Figure 5. D2DR antagonist sulpiride suppresses morphine exposure induced activation of astrocytes and microglia in the spinal cord and decreases pro-inflammatory cytokines TNF-α and IL-1β.

(A,B) Confocal images and immunofluorescence showed that chronic morphine treatment activated the astrocytes and microglia in the spinal dorsal horn. Sulpiride (8 μg/10 μl, i.t.) inhibited the activation of the glias in the spinal cord (10X and 20X magnification). Quantification of GFAP and IBA1 immunofluorescence were represented as mean fluorescence pixels in the superficial dorsal horns. (C,D) Western blot showed that sulpiride (1, 4 and 8 μg/10 μl, i.t.) decreased the up-regulated expression of GFAP and IBA1. (E,F) Western blot analysis data showed that the up-regulated expression of the pro-inflammatory cytokines TNF-α and IL-1β were decreased by sulpiride (1, 4 and 8 μg/10 μl, i.t.) (n = 3, *P < 0.05, **P < 0.01, compared with morphine group). Representative western blot bands and a data summary are shown. All spinal cords were collected on day 7, 30 min after chronic morphine exposure (n = 4, *P < 0.05, **P < 0.01, compared with morphine group).