[The nervous system and the immune system: the role of morphine and opioid peptides in the function of neutrophilic granulocytes].

Inhibition of human granulocyte chemotaxis towards casein was observed in the presence of mu and k receptor agonist, which per se exhibits chemokinetic activity. Naloxone was found to prevent both the opioid and opioid unrelated increase of granulocyte migration. Although opioid agonists with different receptors specificity were capable of strongly modifying human granulocyte migration, no conclusion can be drawn on the role of opioid receptors in regulating migration activity. The effects of morphine and opioid peptide on neutrophil aggregation and ATOP release were studied. Inhibition of human granulocyte aggregation and ATP release was observed in the presence of morphine in a naloxone stereoselective manner, whereas the opioid peptides were ineffective. The effect of DAGO, DADL and dynorphin 1-9 on granulocyte aggregation and ATP release were also evaluated, but these opioid peptides are unable to modify neutrophil function. Our studies confirm the role of mu receptors on modulation of polymorphonuclear granulocyte function and suggest a key role of opioid peptides in the regulation of some immune system functions. In comparative studies Ca++ (A 23,187) and dynorphin 1-9, per se, induced stimulation of arachidonic acid metabolites from granulocytes. In this regard dynorphin 1-9 may function as a mediator between the central nervous system and immunity.