Morphine treatment in vitro or in vivo decreases phagocytic functions of murine macrophages

• Published in: Life sciences (1973) Vol. 53; no. 12; pp. 997 - 1006
• Main Authors: Rojavin, Mikhail, Szabo, Imre, Bussiere, Jeanine L., Rogers, Thomas J., Adler, Martin W., Eisenstein, Toby K.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 1993; Elsevier
• Subjects: Animals; Biological and medical sciences; Candida albicans - immunology; Depression, Chemical; Drug Interactions; Female; Fundamental and applied biological sciences. Psychology; Fundamental immunology; Immunobiology; Macrophages - drug effects; Macrophages - immunology; Mice; Mice, Inbred C3H; Modulation of the immune response (stimulation, suppression); Morphine - antagonists & inhibitors; Morphine - pharmacology; Naltrexone - pharmacology; Peritoneal Cavity - cytology; Phagocytosis - drug effects; Time Factors; Opiate receptor; Vertebrata; Immunosuppression; Mammalia; Immune response; Mouse; Rodentia; Morphine; Opiates; Phagocytosis; Macrophage
• ISSN: 0024-3205; 1879-0631
• DOI: 10.1016/0024-3205(93)90122-J

Studies were performed to compare in vitro and in vivo effects of morphine on the phagocytic function of murine peritoneal macrophages. Macrophage monolayers were incubated with Candida albicans for 30 min in the absence of autologous serum. Morphine added in vitro was found to decrease both the phagocytic activity (percent of phagocytic cells) and the phagocytic index (average number of ingested yeasts per cell) in a concentration-dependent manner, with maximal effects of 26% and 41%, respectively, at 10 −6 M. When morphine was administered in vivo via an implanted 75-mg pellet, there was a 22% decrease in phagocytic activity and a 40% decrease in the phagocytic index. Naltrexone completely blocked the effects of morphine both in vitro and in vivo. The results suggest that morphine is capable of interacting directly with opioid receptors on macrophages, resulting in a decrease in phagocytic function.