Abstract: Capsaicin can trigger certain types of pain responds by acting on C-fiber and peripheral axons in brain.The capsaicin (0.1mM) solution was injected into the cisterna magna of rats 1 h after the intragastric administration of vehicle,Gas or Gas-D (50 mg/kg,100 mg/kg).The animals were then kept in a reverse trendelenburg position (-30 degrees) for 30 min,followed by a prone position for 90 min.Then jugular vein blood of the rats was collected to detect the plasma nitro oxide (NO) and calcitonin gene related peptide (CGRP) levels;the rats were sacrificed and the whole brain were removed to determine the concentration of NO;TNC and TG were excised for immunohistochemical staining to observe the expression of CGRP,FBJ osteosarcoma oncogene protein (c-Fos) or PKR-like endoplasmic Reticulum Kinase (pERK);and they were validated by Western Blot.The results showed that Gas-D can significantly decrease the plasma NO and CGRP levels and inhibit the expression of pERK in TG and c-Fos/CGRP in TNC induced by capsaicin,and it showed a dose correlation.In conclusion,the efficacy of Gas-D on migraine is obviously effective,therefore it may be an alternate drug for the treatment of migraine.

Key words: capsaicin, CGRP, c-Fos, pERK, migraine