The analgesic effects of EA on acute thermal pain were quantified using the TFL test, and they are expressed as percent changes from basal TFL. Either 2 Hz (A) or 100 Hz (B) EA, rats showed individual differences in sensitivity of EA analgesia for two consecutive days. A majority of rats showed sensitivity to EA analgesia (TFL change >0) and a small part appeared in contrary way (TFL change ≤0). Plan C and D showed comparison of the EA analgesic effects among the high-responder (HR), responder (R), and non-responder (NR) or restraint (Res) group in two consecutive days. Data are represented as mean ± SEM. One way ANOVA and Bonferroni’s Multiple Comparison Test was used to analysis TFL change (%). *P<0.05, **P<0.01, ***P<0.001 vs. restraint group; ###
P<0.001, vs. compared with the corresponding NR group; &&&
P<0.001, compared with the corresponding R groups.