Figure 3.

Effect of opioid and CB receptor ligands on LPS-induced production of proinflammatory cytokine and nitrite in primary microglial cells. Microglial cells were treated with either LPS alone, LPS + morphine (MOR; 100 nM), LPS + JWH-015 a CB₂ receptor agonist (JWH; 100 nM)), LPS + DAMGO (100 nM), LPS + AM 251 a selective CB₁ receptor antagonist (100 nM) or LPS + AM 630 a selective CB₂ receptor antagonist (100 nM) for 24 h. The antagonists were added 30 min before morphine. Data shown are mean ± SE values of four separate experiments performed in triplicate (n= 4). *P < 0.01 significantly different from control conditions (absence of drugs, CTR); ^#P < 0.01 significantly different from LPS conditions (0); ^§P < 0.01 significantly different from LPS + MOR; ^†P < 0.01 significantly different from LPS + MOR + JWH; analysis was by anova followed by Dunnett's test.