Opioids immunomodulation

According to the NC-IUPHAR Subcommittee on Opioid Receptois it was proposed to term ORL-1 recqrtor as NOP receptor [1]. The human NOP receptor gene encodes a protein of370 amino acids. Splice valiants have been found in the human and mouse NOP recqrtor with no known functional significance. NOP receptors are widely distributed throughout the brain and in the spinal cord. They are also present in immune cells. A functional role for N/OFQ has been proposed in nociception, locomotoric activity, reward, stress, and immunomodulation. 

Perez, L. and Lysle, D.T., Conditioned immunomodulation Investigations of the role of endogenous activity at mu, kappa, and delta opioid receptor subtypes, J. Neuroimmunol.,19, 101,1997. 

Such events show how the immune, endocrine and central nervous systems are integrated in their responses to any form of stress. It is well established that physical or psychosocial stress causes increased secretions of prolactin, growth hormones, thyroid, and gonadal hormones, in addition to ACTH. Endogenous opioids are secreted under such conditions and function as immunomodulators, while also elevating the pain threshold. Receptors for such hormones exist on immunocompetent cells, along with receptors for catecholamines, serotonin and acetylcholine. 

The direct effects opioid and opioidlike peptides exhibit on cells of the immune system is both varied and, in some instances, contradictory, depending on which receptor subtype is being studied. Mu and kappa receptors generally affect immunofunction in a suppressive manner, where delta receptors tend to express immunostimulation [82-85]. However, selected delta antagonists have shown to elicit suppressive effects on B-cell proliferation, NK cell activity, and T-helper cell cytokine production [86]. The alteration of leukocyte function via opioid receptors will be discussed highlighting specific cell subtype immunomodulation. Endorphin shows a inhibitory effect on splenocyte proliferation through central and peripheral autocrine/paracrine pathways [87]. 

OPIOIDS ANTICANCER AND IMMUNOMODULATING DRUGS - CYTOTOXICS 1. Imatinib may cause t plasma concentrations, with a risk of toxic effects of codeine, dextromethorphan, hydroxycodone, methadone, morphine, oxycodone, pethidine and tramadol 2. Unpredictable reactions may occur associated with hypotension and respiratory depression when procarbazine is co-administered with alfentanil, fentanyl, sufentanil or morphine... 

Delta Opioid Receptor Agonist Compounds as Immunomodulators... 

Potential of Kappa Opioid Receptor Agonists To Produce Immunomodulation... 

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