30 adult SD rats were divided into 3 grous: normal control goup; SRBC immune group (on 5th day after SRBC injection) and MSG(MSG injection at newborn stage) + SRBC group. The changes of the spontaneous firing rates of ventromedial hypothalamus (VMH) neurons and evoked responses by electroacupuncture (EA) and locus coeruleus (LC) stimulation were recorded. The results were as follows: (1) The spontaneous firing rate of VMH neurons was significant increase in the SRBC group. The firing rate in the MSG + SRBC group was higher than that in the control group, and lower than that in the SRBC group. There were statistical differences between them. (2) EA can increase the firing rates in all groups. The effect of EA was the most significant in the SRBC group, and more significant in the MSG + SRBC group. (3) The firing type of most VMH neurons showed first excited then inhibited biphasic response following stimulation LC in the SRBC and the MSG + SRBC groups. EA showed some increase in effect of the excited modulation from LC to VMH in the SRBC group. The results suggest that VMH might be an important neuroendocrinal link in immunoresponse. EA can increase the immune function of SRBC on VMH. LC and beta-endorphine neurons of arcuate nucleus might participate in the EA mediated immunoresponse.