title: Immunomodulation of the neutrophil respiratory burst by endomorphins 1 and 2.
abstract: Opioid peptides were found to be released from cells of the immune system during inflammation and stress, and were associated with altered immune responses. Production of superoxide anions by PMA-stimulated neutrophils was markedly inhibited in a concentration-dependent manner by preincubation for 15 min with 10(-18) - 10(-6) M of the endogenous opioid peptides endomorphin 1 or 2. Inhibition was prevented by prior treatment with the micro-opioid receptor-selective antagonist beta-funaltrexamine at 10(-12) - 10(-8) M, but not the delta-opioid receptor-selective antagonist naltrindole. In contrast, endomorphins 1 and 2 caused significant potentiation of superoxide anion production in unstimulated neutrophils. These results suggest that the endogenous opioid peptides endomorphins 1 and 2 may modulate the production of superoxide anions in neutrophils via mu-opioid receptors.
authors.affiliation: Department of Pharmacology, Osaka Dental University, Hirakata, Japan. aazuma@cc.osaka-dent.ac.jp
authors.forename: Y
authors.initials: Y
authors.lastname: Azuma
authors.forename: P L
authors.initials: PL
authors.lastname: Wang
authors.forename: M
authors.initials: M
authors.lastname: Shinohara
authors.forename: K
authors.initials: K
authors.lastname: Ohura
mesh_terms: D000818:Animals; D005786:Gene Expression Regulation; D008297:Male; D018375:Neutrophil Activation; D009504:Neutrophils / Q000276:immunology* / Q000378:metabolism; D009842:Oligopeptides / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D016897:Respiratory Burst / Q000187:drug effects*; D013481:Superoxides / Q000378:metabolism*
chemical_list: D009842:Oligopeptides; C105293:endomorphin 1; D013481:Superoxides; C105294:endomorphin 2