Fig. 3. Effects of spinal muscarinic acetylcholine receptor subtype antagonists on EA-induced anti-allodynia.

The behavioral tests for cold allodynia were performed before the intrathecal injection of receptor antagonists and after EA treatment in four groups: (A) NS (n=4), (B) pirenzepine (n=6), (C) methoctramine (n=8), and (D) 4-DAMP (n=7). Methoctramine (M2 receptor antagonist), and 4-DAMP (M3 receptor antagonist) blocked the analgesic effect of EA, whereas, NS and pirenzepine (M1 receptor antagonist) did not block the analgesic effect of EA. Data are presented as mean±S.E.M.; ^**p<0.01; by paired t-test.