Objective: To observe the effect of Shugan Hewei decoction (SHD) on the expression of calcitonin gene related protein (CGRP) of medulla oblongata

spinal cord and gastric mucosa in depression model rats. Method: Totally 100 SPF Wistar rats (half male and female) were randomized into the normal group

model group

fluoxetine 0.36 mg·kg-1 group and the high and low dosage groups of SHD

with 20 in each group. The depression model was established with chronic unpredictable mild stress (CUMS) and separation for 4 weeks. The 3rd week after modeling each treatment group was given corresponding medicines. Fluoxetine group and high

low dosage(20

10 g·kg-1) of SHD group and were given for fourteen days. At the end of the fourth week

the internal fixation method was used to collect medulla oblongata vagus nerve nucleus tissue

spinal cord tissue (T6-T8) and gastric mucosa tissue. The method of immunohistochemistry (IHC) was used to detect the expression of CGRP in the above organizations. Result: Comparing with the normal group

the content of CGRP increased significantly in medulla oblongata

spinal cord and gastric mucosa of model rats(P<0.01). Compared with the model group

the content of CGRP reduced significantly in medulla oblongata

spinal cord and gastric mucosa of high

low dosage of SHD group and fluoxetine group(P<0.05

P<0.01).In addition

the effect of high dosage of SHD was equal to fluoxetine group in medulla oblongata and spinal cord

while the former was better than the later in gastric mucosa(P<0.05). Conclusion: SHD has regulation effects on the expression of CGRP in the signal path of brain-gut axis ‘medulla oblongata-spinal cord-gastric mucosa’

which may be part of the mechanism for relieving depression and improving gastrointestinal function.