title: Effects of mammalian FMRF-NH2-related peptides and IgG from antiserum against them on aggression and defeat-induced analgesia in mice.
abstract: The effects of two endogenous mammalian FMRFamide (Phe-Met-Arg-Phe-NH2)-related peptides, an octapeptide F8Fa (Phe-Leu-Phe-Gln-Pro-Gln-Arg-Phe-NH2) and an octadecapeptide A18Fa (Ala-Gly-Glu-Gly-Leu-Ser-Ser-Pro-Phe-Trp-Ser-Leu-Ala-Pro-Gln-Arg-Phe-NH2 ), and IgG from serum against them on the responses to aggression and defeat-induced analgesia were examined in subordinate mice in "resident-intruder" pairings. Intracerebroventricular (ICV) administrations of F8Fa and A18Fa (0.10-10 micrograms) reduced, in a dose-dependent manner, the number of bites to obtain defeat in the subordinate mice during the agonistic encounters, as well as attenuating defeat-induced analgesia, with F8Fa having a greater inhibitory effect than A18Fa. Peripheral administration of naloxone (1.0 mg/kg) had a similar inhibitory effect on the number of bites to defeat and the level of defeat-induced analgesia. In contrast, ICV administrations of F8Fa-IgG and A18Fa-IgG antisera increased the number of bites to defeat and augmented the levels of defeat-induced analgesia, with F8Fa-IgG having a greater effect than A18Fa-IgG. These results provide further evidence that the peptides, F8Fa and A18Fa, are involved in the modulation of opioid-mediated analgesia accompanying biological stressors and suggest that these endogenous FMRF-NH2-related peptides may also be associated with the expression of opioid-sensitive components of aggressive behavior.
authors.affiliation: Division of Oral Biology, Faculty of Dentistry, University of Western Ontario, London, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Kavaliers
authors.forename: H Y
authors.initials: HY
authors.lastname: Yang
mesh_terms: D000374:Aggression / Q000187:drug effects* / Q000502:physiology; D000595:Amino Acid Sequence; D000698:Analgesia; D000818:Animals; D019835:FMRFamide; D007074:Immunoglobulin G / Q000494:pharmacology; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D009479:Neuropeptides / Q000037:antagonists & inhibitors / Q000494:pharmacology* / Q000502:physiology; D009619:Nociceptors / Q000187:drug effects / Q000502:physiology; D009842:Oligopeptides / Q000737:chemistry / Q000494:pharmacology* / Q000502:physiology
chemical_list: D007074:Immunoglobulin G; D009479:Neuropeptides; D009842:Oligopeptides; D019835:FMRFamide; C053651:phenylalanyl-leucyl-phenylalanyl-glutaminyl-prolyl-glutaminyl-arginyl-phenylalaninamide; C061209:A18Famide