title: Melanocortin-5 receptor deficiency in mice blocks a novel pathway influencing pheromone-induced aggression.
abstract: The rodent preputial gland secretes aggression-promoting pheromones and expresses melanocortin-5 receptor (MC5R), but the functional relationship is poorly understood. We investigated whether MC5R deficiency in male mice alters stimulatory melanocortin influences on preputial growth and pheromone-induced aggression. In wild-type (MC5R(+/+)) pairs, repeated NDP-MSH injection decreased attack latency and increased aggression in initial attackers. Similar NDP-MSH treatment in MC5R-deficient (MC5R(-/-)) pairs failed to alter attack latency or aggression frequency, but aggression increased in vehicle-injected opponents. NDP-MSH treatment promoted preputial hypertrophy, and in MC5R(+/+) mice paired against non-aggressive stimulus opponents it decreased attack latency and increased aggression. MC5R(-/-) mice were insensitive to behavioral and physiological effects of NDP-MSH, and preputialectomized mice were insensitive to behavioral effects of NDP-MSH. The results suggest that MC5R inactivation reduced a pheromonal signal for aggression that acts on donors, rather than their opponents.
authors.affiliation: Vollum Institute for Advanced Biomedical Research, Oregon Health and Science University, Portland, 97239, USA. cam2025@med.cornell.edu
authors.forename: Caurnel
authors.initials: C
authors.lastname: Morgan
authors.forename: Roger D
authors.initials: RD
authors.lastname: Cone
mesh_terms: D000374:Aggression / Q000502:physiology*; D000378:Agonistic Behavior / Q000502:physiology; D000818:Animals; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D010675:Pheromones / Q000502:physiology*; D018043:Receptors, Corticotropin / Q000172:deficiency* / Q000235:genetics; D044101:Receptors, Melanocortin; D000521:alpha-MSH / Q000502:physiology
chemical_list: D010675:Pheromones; D018043:Receptors, Corticotropin; D044101:Receptors, Melanocortin; C086971:melanocortin 5 receptor; D000521:alpha-MSH