Arginase activity in cells harvested from the peritoneal cavity of EA-treated mice. Mice were treated with EA (15/30 Hz) at the Zusanli acupoint (ST36) for 20 min/d for 5 d (A) or 10 d (B). After the final EA session, the mice were euthanized and their peritoneal cells were harvested for evaluation by the arginase assay. The data are represented as mean ± SD of urea production per lysate of 1 × 106 cells. The sham-treated mice received only needle insertion into a non-acupoint (gluteal muscle) without electrical stimulation. There were nine mice in each group.