1. Morphine modulation of plasmodial-antigens-induced colony-stimulating factors production by macrophages.
- Author
-
Singh S and Singh PP
- Subjects
- Analgesics, Opioid immunology, Animals, Cycloheximide pharmacology, Dose-Response Relationship, Immunologic, Drug Interactions, Enkephalin, Ala(2)-MePhe(4)-Gly(5)- pharmacology, Enkephalin, D-Penicillamine (2,5)- pharmacology, Female, Kinetics, Macrophages, Peritoneal drug effects, Macrophages, Peritoneal immunology, Male, Mice, Mice, Inbred BALB C, Morphine immunology, Naloxone pharmacology, Narcotic Antagonists pharmacology, Protein Synthesis Inhibitors pharmacology, Receptors, Opioid, delta agonists, Receptors, Opioid, mu agonists, Adjuvants, Immunologic pharmacology, Analgesics, Opioid pharmacology, Antigens, Protozoan biosynthesis, Colony-Stimulating Factors biosynthesis, Macrophages, Peritoneal metabolism, Morphine pharmacology, Plasmodium berghei immunology
- Abstract
Morphine abuse is known to cause immunosuppression and enhanced host susceptibility to malaria. We studied the effect of morphine on the Plasmodium berghei total-parasite-antigens soluble in culture medium (P.b.SA)-induced production of colony-stimulating factors (CSFs) by mouse peritoneal macrophages, in vitro. Morphine exerted a concentration-dependent biphasic modulatory effect; at 1 x 10(-4)-1 x 10 x 10(-6) M it slightly inhibited, whereas at 1 X 10(-8)-1 x 10(-10) M it augmented the production of CSFs. However, at 1 x 10(-12) M concentration the augmenting effect of morphine was significantly (p<0.05) diminished. Selective agonists of delta- (DPDPE) and mu- (DAGO) opioid receptors also respectively, inhibited and augmented the production of CSFs. The CSFs appear to be synthesized de novo as cycloheximide (50.0 microg/ml) completely inhibited their production. Naloxone ( 1 x 10(-5) M) lacked any effect on the inhibitory effect of morphine; however, at 1 x 10(-3) M it exerted partial blocking effect. Conversely, at 1 x 10(-5) M naloxone significantly (p<0.05) blocked the augmenting effect of morphine. These results suggest that morphine via opioid receptors, in a concentration-dependent biphasic manner, modulated the P.b.SA-induced de novo production of CSFs by macrophages, in vitro.
- Published
- 2000
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