Figure 3.

Cytokine gene expression in the rat brain in response to lipopolysaccharides (LPS), with and without morphine tolerance. Gene expression of interleukins Interleukin (Il)-1β, Il-6, Il-12a, Il-12b, Il-18, and Il-33 in the brains of rats, with and without morphine tolerance, following an i.p. injection of either 250 µg/kg LPS or saline (n = 3–5 rats per group) was determined using a Polymerase Chain Reaction (PCR) array. Data were calculated using the ΔΔCT method relative to the control group (placebo-control + saline) and are represented as a fold change. * p < 0.05, ** p < 0.01, *** p < 0.001