Our previous study suggested that peripheral sympathetic nerve played an important role in the electroacupuncture (EA)-induced irnrnunomodulation. The aim of this study is to explore the role of peripheral parasympathetic nerve in it. All mice are preimmunized with SRBC (sheep red blood cell) 4 days before experiment. The animals in different groups were injected i. p. with Hemicholine-3 (HC-3

an ACh synthesis blocker) or physiological saline 3 hr before EA. The main results are as follows: 1. In saline group

the LTT (lymphocyte transformation test)

IL-2 (interleukin-2 ) of spleen and lymphocyte number of thymus are rnarkedly increased

and the other immune parameters have no change after EA.2. In HC-3 control group

the LTT

IL-2 are decreased significantly and the other immune parameters have not shown influence.3. In the HC-3 with EA group

the magnitude of LTT

lL-2 did not significantly change as compared with HC-3 alone

it is especially noteworthy that the other unchanged parameters by HC-3 such as spleen weight

spleen index

thymus weight

thymus index

number of spleen cells

spleen LZM(lysozyrne) and thymus LZM are clearly decreased after EA.The above results suggest that peripheral parasympathetic nerve may play some prornoting effect in the EA-induced immunomodulation. Its effect may be mediated by ACh released from parasympathetic nerve endings