title: Differential alteration of functions of rat peritoneal macrophages responsive to endogenous opioid peptide endomorphin-1.
abstract: Endomorphin-1 is a recently isolated endogenous opioid peptide, and potent and selective high affinity mu-opioid receptor agonist. We evaluate the role of endomorphin-1 on macrophage functions. Endomorphin-1 potentiated macrophage adhesion and the expression of adhesion molecule Mac-1 on macrophages. However, endomorphin-1 did not alter phagocytosis of Escherichia coli by macrophages. Moreover, endomorphin-1 inhibited macrophage chemotaxis and the production of superoxide anion by macrophages. On the contrary, endomorphin-1 inhibited TNF-alpha production by macrophages stimulated with both LPS and PMA, respectively. Similarly, endomorphin-1 suppressed IL-10 and IL-12 productions in response to LPS. In contrast, endomorphin-1 potentiated IL-1beta production by macrophages stimulated with PMA. These results suggest that endomorphin-1 may alter macrophage functions such as cytokine productions and functions related to natural host defense.
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D017737:Macrophages, Peritoneal / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D008297:Male; D009842:Oligopeptides / Q000494:pharmacology*; D018847:Opioid Peptides / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D009842:Oligopeptides; D018847:Opioid Peptides; C105293:endomorphin 1