SUPPRESSION OF PERITONEAL MACROPHAGE PHAGOCYTOSIS OF CANDIDA-ALBICANSBY OPIOIDS

Receptor-selective opioid agonists have been found to suppress the cap acity of macrophages to ingest opsonized sheep erythrocytes. In an eff ort to characterize the immunomodulatory activity of opioids further, experiments were done to examine the uptake of Candida albicans by opi oid-treated murine peritoneal macrophages. It was found that treatment with morphine and selective mu, i.e., DAMGO, delta, i.e., DPDPE, and kappa, i.e., trans-3,4-dichloro-N-methyl-N-[2-(1-pyrrolidinyl) cyclohe xyl]benzene-acetamide methanesulfonate, receptor agonists resulted a c oncentration-dependent suppression of both the percentage of phagocyti c cells and the average number of ingested yeasts. Antagonists selecti ve for mu, i.e., H-D-Phe-Cys-Tyr-o-Trp-Arg-Thr-Pen-Thr-NH2, delta, i.e ., naltrindole, and kappa, i.e., norbinaltorphimine, opioid receptors completely blocked the respective receptor-selective agonist-induced s uppression. These results suggest that the mu, delta and kappa opioid receptors can modulate macrophage function.