title: Enkephalins-modulation of Plasmodium cynomolgi antigens-induced colony-stimulating factors elaboration by macrophages.
abstract: Methionine-enkephalin (M-Enk) and its analogue compound 82/205 (10(-5) and 10(-6) M) inhibited elaboration of Plasmodium cynomolgi total antigens soluble in culture medium (P.c.SA)-induced colony-stimulating factors (CSFs) by monkey blood monocyte-derived macrophages, in vitro. Paradoxically, lower concentrations (10(-7)-10(-9) M) of both the peptides greatly augmented CSFs elaboration; 82/205 appeared to be nearly 2.3-fold more potent. Naloxone (10(-5) M) pretreatment of macrophages inhibited only the M-Enk- and 82/205-induced enhanced CSFs elaboration, suggesting an opiate receptors-mediated mechanism of action. None of the peptides or naloxone (10(-5)-10(-9) M) had any direct effect on the CSF elaboration by unstimulated macrophages.
authors.affiliation: Division of Microbiology, Central Drug Research Institute, Lucknow, India.
authors.forename: P P
authors.initials: PP
authors.lastname: Singh
authors.forename: S
authors.initials: S
authors.lastname: Singh
authors.forename: V C
authors.initials: VC
authors.lastname: Dhawan
authors.forename: W
authors.initials: W
authors.lastname: Haq
authors.forename: K B
authors.initials: KB
authors.lastname: Mathur
authors.forename: G P
authors.initials: GP
authors.lastname: Dutta
authors.forename: R C
authors.initials: RC
authors.lastname: Srimal
authors.forename: B N
authors.initials: BN
authors.lastname: Dhawan
mesh_terms: D000818:Animals; D000953:Antigens, Protozoan / Q000276:immunology*; D003115:Colony-Stimulating Factors / Q000096:biosynthesis*; D004744:Enkephalin, Methionine / Q000494:pharmacology; D004745:Enkephalins / Q000494:pharmacology*; D005260:Female; D008253:Macaca mulatta; D008264:Macrophages / Q000378:metabolism*; D008297:Male; D009270:Naloxone / Q000494:pharmacology; D016789:Plasmodium cynomolgi / Q000276:immunology*
chemical_list: D000953:Antigens, Protozoan; D003115:Colony-Stimulating Factors; D004745:Enkephalins; D009270:Naloxone; D004744:Enkephalin, Methionine