Electroacupuncture to ST36 ameliorates behavioral and biochemical responses to restraint stress in rats

Acupuncture has been used for the treatment and prevention of stress-related disorders. In the present study, the effect of electroacupuncture on the behavioral and biochemical responses to restraint stress was evaluated in rats.Sprague-Dawley male rats underwent immobilization stress for 21 days (6 hours/day). Electroacupuncture (2 Hz, 2 mA and 10 minutes) was applied either to the acupuncture point ST36 (Joksamni) or the non-acupuncture point in the tail for the last 7 days. Rats were randomly divided into four groups: the normal group (n=10, without the restraint stress), the stress group (n=10, with restraint stress), the ST36 group (n=10, with restraint stress and electroacupuncture to ST36) and the non-acupuncture group (n=10, with restraint stress and electroacupuncture to the non-acupuncture point). The anxiety-related behavior was tested using the elevated plus maze and the Vogel test on day 22. The serum concentration of corticosterone was determined using an enzyme-linked immunosorbent assay kit. The expression of tyrosine hydroxylase in the locus coeruleus was measured by immunohistochemistry.Restraint stress increased the response of the anxiety-related behavior. The serum level of corticosterone and the number of tyrosine hydroxylase-immunoreactive cells were also increased. The ST36 group showed a significant decrease of anxiety-related behavioral response, compared with the stress group. The serum corticosterone level and tyrosine hydroxylase-immunoreactive expression were also decreased in the ST36 group.These findings suggest that electroacupuncture to ST36 might play a role in reducing the stress-related responses, which may be helpful for the treatment of stress-related disorders.