Opioid peptides found in the general circulation can modulate several functions of phagocytic cells that are related to their microbicidal and cytotoxic activity. Since reactive oxygen species are crucial to these activities, the affect of opioid peptides on superoxide (O-2) generation was evaluated with the use of lucigenin-enhanced chemiluminesence (CL). beta-Endorphin and dynorphin stimulate the production of O-2 in human polymorphonuclear leukocytes (PMN) and peritoneal macrophages (PMO) at peptide concentrations that prevail systemically (10(-14)-10(-12)M). There is an inverse dose-response relation for PMN but not PMO. The effect is rapid and sustained in PMN (peak CL at 2-4 min, duration greater than 15 min), whereas it is rapid but brief in PMO (peak 1 min, duration less than 3 min). Naloxone inhibits CL responses by greater than 75% in both cell types.

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Recent studies of the antimicrobial capacity of peritoneal macrophages (PM4+) isolated from patients undergoing chronic peritoneal dialysis have raised the question of whether these cells might be analogous to stimulated or activated murine PM+. To explore this possibility, we compared PM+ from these patients (dialysate-elicited PM+) with PM4 obtained from women undergoing laparoscopy (resident PM4) in several in vitro assays of phagocyte function. Although bacterial phagocytosis by cells from both groups of donors was similar, significant differences were found in their chemiluminescence responses to opsonized zymosan.Although the mean peak luminol-enhanced chemiluminescence response of dialysate-elicited PM+ was 4.7 x 105 cpm, that of resident PM4 was only 1.3 x 105 cpm (P < 0.05). In a lucigenin-enhanced chemiluminescence assay, dialysate-elicited PM4 again generated significantly greater chemiluminescence than did resident PM4, 212 on July 4, 2020 by guest http://iai.asm.org/ Downloaded from Immun. 24:932-938. 45. Seim, S. 1983. Role of myeloperoxidase in the luminol-dependent chemiluminescence response of phagocytosing human VOL. 49, 1985 on July 4, 2020 by guest http://iai.asm.org/ Downloaded from