title: Inhibitory influences of MIF-1 (PLG) and Tyr-MIF-1 (YPLG) on aggression and defeat-induced analgesia in mice.
abstract: The effects of prolyl-leucyl-glycinamide (MIF-1, PLG), tyrosine-prolyl-leucyl-glycinamide (Tyr-MIF-1, YPLG) and the exogenous opiate antagonist, naloxone, on aggressive interactions and defeat-induced analgesia were examined in male mice. All three substances reduced the number of bites required to obtain defeat in subordinate mice during aggressive encounters, as well as blocking subsequent defeat-induced analgesia. Tyr-MIF-1 had significantly greater inhibitory effects than MIF. These results suggest that both MIF and Tyr-MIF-1 may function as endogenous opioid antagonists and have inhibitory influences on aggression, with the antagonistic effects of Tyr-MIF-1 being more potent than those of MIF-1.
mesh_terms: D000374:Aggression / Q000187:drug effects*; D000698:Analgesia; D000818:Animals; D004291:Dominance-Subordination; D009075:MSH Release-Inhibiting Hormone / Q000031:analogs & derivatives* / Q000494:pharmacology; D008297:Male; D051379:Mice; D009270:Naloxone / Q000494:pharmacology; D009842:Oligopeptides / Q000494:pharmacology*; D012930:Social Dominance
chemical_list: D009842:Oligopeptides; D009270:Naloxone; C029463:prolyl-lysyl-glycinamide; C036930:tyrosyl-prolyl-leucyl-glycinamide; D009075:MSH Release-Inhibiting Hormone