Effects of injection of anti-corticotropin release hormone serum in the lateral ventricles and electroacupuncture analgesia on pain threshold in rats with adjuvant arthritis

Rat models of adjuvant arthritis were established, and anti-corticotropin release hormone serum injection in the lateral ventricles and electroacupuncture at right Jiaji （EX-B2） were performed. The pain threshold was decreased at 45 and 60 minutes after injection of the anti-corticotropin release hormone serum. Electroacupuncture at Jiaji can resist this effect. Immunohistochemical staining results showed that the expression of corticotropin release hormone in the hypothalamic paraventdcular nucleus was greater in the electroacupuncture ＋ anti-corticotropin release hormone serum group compared with the anti-corticotropin release hormone serum group. The expression of corticotropin release hormone was correlated with the pain threshold. The effect of endogenous corticotropin release hormone in pain modulation can be obstructed by anti-corticotropin release hormone serum. The analgesia of electroacupuncture can partially resist the depressed pain threshold caused by injection of anti-corticotropin release hormone serum. The analgesic effect of electroacupuncture is associated with the corticotropin release hormone content in the hypothalamus.