Detection Of Opioid Receptors On Cells From Immune System

Object: To search for histological evidence for the existence of opioid receptors on cells from the immune system, and to reveal the integral link between the neuroendocrine system and the immune system, and probe into the pattern and the mechanisms of the effect. Methods: The expression of kappa-opioid receptor(KOR), mu-opioid receptor(MOR) and delta-opioid receptor(DOR) were detected by immunohistochemistry in cryostat sections in eighty-two cases of lymphoid tissues. The mRNA of DOR was detected by in situ hybridiation in cryostat sections in twenty cases of lymphoid tissues. The brains of rats were used as positive comparision11'. Results: The positive rates of DOR on cells from the immune system were 80.49%(66/82) by immunohistochemistry and 75.00%( 15/20) by in situ hybridiation, and the two rates showed no significant difference(X2=0.2636, P>0.05). The positive rates of KOR, MOR and DOR by immunohistochemistry respectively were 76.83%(63/82), 85.37%(70/82) and 80.49%(66/82). There are no significant difference between the three rates (X2= 1.946, P > 0.05) and the positive rates of the same receptor in different lymphoid tissue showed high correlation (KOR: X2=1.0722, P>0.05; MOR: X2=7.1833, P>0.05; DOR: X2=5.7648, P>0.05) .Conclusion: Opioid receptors indeed exist on immune cells and opioid may have a direct effect on immune responses, acting through opioid receptors on immune cells. The sensitivities of immunohistochemistry and hi situ hybridiation on detecting the opioid receptors have no significant difference and the expression of opioid receptors in differentlymphoid tissue showed no significant difference, too.