Fig. 2

Identification and characterization of sensitized neurons in the CeA after chronification of mechanical hyperalgesia. A Representative low (left) and high magnification (right) images of colocalized pERK- and PKC-δ- positive neurons in the CeA. B After chronic NTG injection, the numbers of pERK positive neurons in the CeA were significantly higher than those in the control group (n = 6 per group; p = 0.046). Scale bar: 100 μm. C Rostro-caudal distribution of the percentage of pERK positive neurons colocalized with PKC-δ positive neurons in the CeA (left, n = 6 per group; p = 0.029); the percentage of pERK/PKC-δ positive neurons of the entire CeA was significantly higher in the chronic NTG treatment group than that in the control group (right, n = 6 per group; p = 0.0003). D Rostro-caudal distribution of the percentage of PKC-δ positive neurons colocalized with pERK positive neurons in the CeA (left, n = 6 per group); the percentage of PKC-δ/pERK positive neurons of the entire CeA was significantly higher in the chronic NTG treatment group than that in the control group (right, n = 6 per group; p = 0.001). E Representative low (left) and high magnification (right) images of colocalized pERK- and SOM- positive neurons in the CeA. Scale bar: 100 μm. F Schematic illustration of the rostro-caudal anatomical location of CeA relative to the position of bregma. G Rostro-caudal distribution of the percentage of pERK positive neurons colocalized with SOM positive neurons in the CeA (left, n = 5 per group). The percentage of pERK/SOM positive neurons in the entire CeA was not different between the NTG treatment and control groups (right, n = 5 per group; p = 0.597). H Rostro-caudal distribution of the percentage of SOM positive neurons colocalized with pERK positive neurons in the CeA (left, n = 5 per group). The percentage of the SOM/pERK positive neurons in the entire CeA was not different between the NTG treatment and control groups (right, n = 5 per group; p = 0.711). All data shown are mean ± SEM and analyzed Mann-Whitney U test. Significance levels set at p < 0.05 *, p < 0.01 **, and p < 0.001 ***