Figure 2

Cannabinoid receptor CB ₂ is expressed by cultured microglial cells. A, RT-PCR analysis of murine primary cultured microglial cells. A 239-bp band corresponding to CB₂ was specifically generated with primers described in the Materials and methods section. B, Graphical representation of RT-PCR band density ratio of CB₂ expression normalized to β-actin (mean +/- SD) is shown (n = 3 for each condition). ANOVA revealed significant between-group differences (control versus IFN-γ (50 U/mL) and IFN-γ (50 U/mL) versus IFN-γ (100 U/mL); p < 0.005). C, Western immunoblot analysis of murine primary cultured microglial cells using specific antibodies targeting CB₂ and β-actin proteins. D, Western blot band density is represented as ratio of CB₂ to β-actin (mean +/- SD; n = 4 for each condition). ANOVA revealed significant between-group differences [Control versus IFN-γ (50 U/mL) and IFN-γ (50 U/mL) versus IFN-γ (100 U/mL); ** p < 0.005]. E, Cannabinoid receptor CB₂ is expressed in microglial cells in situ. In white matter, microglial cells are positive in their somata and processes for CB₂. White arrowheads show positive cells as indicated. The expression of CB₂ (FITC; green) was co-localized with Iba-1, microglial cell marker (TRITC; red) as indicated. Bottom panel denotes merge signals. Bar denotes 10 μm.