The capsaicin was applied into the Mass after PD98059 i.t. administration in the rats with M1 CFA on day 3 or week 6. A and B: Neurolucida drawings (A) and Rostral-caudal distribution (B) of pERK-IR and Fos-IR cells in the Vi/Vc and Vc. C: * indicates significant decrease in the number of pERK-IR or Fos-IR cells. Each region in each model was compared with M1 CFA/Mass cap rats with saline i.t. on day 3 or week 6, respectively.