title: Defensive responses of Brandt's voles (Lasiopodomys brandtii) to chronic predatory stress.
abstract: Predator odors are non-intrusive natural stressors of high ethological relevance. The objective of this study was to investigate the processing of a chronic, life-threatening stimulus during repeated prolonged presentation to Brandt's voles. One hundred and twenty voles were tested by repeated presentation of cat feces in a defensive withdrawal apparatus. Voles exposed to feces for short periods showed more avoidance, more concealment in the hide box, less contact time with the odor source, more freezing behavior, less grooming, more jumping, and more vigilant rearing than did non-exposed voles, and those exposed for longer periods. Serum levels of adrenocorticotropic hormone and corticosterone increased significantly when animals were repeatedly exposed to cat feces for short periods. The behavioral and endocrine responses habituated during prolonged presentation of cat feces. ΔfosB mRNA expression level was highest in voles exposed to cat feces for 6 and 12 consecutive days, and subsequently declined in animals exposed to cat feces for 24 days. We therefore conclude that the behavioral and endocrine responses to repeated exposure to cat feces undergo a process of habituation, while ΔfosB changes in the medial hypothalamic region exhibit sensitization. We propose that habituation and sensitization are complementary rather than contradictory processes that occur in the same individual upon repeated presentation of the same stressor.
authors.affiliation: Department of Animal Behavior, College of Bioscience and Biotechnology, Yangzhou University, Yangzhou 225009, Jiangsu, China.
authors.forename: Ibrahim M
authors.initials: IM
authors.lastname: Hegab
authors.affiliation: Department of Animal Behavior, College of Bioscience and Biotechnology, Yangzhou University, Yangzhou 225009, Jiangsu, China.
authors.forename: Guoshen
authors.initials: G
authors.lastname: Shang
authors.affiliation: Department of Animal Behavior, College of Bioscience and Biotechnology, Yangzhou University, Yangzhou 225009, Jiangsu, China.
authors.forename: Manhong
authors.initials: M
authors.lastname: Ye
authors.affiliation: Department of Animal Behavior, College of Bioscience and Biotechnology, Yangzhou University, Yangzhou 225009, Jiangsu, China.
authors.forename: Yajuan
authors.initials: Y
authors.lastname: Jin
authors.affiliation: Department of Animal Behavior, College of Bioscience and Biotechnology, Yangzhou University, Yangzhou 225009, Jiangsu, China.
authors.forename: Aiqin
authors.initials: A
authors.lastname: Wang
authors.affiliation: Department of Animal Behavior, College of Bioscience and Biotechnology, Yangzhou University, Yangzhou 225009, Jiangsu, China.
authors.forename: Baofa
authors.initials: B
authors.lastname: Yin
authors.affiliation: Department of Animal Behavior, College of Bioscience and Biotechnology, Yangzhou University, Yangzhou 225009, Jiangsu, China.
authors.forename: Shengmei
authors.initials: S
authors.lastname: Yang
authors.affiliation: Department of Animal Behavior, College of Bioscience and Biotechnology, Yangzhou University, Yangzhou 225009, Jiangsu, China. Electronic address: whwei@yzu.edu.cn.
authors.forename: Wanhong
authors.initials: W
authors.lastname: Wei
mesh_terms: D000324:Adrenocorticotropic Hormone / Q000097:blood; D000818:Animals; D003411:Arvicolinae / Q000502:physiology* / Q000523:psychology*; D002415:Cats; D003345:Corticosterone / Q000097:blood; D003674:Defense Mechanisms; D005243:Feces; D005786:Gene Expression Regulation / Q000502:physiology; D007031:Hypothalamus / Q000378:metabolism; D009812:Odorants; D016760:Proto-Oncogene Proteins c-fos / Q000235:genetics / Q000378:metabolism; D013315:Stress, Psychological / Q000097:blood / Q000473:pathology / Q000523:psychology
chemical_list: D016760:Proto-Oncogene Proteins c-fos; D000324:Adrenocorticotropic Hormone; D003345:Corticosterone
keywords: Behavior; Brandt's voles; Cat feces; Endocrine; Medial hypothalamus; Repeated stress; ΔfosB mRNA