Endogenous opioids and immunocompetence

In the last years multidisciplinary studies are being undertaken to deal with the interesting correlation between the immune and neuroendocrine system. Neurochemical changes induced by stress activate some hormones and peripheral neurotransmitters which in turn, are able to influence directly the immune function according to immunomodulation circuits. Bidirectional communication between the immune system and neuroendocrine system occurs as a result of hormones and receptors that are common to both system. The immune system besides representing an important target of opioid peptides could be considered a mobile part of the nervous system. In fact has been demonstrated that immunocompetent cells produce cytokines and neuropeptides which are able to interact with specific receptors present in the neuroendocrine system, and that neuroendocrine cells produce cytokines having an immunomodulating effect. In addition the recent observations that inherited defect of the human complement system could be associated with an increased level of PMOC's products, suggests a new and exiting interaction between the immune and the central nervous systems. The molecular basis of the bidirectional link between stress and immunomodulation has been identified in the opioid peptides complex hormone system deriving from three large prohormones: prodynorphin, proenkephalin and proopiomelanocortin (POMC) with opiate like biological property.