Naloxone and electroacunpunture (EA) improve the immune function of traumatized rats

The present study was undertaken to examine the effects of intracerebroventricular (icv) injection of naloxone (an antagonist of opioid receptors) and electroacupuncture (EA) on the natural killer (NK) cell activity, lymphocyte proliferation and induction of interleukin-2 (IL-2) production of spleen lymphocytes of surgically traumatized rats. The NK cell activity, the spleen lymphocyte proliferation and the induction of IL-2 production were all significantly inhibited following traumatization. Compared to the traumatic group, the inhibition of the NK cell activity and the induction of IL-2 production were antagonised by icv injection of naloxone. EA stimulation of Zusanli (St 36) and Lanwei (Extra 33) points reduced the immunosuppression produced by trauma. The above results show that the central endogenous opioid peptidergic system may play an important role in immunosuppression. It is suggested that the endogenous opioid peptidergic system might act as an important modulatory system between CNS and the immune system.