title: Fighting experience alters brain androgen receptor expression dependent on testosterone status.
abstract: Contest decisions are influenced by the outcomes of recent fights (winner-loser effects). Steroid hormones and serotonin are closely associated with aggression and therefore probably also play important roles in mediating winner-loser effects. In mangrove rivulus fish, Kryptolebias marmoratus, individuals with higher testosterone (T), 11-ketotestosterone and cortisol levels are more capable of winning, but titres of these hormones do not directly mediate winner-loser effects. In this study, we investigated the effects of winning/losing experiences on brain expression levels of the receptor genes for androgen (AR), oestrogen α/β (ERα/β), glucocorticoid (GR) and serotonin (5-HT1AR). The effect of contest experience on AR gene expression depended on T levels: repeated losses decreased, whereas repeated wins increased AR gene expression in individuals with low T but not in individuals with medium or high T levels. These results lend strong support for AR being involved in mediating winner-loser effects, which, in previous studies, were more detectable in individuals with lower T. Furthermore, the expression levels of ERα/β, 5-HT1AR and GR genes were higher in individuals that initiated contests against larger opponents than in those that did not. Overall, contest experience, underlying endocrine state and hormone and serotonin receptor expression patterns interacted to modulate contest decisions jointly.
authors.affiliation: Department of Life Science, National Taiwan Normal University, 88, Section 4, Ting-Chou Road, Taipei 11677, Taiwan, Republic of China.
authors.forename: Cheng-Yu
authors.initials: CY
authors.lastname: Li
authors.affiliation: Department of Biological Sciences, University of Alabama, 300 Hackberry Lane, Tuscaloosa, AL 35401, USA.
authors.forename: Ryan L
authors.initials: RL
authors.lastname: Earley
authors.affiliation: Department of Life Science, National Taiwan Normal University, 88, Section 4, Ting-Chou Road, Taipei 11677, Taiwan, Republic of China.
authors.forename: Shu-Ping
authors.initials: SP
authors.lastname: Huang
authors.affiliation: Department of Life Science, National Taiwan Normal University, 88, Section 4, Ting-Chou Road, Taipei 11677, Taiwan, Republic of China yuyinghs@ntnu.edu.tw.
authors.forename: Yuying
authors.initials: Y
authors.lastname: Hsu
mesh_terms: D000374:Aggression; D000818:Animals; D001522:Behavior, Animal; D001921:Brain / Q000378:metabolism; D003163:Competitive Behavior; D003220:Conflict, Psychological; D003532:Cyprinodontiformes / Q000378:metabolism / Q000502:physiology*; D005786:Gene Expression Regulation; D006854:Hydrocortisone / Q000378:metabolism; D011944:Receptors, Androgen / Q000378:metabolism*; D011960:Receptors, Estrogen / Q000378:metabolism; D011965:Receptors, Glucocorticoid / Q000378:metabolism; D011985:Receptors, Serotonin / Q000378:metabolism; D013739:Testosterone / Q000031:analogs & derivatives / Q000378:metabolism*
chemical_list: D011944:Receptors, Androgen; D011960:Receptors, Estrogen; D011965:Receptors, Glucocorticoid; D011985:Receptors, Serotonin; D013739:Testosterone; C003600:11-ketotestosterone; D006854:Hydrocortisone
keywords: 5-HT1A receptor; Kryptolebias marmoratus; hormone receptor; testosterone; winner/loser effect