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Neuroendocrinology Letters incl. Psychoneuroimmunology & Chronobiology

including Psychoneuroimmunology, Neuro
Reproductive Medicine, Chronobiology
and Human Ethology
ISSN 0172–780X

NEL VOL. 22 No. 6
Invited NEL Review

Neuroimmunology of Opioids from Invertebrates to Human

2001; 22:467-474
pii: NEL220601R05

full text pdf (190kb)

Neuroimmunology of Opioids from Invertebrates to Human

by Michel Salzet

neuroimmunology; opiods; invertebrates; human; antibacterial

Submitted: December 8, 2001
Accepted: December 10, 2001


There is today growing evidence that the nervous and the immune systems can exchange information, mainly through small molecules, either cytokines or neuropeptides. Furthermore, it appears that some so-called neurotransmitters like neuropeptides can function as endogenous messengers of the immune system, and that they most likely participate in an important part in the regulation of the various components of the immune response. In this context, it is widely accepted that all organisms have processes that maintain their state of health. Failure of these processes, such as those involving naturally occurring antibacterial peptides, may lead to pathological events. The presence of antibacterial peptides on both proenkephalin invertebrate (Leeches) and vertebrate (Human) neuropeptide precursors such like enkelytin, peptide B, further supports the hypothesis that some of neuropeptide precursors are implicated in immune response. Indeed, their peptides, with their high antibacterial activities further associate opioid peptides with immune related activities. We surmise that immune signalling molecule may lead to enhanced proenkephalin proteolytic processing by prohormone convertase freeing both opioid peptides and antibacterial peptides during innate immune response. However, because it is necessary to modulate inflammation, invertebrates like leeches are also able to synthesize panoply of messengers that modulate inflammation e.g. endocannabinoids, opiates and pro-opiomelanocortin derived peptides such like adenocorticotrophin and melanostimulating hormone. This demonstrates that the equilibrium between the stimulation and the inhibition of the immune response has evolved sooner that it can be thought.


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