LPS 10 ng/ml alone, or a combination of norepinephrine 1 μM plus LPS 10 ng/ml on the expression of COX-2 protein and mRNA (A-C). (A, B) Microglial cells were stimulated for 4, 8, and 24 hours. This was followed by western blot analysis against β-actin (42 kDa) and COX-2 (70 kDa). A representative western blot is shown here (A). Quantitative densitometric analysis of COX-2 normalized to β-actin loading control. *P < 0.05 with respect to LPS control. (C) Semi-quantitative analysis of the effect of the different treatment groups on COX-2 mRNA expression at different time points (15 min to 24 hours). [NE = norepinephrine].