Figure 3.

Overexpression of GRK6 in ARC region reversed chronic visceral pain in NMD rats. (a) A standard diagram (left) indicates the coronal section at 3.0 mm posterior to Bregma. A fluorescence image of GRK6 (middle, green) was recorded from the ARC area indicated within the red square on the diagram (left). Scale bar = 100 µm. The image (right) was a needle track from cerebral cortex to ARC region dyed by nitrite staining. Scale bar = 1200 µm. (b) Many LV-GFP-positive cells (top middle, green) were associated with NeuN-positive cells (top left, red). Almost all the LV-GFP-positive cells (bottom middle, green) were co-expressed with GRK6-positive cells (bottom left, red). Scale bar = 50 µm. (c) GRK6 protein expression in ARC of LV-GRK6 rats was significantly upregulated when compared with LV-NC rats (n = 4 for each group, *p < 0.05, two sample t-test). (d) Overexpression of GRK6 in ARC significantly attenuated chronic visceral pain sensitivity of adult NMD rats (LV-NC group n = 7 and LV-GRK6 group n = 10, **p < 0.01, ***p < 0.001, vs. LV-NC, two-way ANOVA). Compared with LV-NC rats, the mechanical (e) and thermal (f) pain thresholds of hindpaw of LV-GRK6 rats had no significant change (n = 8 rats for each group, p>0.05, Mann–Whitney test). GRK6: G protein-coupled kinase 6; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; NC: negative control; LV: lentiviral.