Objective To investigate the effects of electroacupuncture(EA)on the expression of corticotropin releasing hormone(CRH)and CRHR1mRNA in paraventricular nucleus(PVN)of hypothalamus

to explore its mechanism in anti-anxiety.Methods Thirty-three male SD rats were randomly divided into control

model and EA groups.Chronic emotional stress anxiety model was established by using chronic unpredictable emotional stress stimulation for 21 days.EA(15/25 Hz

1-2 mA)was applied to "Baihui"(GV 20)and "Sanyinjiao"(SP 6)for 15 min/d and 21 days.The expression of CRH and CRHR1mRNA in hypothalamic PVN was measured by immunohistochemistry and in situ hybridization techniques separately.Results Compared with control group

the values of open-arms entries(OE%)and open-arms time(OT%)in model group were decreased significantly(P<0.01).In comparison with model group

OE% and OT% in EA group were increased obviously(P<0.05

P<0.01).Compared with control group

the optical density values of CRH immuno-reaction positive products and CRHR1mRNA expressed neurons of hypothalamic PVN in model group were increased obviously(P<0.05

P<0.01);while in comparison with model group

those of CRH and CRHR1mRNA in EA group were significantly decreased(P<0.05

P<0.01).Conclusion EA can effectively relieve chronic stress stimulation induced anxiety in the rat

which is closely related to its effect in down regulating both CRH and CRHR1mRNA expression in PVN of hypothalamus.