title: Aggressive interactions are associated with reductions in RFamide-related peptide, but not kisspeptin, neuronal activation in mice.
abstract: Aggressive interactions lead to changes in both future behavior and circulating testosterone (T) concentrations in animals across taxa. The specific neural circuitry and neurochemical systems by which these encounters alter neuroendocrine functioning are not well understood. Neurons expressing the inhibitory and stimulatory neuropeptides, RFamide-related peptide (RFRP) and kisspeptin, respectively, project to neural loci regulating aggression in addition to neuroendocrine cells controlling sex steroid production. Given these connections to both the reproductive axis and aggression circuitry, RFRP and kisspeptin are in unique positions to mediate post-encounter changes in both T and behavior. The present study examined the activational state of RFRP and kisspeptin neurons of male C57BL/6 mice following an aggressive encounter. Both winners and losers exhibited reduced RFRP/FOS co-localization relative to handling stress controls. Social exposure controls did not display reduced RFRP neuronal activation, indicating that this effect is due to aggressive interaction specifically rather than social interaction generally. RFRP neuronal activation positively correlated with latencies to display several offensive behaviors within winners. These effects were not observed in the anteroventral periventricular (AVPV) nucleus kisspeptin cell population. Together, these findings point to potential neuromodulatory role for RFRP in aggressive behavior and in disinhibiting the reproductive axis to facilitate an increase in T in response to social challenge.
authors.affiliation: Department of Psychology, University of California, Berkeley, CA, USA.
authors.forename: Kimberly J
authors.initials: KJ
authors.lastname: Jennings
authors.affiliation: Department of Psychology, University of California, Berkeley, CA, USA.
authors.forename: Jenny
authors.initials: J
authors.lastname: Chang
authors.affiliation: Department of Psychology, University of California, Berkeley, CA, USA.
authors.forename: Hweyryoung
authors.initials: H
authors.lastname: Cho
authors.affiliation: Department of Psychology, University of California, Berkeley, CA, USA.
authors.forename: David J
authors.initials: DJ
authors.lastname: Piekarski
authors.affiliation: Department of Psychology, University of California, Berkeley, CA, USA.
authors.forename: Kimberly A
authors.initials: KA
authors.lastname: Russo
authors.affiliation: Department of Psychology, University of California, Berkeley, CA, USA; The Helen Wills Neuroscience Institute, University of California, Berkeley, CA, USA. Electronic address: kriegsfeld@berkeley.edu.
authors.forename: Lance J
authors.initials: LJ
authors.lastname: Kriegsfeld
mesh_terms: D000374:Aggression / Q000502:physiology*; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D007032:Hypothalamus, Anterior / Q000378:metabolism*; D059648:Kisspeptins / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009474:Neurons / Q000378:metabolism*; D009479:Neuropeptides / Q000378:metabolism*
chemical_list: C491407:Kiss1 protein, mouse; D059648:Kisspeptins; D009479:Neuropeptides; C416987:RFamide peptide
keywords: Agonistic; Challenge effect; GnIH; Metastin; RFRP