Enkephalins-modulation of Plasmodium cynomolgi antigens-induced colony-stimulating factors elaboration by macrophages.
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.
Singh
P P
PP
Division of Microbiology, Central Drug Research Institute, Lucknow, India.
Singh
S
S
Dhawan
V C
VC
Haq
W
W
Mathur
K B
KB
Dutta
G P
GP
Srimal
R C
RC
Dhawan
B N
BN
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*
D000953:Antigens, Protozoan; D003115:Colony-Stimulating Factors; D004745:Enkephalins; D009270:Naloxone; D004744:Enkephalin, Methionine