Objective: To probe into the mechanism of acupuncture for treatment of depression.
Methods: Thirty-two healthy SD male rats were randomly divided into a normal group, a model group, an electroacupuncture (EA) group and a Maprotiline group. The depression rat model was made in the latter three groups, and from the second day of the experiment EA was given at Baihui (GV 20), "Yintang" (EX-HN 1), "Zusanli" (ST 36) and "Fenglong" (ST 40) in the EA group, once every other day; the rats in the Maprotiline group were treated with oral administration of Maprotiline hydrochroride, once each day. After treatment of 3 weeks, changes of behaviors, plasma cortisol (COR) level and expressions of protein kinase A (PKA) and protein kinase C (PKC) in hippocampus were observed in the rats.
Results: In the depression model rats, the body weight increased slowly, and horizontal and vertical activities and consumption of sugar liquid significantly decreased; plasma cortisol content significantly increased; expressions of PKA and PKC in the hippocampus significantly reduced. In the rats of EA group, the score of behaviors, the consumption of sugar liquid and the increase of body weight were not significantly different to those in the model group, but the plasma cortisol level significantly decreased and closed to the normal level, and positive expressions of PKA and PKC in the hippocampus could be effectively reversed. In the Maprotiline group, the consumption of sugar liquid significantly increased and plasma cortisol level significantly decreased, and expressions of PKA and PKC in the hippocampus increased as compared with those in the model group.
Conclusion: The depression model rat has dysfunction of the hypothalamus-pituitary-adrenal axis (HPAA) and EA can regulate functions of HPAA. The mechanism is possibly carried out by regulating functions of relative enzymes in the signal transduction pathway in hippocampal cells.