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Dart DA, Bevan CL, Uysal-Onganer P, Jiang WG. Analysis of androgen receptor expression and activity in the mouse brain. Sci Rep 2024; 14:11115. [PMID: 38750183 PMCID: PMC11096401 DOI: 10.1038/s41598-024-61733-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Accepted: 05/09/2024] [Indexed: 05/18/2024] Open
Abstract
Androgen deprivation therapy (ADT) is the core treatment for advanced prostate cancer (PCa), with a proven survival benefit. ADT lowers circulating testosterone levels throughout the body, but with it comes a variety of reported side effects including fatigue, muscle wastage, weight gain, hot flushes and importantly cognitive impairment, depression, and mood swings. Testosterone has a key role in brain masculinization, but its direct effects are relatively poorly understood, due both to the brain's extreme complexity and the fact that some of testosterone activities are driven via local conversion to oestrogen, especially during embryonic development. The exact roles, function, and location of the androgen receptor (AR) in the adult male brain are still being discovered, and therefore the cognitive side effects of ADT may be unrecognized or under-reported. The age of onset of several neurological diseases overlap with PCa, therefore, there is a need to separate ADT side effects from such co-morbidities. Here we analysed the activity and expression level of the AR in the adult mouse brain, using an ARE-Luc reporter mouse and immunohistochemical staining for AR in all the key brain regions via coronal slices. We further analysed our data by comparing to the Allen Mouse Brain Atlas. AR-driven luciferase activity and distinct nuclear staining for AR were seen in several key brain areas including the thalamus, hypothalamus, olfactory bulb, cerebral cortex, Purkinje cells of the cerebellum and the hindbrain. We describe and discuss the potential role of AR in these areas, to inform and enable extrapolation to potential side effects of ADT in humans.
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Affiliation(s)
- D Alwyn Dart
- UCL (University College London) Cancer Institute, University College London, Paul O'Gorman Building, 72 Huntley Street, London, WC1E 6DD, UK.
- Department of Surgery and Cancer, Imperial Centre for Translational and Experimental Medicine, Imperial College London, London, W12 0NN, UK.
- Cardiff China Medical Research Collaborative, School of Medicine, Cardiff University, Cardiff, CF14 4YS, UK.
| | - Charlotte L Bevan
- Department of Surgery and Cancer, Imperial Centre for Translational and Experimental Medicine, Imperial College London, London, W12 0NN, UK
| | - Pinar Uysal-Onganer
- Cancer Mechanisms and Biomarkers Research Group, School of Life Sciences, College of Liberal Arts and Sciences, University of Westminster, 115 New Cavendish Street, London, W1W 6UW, UK
| | - Wen Guo Jiang
- Cardiff China Medical Research Collaborative, School of Medicine, Cardiff University, Cardiff, CF14 4YS, UK
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Mehanna S, Issa MY, Hassan NH, Hussien AM, Ibrahim MA, Hassanen EI. Origanum majorana essential oil improves the rat’s sexual behavior and testicular oxidative damage induced by imidacloprid via modulating the steroidogenesis pathways. Saudi Pharm J 2022; 30:1315-1326. [PMID: 36249946 PMCID: PMC9563047 DOI: 10.1016/j.jsps.2022.06.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 06/17/2022] [Indexed: 10/24/2022] Open
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Guzmán-Ruiz MA, Jiménez A, Cárdenas-Rivera A, Guerrero-Vargas NN, Organista-Juárez D, Guevara-Guzmán R. Regulation of Metabolic Health by an "Olfactory-Hypothalamic Axis" and Its Possible Implications for the Development of Therapeutic Approaches for Obesity and T2D. Cell Mol Neurobiol 2021; 42:1727-1743. [PMID: 33813677 DOI: 10.1007/s10571-021-01080-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Accepted: 03/12/2021] [Indexed: 12/12/2022]
Abstract
The olfactory system is responsible for the reception, integration and interpretation of odors. However, in the last years, it has been discovered that the olfactory perception of food can rapidly modulate the activity of hypothalamic neurons involved in the regulation of energy balance. Conversely, the hormonal signals derived from changes in the metabolic status of the body can also change the sensitivity of the olfactory system, suggesting that the bidirectional relationship established between the olfactory and the hypothalamic systems is key for the maintenance of metabolic homeostasis. In the first part of this review, we describe the possible mechanisms and anatomical pathways involved in the modulation of energy balance regulated by the olfactory system. Hence, we propose a model to explain its implication in the maintenance of the metabolic homeostasis of the organism. In the second part, we discuss how the olfactory system could be involved in the development of metabolic diseases such as obesity and type two diabetes and, finally, we propose the use of intranasal therapies aimed to regulate and improve the activity of the olfactory system that in turn will be able to control the neuronal activity of hypothalamic centers to prevent or ameliorate metabolic diseases.
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Affiliation(s)
- Mara Alaide Guzmán-Ruiz
- Laboratorio Sensorial, Departamento de Fisiología, Facultad de Medicina, Edificio A, 4º piso, Universidad Nacional Autónoma de México (UNAM), 04510, Ciudad de México, México.
| | - Adriana Jiménez
- Laboratorio Sensorial, Departamento de Fisiología, Facultad de Medicina, Edificio A, 4º piso, Universidad Nacional Autónoma de México (UNAM), 04510, Ciudad de México, México
| | - Alfredo Cárdenas-Rivera
- Centro de Investigación en Bioingeniería, Universidad de Ingeniería y Tecnología, Lima, Perú
| | - Natalí N Guerrero-Vargas
- Departamento de Anatomía, Facultad de Medicina, Universidad Nacional Autónoma de México, México City, México
| | - Diana Organista-Juárez
- Laboratorio Sensorial, Departamento de Fisiología, Facultad de Medicina, Edificio A, 4º piso, Universidad Nacional Autónoma de México (UNAM), 04510, Ciudad de México, México
| | - Rosalinda Guevara-Guzmán
- Laboratorio Sensorial, Departamento de Fisiología, Facultad de Medicina, Edificio A, 4º piso, Universidad Nacional Autónoma de México (UNAM), 04510, Ciudad de México, México.
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Takahashi A, Sugimoto H, Kato S, Shiroishi T, Koide T. Mapping of Genetic Factors That Elicit Intermale Aggressive Behavior on Mouse Chromosome 15: Intruder Effects and the Complex Genetic Basis. PLoS One 2015; 10:e0137764. [PMID: 26389588 PMCID: PMC4577130 DOI: 10.1371/journal.pone.0137764] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 08/21/2015] [Indexed: 11/18/2022] Open
Abstract
Despite high estimates of the heritability of aggressiveness, the genetic basis for individual differences in aggression remains unclear. Previously, we showed that the wild-derived mouse strain MSM/Ms (MSM) exhibits highly aggressive behaviors, and identified chromosome 15 (Chr 15) as the location of one of the genetic factors behind this escalated aggression by using a panel of consomic strains of MSM in a C57BL/6J (B6) background. To understand the genetic effect of Chr 15 derived from MSM in detail, this study examined the aggressive behavior of a Chr 15 consomic strain towards different types of opponent. Our results showed that both resident and intruder animals had to have the same MSM Chr 15 genotype in order for attack bites to increase and attack latency to be reduced, whereas there was an intruder effect of MSM Chr 15 on tail rattle behavior. To narrow down the region that contains the genetic loci involved in the aggression-eliciting effects on Chr 15, we established a panel of subconsomic strains of MSM Chr 15. Analysis of these strains suggested the existence of multiple genes that enhance and suppress aggressive behavior on Chr 15, and these loci interact in a complex way. Regression analysis successfully identified four genetic loci on Chr 15 that influence attack latency, and one genetic locus that partially elicits aggressive behaviors was narrowed down to a 4.1-Mbp region (from 68.40 Mb to 72.50 Mb) on Chr 15.
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Affiliation(s)
- Aki Takahashi
- Mouse Genomics Resource Laboratory, National Institute of Genetics (NIG), Mishima, Shizuoka, Japan
- Department of Genetics, SOKENDAI, Mishima, Shizuoka, Japan
- Laboratory of Behavioral Neuroendocrinology, University of Tsukuba, Tsukuba, Ibaraki, Japan
- Transdisciplinary Research Integration Center, Research Organization of Information and Systems, Minato-ku, Tokyo, Japan
| | - Hiroki Sugimoto
- Mouse Genomics Resource Laboratory, National Institute of Genetics (NIG), Mishima, Shizuoka, Japan
- Division of Biology, Center for Molecular Medicine, Jichi Medical University, Shimotsuke, Tochigi, Japan
| | - Shogo Kato
- Transdisciplinary Research Integration Center, Research Organization of Information and Systems, Minato-ku, Tokyo, Japan
- The Institute of Statistical Mathematics, Tachikawa, Tokyo, Japan
| | - Toshihiko Shiroishi
- Department of Genetics, SOKENDAI, Mishima, Shizuoka, Japan
- Transdisciplinary Research Integration Center, Research Organization of Information and Systems, Minato-ku, Tokyo, Japan
- Mammalian Genetics Laboratory, NIG, Mishima, Shizuoka, Japan
| | - Tsuyoshi Koide
- Mouse Genomics Resource Laboratory, National Institute of Genetics (NIG), Mishima, Shizuoka, Japan
- Department of Genetics, SOKENDAI, Mishima, Shizuoka, Japan
- Transdisciplinary Research Integration Center, Research Organization of Information and Systems, Minato-ku, Tokyo, Japan
- * E-mail:
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Sheleg M, Yochum CL, Richardson JR, Wagner GC, Zhou R. Ephrin-A5 regulates inter-male aggression in mice. Behav Brain Res 2015; 286:300-7. [PMID: 25746458 DOI: 10.1016/j.bbr.2015.03.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Revised: 02/27/2015] [Accepted: 03/02/2015] [Indexed: 01/05/2023]
Abstract
The Eph family of receptor tyrosine kinases play key roles in both the patterning of the developing nervous system and neural plasticity in the mature brain. To determine functions of ephrin-A5, a GPI-linked ligand to the Eph receptors, in animal behavior regulations, we examined effects of its inactivation on male mouse aggression. When tested in the resident-intruder paradigm for offensive aggression, ephrin-A5-mutant animals (ephrin-A5(-/-)) exhibited severe reduction in conspecific aggression compared to wild-type controls. On the contrary, defensive aggression in the form of target biting was higher in ephrin-A5(-/-) mice, indicating that the mutant mice are capable of attacking behavior. In addition, given the critical role of olfaction in aggressive behavior, we examined the ability of the ephrin-A5(-/-) mice to smell and found no differences between the mutant and control animals. Testosterone levels in the mutant mice were also found to be within the normal range. Taken together, our data reveal a new role of ephrin-A5 in the regulation of aggressive behavior in mice.
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Affiliation(s)
- Michal Sheleg
- Departments of Chemical Biology, Susan Lehman-Cullman Laboratory for Cancer Research, Ernest Mario School of Pharmacy, Rutgers University, Piscataway, NJ 08854, USA
| | - Carrie L Yochum
- Environmental & Occupational Health Sciences Institute, UMDNJ/RWJMS, Piscataway, NJ 08854, USA
| | - Jason R Richardson
- Environmental & Occupational Health Sciences Institute, UMDNJ/RWJMS, Piscataway, NJ 08854, USA
| | - George C Wagner
- Environmental & Occupational Health Sciences Institute, UMDNJ/RWJMS, Piscataway, NJ 08854, USA; Department of Psychology, Rutgers University, New Brunswick, NJ 08854, USA.
| | - Renping Zhou
- Departments of Chemical Biology, Susan Lehman-Cullman Laboratory for Cancer Research, Ernest Mario School of Pharmacy, Rutgers University, Piscataway, NJ 08854, USA.
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Rao DB, Little PB, Sills R. Subsite awareness in neuropathology evaluation of National Toxicology Program (NTP) studies: a review of select neuroanatomical structures with their functional significance in rodents. Toxicol Pathol 2013; 42:487-509. [PMID: 24135464 PMCID: PMC3965620 DOI: 10.1177/0192623313501893] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
This review article is designed to serve as an introductory guide in neuroanatomy for toxicologic pathologists evaluating general toxicity studies. The article provides an overview of approximately 50 neuroanatomical subsites and their functional significance across 7 transverse sections of the brain. Also reviewed are 3 sections of the spinal cord, cranial and peripheral nerves (trigeminal and sciatic, respectively), and intestinal autonomic ganglia. The review is limited to the evaluation of hematoxylin and eosin-stained tissue sections, as light microscopic evaluation of these sections is an integral part of the first-tier toxicity screening of environmental chemicals, drugs, and other agents. Prominent neuroanatomical sites associated with major neurological disorders are noted. This guide, when used in conjunction with detailed neuroanatomic atlases, may aid in an understanding of the significance of functional neuroanatomy, thereby improving the characterization of neurotoxicity in general toxicity and safety evaluation studies.
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Affiliation(s)
- Deepa B. Rao
- Integrated Laboratory Systems, Inc., Research Triangle Park, North Carolina
| | - Peter B. Little
- Consultant, Experimental Pathology Laboratories, Inc., Research Triangle Park, North Carolina
| | - Robert Sills
- National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina
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Abstract
Aggressive behavior is observed in many animal species, such as insects, fish, lizards, frogs, and most mammals including humans. This wide range of conservation underscores the importance of aggressive behavior in the animals' survival and fitness, and the likely heritability of this behavior. Although typical patterns of aggressive behavior differ between species, there are several concordances in the neurobiology of aggression among rodents, primates, and humans. Studies with rodent models may eventually help us to understand the neurogenetic architecture of aggression in humans. However, it is important to recognize the difference between the ecological and ethological significance of aggressive behavior (species-typical aggression) and maladaptive violence (escalated aggression) when applying the findings of aggression research using animal models to human or veterinary medicine. Well-studied rodent models for aggressive behavior in the laboratory setting include the mouse (Mus musculus), rat (Rattus norvegicus), hamster (Mesocricetus auratus), and prairie vole (Microtus ochrogaster). The neural circuits of rodent aggression have been gradually elucidated by several techniques, e.g., immunohistochemistry of immediate-early gene (c-Fos) expression, intracranial drug microinjection, in vivo microdialysis, and optogenetics techniques. Also, evidence accumulated from the analysis of gene-knockout mice shows the involvement of several genes in aggression. Here, we review the brain circuits that have been implicated in aggression, such as the hypothalamus, prefrontal cortex (PFC), dorsal raphe nucleus (DRN), nucleus accumbens (NAc), and olfactory system. We then discuss the roles of glutamate and γ-aminobutyric acid (GABA), excitatory and inhibitory amino acids in the brain, as well as their receptors, in controlling aggressive behavior, focusing mainly on recent findings. At the end of this chapter, we discuss how genes can be identified that underlie individual differences in aggression, using the so-called forward genetics approach.
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Affiliation(s)
- Aki Takahashi
- Mouse Genomics Resource Laboratory, National Institute of Genetics, (NIG), 1111 Yata, Mishima, Shizuoka, 411-8540, Japan,
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Duportets L, Bozzolan F, Abrieux A, Maria A, Gadenne C, Debernard S. The transcription factor Krüppel homolog 1 is linked to the juvenile hormone-dependent maturation of sexual behavior in the male moth, Agrotis ipsilon. Gen Comp Endocrinol 2012; 176:158-66. [PMID: 22285394 DOI: 10.1016/j.ygcen.2012.01.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2011] [Revised: 01/04/2012] [Accepted: 01/07/2012] [Indexed: 12/26/2022]
Abstract
In the male moth, Agrotis ipsilon, the behavioral response and neuronal sensitivity in the primary olfactory center, the antennal lobe (AL), to sex pheromone increase with age and juvenile hormone (JH) biosynthesis. Although JH has been shown to control this age-dependent plasticity, the underlying signaling pathway remains obscure. In this context, we cloned a full cDNA encoding the Krüppel homolog 1 transcription factor (AipsKr-h1) of A. ipsilon, which was found to be predominantly expressed in ALs, where its amount increased concomitantly with age and sex pheromone responses. Conversely, the expression of AipsKr-h1 protein in the antenna was age-independent. Moreover, the administration of JH in immature males or fluvastatin, an inhibitor of JH biosynthesis, in mature males induced an increase or a decline of the AipsKr-h1 protein level in ALs, respectively. This effect was suppressed with a combined injection of fluvastatin and JH. Our results showed that Aipskr-h1 is a JH-upregulated gene that might mediate JH action on central pheromone processing, modulating sexual behavior in A. ipsilon.
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Affiliation(s)
- Line Duportets
- UMR 1272, UPMC-INRA, Physiologie de l'Insecte: Signalisation et Communication, Université Paris VI, Bâtiment A, 7 quai Saint Bernard, 75005 Paris, France
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Melloni RH, Ricci LA. Adolescent exposure to anabolic/androgenic steroids and the neurobiology of offensive aggression: a hypothalamic neural model based on findings in pubertal Syrian hamsters. Horm Behav 2010; 58:177-91. [PMID: 19914254 DOI: 10.1016/j.yhbeh.2009.11.002] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2009] [Revised: 11/04/2009] [Accepted: 11/05/2009] [Indexed: 01/12/2023]
Abstract
Considerable public attention has been focused on the issue of youth violence, particularly that associated with drug use. It is documented that anabolic steroid use by teenagers is associated with a higher incidence of aggressive behavior and serious violence, yet little is known about how these drugs produce the aggressive phenotype. Here we discuss work from our laboratory on the relationship between the development and activity of select neurotransmitter systems in the anterior hypothalamus and anabolic steroid-induced offensive aggression using pubertal male Syrian hamsters (Mesocricetus auratus) as an adolescent animal model, with the express goal of synthesizing these data into an cogent neural model of the developmental adaptations that may underlie anabolic steroid-induced aggressive behavior. Notably, alterations in each of the neural systems identified as important components of the anabolic steroid-induced aggressive response occurred in a sub-division of the anterior hypothalamic brain region we identified as the hamster equivalent of the latero-anterior hypothalamus, indicating that this sub-region of the hypothalamus is an important site of convergence for anabolic steroid-induced neural adaptations that precipitate offensive aggression. Based on these findings we present in this review a neural model to explain the neurochemical regulation of anabolic steroid-induced offensive aggression showing the hypothetical interaction between the arginine vasopressin, serotonin, dopamine, gamma-aminobutyric acid, and glutamate neural systems in the anterior hypothalamic brain region.
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Affiliation(s)
- Richard H Melloni
- Behavioral Neuroscience Program, Department of Psychology, 125 Nightingale Hall, Northeastern University, 360 Huntington Avenue, Boston, MA 02115, USA.
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Maruska KP, Fernald RD. Reproductive status regulates expression of sex steroid and GnRH receptors in the olfactory bulb. Behav Brain Res 2010; 213:208-17. [PMID: 20466023 DOI: 10.1016/j.bbr.2010.04.058] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2010] [Revised: 04/29/2010] [Accepted: 04/30/2010] [Indexed: 10/19/2022]
Abstract
Neuromodulators including gonadotropin-releasing hormone (GnRH) and sex steroids help integrate an animal's internal physiological state with incoming external cues, and can have profound effects on the processing of behaviorally relevant information, particularly from the olfactory system. While GnRH and steroid receptors are present in olfactory processing regions across vertebrates, little is known about whether their expression levels change with internal physiological state or external social cues. We used qRT-PCR to measure mRNA levels of two GnRH receptors (GnRH-R1, GnRH-R2), five sex steroid receptors (estrogen receptors: ERalpha, ERbetaa, ERbetab; androgen receptors: ARalpha, ARbeta), and aromatase in the olfactory bulb of the highly social African cichlid fish Astatotilapia burtoni. We asked whether these receptor levels changed with reproductive condition in females, or with social status, which regulates reproductive capacity in males. Our results reveal that mRNA levels of multiple sex steroid, GnRH receptor subtypes, and aromatase in the olfactory bulb vary with sex, social status in males, and reproductive condition in females, which highlights the potential importance of changing receptor levels in fine-tuning the olfactory system during the reproductive cycle. Further, steroid receptor mRNA levels were positively correlated with circulating steroid levels in males, but negatively correlated in females, suggesting different regulatory control between sexes. These results provide support for the hypothesis that the first-order olfactory relay station is a substrate for both GnRH and sex steroid modulation, and suggest that changes in receptor levels could be an important mechanism for regulating reproductive, social, and seasonal plasticity in olfactory perception observed across vertebrates.
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Affiliation(s)
- Karen P Maruska
- Biology Department, Stanford University, 371 Serra Mall, Stanford, CA 94305, USA.
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Mamiya PC, Hennesy Z, Zhou R, Wagner GC. Changes in attack behavior and activity in EphA5 knockout mice. Brain Res 2008; 1205:91-9. [PMID: 18353288 DOI: 10.1016/j.brainres.2008.02.047] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2007] [Revised: 02/14/2008] [Accepted: 02/17/2008] [Indexed: 11/21/2022]
Abstract
During development, Eph tyrosine kinase receptors and their ephrin ligands function as axon guidance molecules while, in adults, these molecules appear to be involved in the regulation of neural plasticity and emotion. The absence of EphA5 receptor mediated forward signaling may cause alterations in connectivity of neural networks and boundary formation during development, including central monoaminergic systems. In the present studies, we demonstrated altered aggressive responses by animals lacking functional EphA5 receptors. These behavioral changes were accompanied by altered concentrations of serotonin (5-HT) and the metabolite, 5-HIAA, in the hypothalamus. The changes of serotonin activity in hypothalamus also result in increase of body weight in EphA5 knockout mice. Furthermore, EphA5 knockout mice exhibited a significant decrease in activity levels following exposure to naïve intruders in their home cages. We conclude that the EphA5 receptor may be involved in mediation of aggressive behavior regulated, in part, by hypothalamic serotonin.
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Abstract
INTRODUCTION Anabolic androgenic steroids (AAS) affect human female sexual behaviors. Animal models have been useful in uncovering the neural mechanisms governing changes in female sexual response upon AAS exposure. AIM We quantify the sexual response of AAS-exposed gonadally intact female mice when paired with gonadally intact female or male pairs. METHODS C57Bl/6 female mice were systemically exposed to the AAS 17alpha-methyltestosterone (7.5 mg/kg) for 17 days via a subcutaneous osmotic implant. On days 15-17, these females were allowed to mate with males or proestrus female partners in familiar and unfamiliar testing arenas for 10 minutes. MAIN OUTCOME MEASURES The following behavioral responses were registered: parameters related to mounting behavior such as the frequency of mounts, attempts to mount, and the latency to the first mount, anogenital investigation, fights and escapes, rejections, pelvic thrusts, and lordotic responses. RESULTS We found that males displayed a significant decrease in the frequency of mounts to AAS-exposed females, when compared with mating encounters with control females. We found no difference in the lordosis strength when control females were mounted by either a male or AAS-exposed females. However, females under androgen exposure attempted to mount control females, but not males, and their behavior was accompanied by significant increases in the number of fights, escapes, and rejections to the male. There were no differences between AAS-exposed females and males when the frequency of mounts and pelvic thrusts toward control females were compared. The lordotic quotient of control females was similar for either partner. CONCLUSIONS Aside from showing a male-like pattern, AAS-exposed females displayed a higher frequency of anogenital investigations toward control females than males, and their latency to the first mount was as fast as that of males. Taken together, we conclude that the sex partner greatly influences the sexual response of AAS-exposed female mice.
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Hau M, Dominguez OA, Evrard HC. Testosterone reduces responsiveness to nociceptive stimuli in a wild bird. Horm Behav 2004; 46:165-70. [PMID: 15256306 DOI: 10.1016/j.yhbeh.2004.02.007] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2003] [Revised: 02/17/2004] [Accepted: 02/25/2004] [Indexed: 11/26/2022]
Abstract
The hormone testosterone (T) is involved in the control of aggressive behavior in male vertebrates. T enhances the frequency and intensity of aggressive behaviors during competitive interactions among males. By promoting high-intensity aggression, T also increases the risk of injury and presumably the perception of painful stimuli. However, perception of painful stimuli during fights could counteract the expression of further aggressive behavior. We therefore hypothesize that one function of T during aggressive interactions is to reduce nociception (pain sensitivity). Here, we experimentally document that T indeed reduces behavioral responsiveness to a thermal painful stimulus in captive male house sparrows (Passer domesticus). Skin nociception was quantified by foot immersion into a hot water bath, a benign thermal stimulus. Males treated with exogenous testosterone left their foot longer in hot water than control birds. Conversely, males in which the physiological actions of testosterone were pharmacologically blocked withdrew their foot faster than control birds. Testosterone might exert its effects on pain sensitivity through conversion into estradiol in the dorsal horn of the spinal cord. Decreased nociception during aggressive encounters may promote the immediate and future willingness of males to engage in high-intensity fights.
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Affiliation(s)
- Michaela Hau
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA.
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Evrard HC, Harada N, Balthazart J. Immunocytochemical localization of aromatase in sensory and integrating nuclei of the hindbrain in Japanese quail (Coturnix japonica). J Comp Neurol 2004; 473:194-212. [PMID: 15101089 DOI: 10.1002/cne.20068] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The distribution of the estrogen synthesizing enzyme (aromatase) in the hindbrain (rhombencephalon and mesencephalon) of male adult quail was investigated by immunocytochemistry. Aromatase-immunoreactive neuronal structures (perikarya and fibers bearing punctate structures) were observed in sensory (trigeminal, solitary tract, vestibular, optic tectum) and integrating (parabrachial, periaqueductal, cerulean, raphe) nuclei. Besides the expression of aromatase in these well-delineated nuclei, dense to scattered networks of immunoreactive fibers were found dispersed throughout the hindbrain and, in particular, in its rostral and dorsal parts. To a lesser extent, they were also present throughout the premotor nuclei of the reticular formation and in various fiber tracts. In contrast, no immunoreactive signal was found in motor nuclei, and in most of the statoacoustic (cerebellum, cochlear, olive, pontine, part of vestibular) nuclei. The expression of aromatase in perikarya and fibers in areas of the adult hindbrain where estrogen receptors have been identified previously suggests a role for estrogens locally produced in the regulation of sensory and integrating functions, contrary to the widespread assumption that these functions are regulated exclusively by steroids produced in the gonads.
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Affiliation(s)
- Henry C Evrard
- Center for Cellular and Molecular Neurobiology, Research Group in Behavioral Neuroendocrinology, University of Liège, B-4020 Liège, Belgium.
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Abstract
Anabolic-androgenic steroids (AAS) are synthetic derivatives of testosterone originally designed for therapeutic uses to provide enhanced anabolic potency with negligible androgenic effects. Although AAS continue to be used clinically today, the medical benefits of low therapeutic doses of AAS stand in sharp contrast to the potential health risks associated with the excessive doses self-administered not only by elite athletes and body builders, but by a growing number of recreational users, including adolescent boys and girls. The deleterious effects of AAS on peripheral organs and the incidence of altered behaviors in AAS abusers have been well documented in a number of excellent current reviews for clinical populations. However, a comparable synthesis of nonclinical studies has not been made. Our purpose in this review is to summarize the literature for animal models of the effects of supraphysiological doses of AAS (e.g. those that mimic human abuse regimes) on behaviors and on the neural circuitry for these behaviors. In particular, we have focused on studies in rodents that have examined how AAS alter aggression, sexual behaviors, anxiety, reward, learning, and locomotion and how AAS alter the expression and function of neurotransmitter systems and other signaling molecules that underlie these behaviors.
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Affiliation(s)
- Ann S Clark
- Department of Psychological and Brain Sciences, Dartmouth College, 6207 Moore Hall, Hanover, NH 03755, USA.
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Abstract
In rodents, where chemical signals play a particularly important role in determining intersexual interactions, various studies have shown that male behavior and physiology is sensitive to female odor cues. Here we examined the effects of brief (1 min) and more prolonged (60 min) preexposure to the odors of a novel estrous female on the behavioral and hormonal responses of sexually experienced and inexperienced male mice, Mus musculus, to subsequent predator (cat and weasel) odor exposure and potential predator risk. Brief, but not prolonged, preexposure to the odors of an estrous female decreased the aversion and avoidance responses of male mice to cat odor in a Y-maze preference test, with the extent of responses being affected by a males prior sexual experience. Similarly, brief, but not prolonged, preexposure to female odors markedly attenuated the analgesic responses elicited in male mice by weasel odor. Brief exposure to a novel estrous female by itself had no significant immediate effects on either corticosterone or testosterone levels in the males. However, brief, but not prolonged, preexposure to the odors of an estrous female attenuated the marked increase in corticosterone and decrease in testosterone that were induced in males by exposure to weasel odor. The decreases in aversive responses to, and effects of, predator odor exposure that are induced by brief exposure to a novel estrous female may reflect a greater risk taking and boldness in males that could directly facilitate access to an immediately, and possibly transiently, available novel sexually receptive female.
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Affiliation(s)
- M Kavaliers
- Department of Psychology, University of Western Ontario, London, Ontario, N6A 5C2, Canada.
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Halem HA, Baum MJ, Cherry JA. Sex difference and steroid modulation of pheromone-induced immediate early genes in the two zones of the mouse accessory olfactory system. J Neurosci 2001; 21:2474-80. [PMID: 11264321 [PMID: 11264321 DOI: 10.1523/jneurosci.21-07-02474.2001] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Two anatomically and neurochemically distinct zones within the vomeronasal organ (VNO) and accessory olfactory bulb (AOB) have been identified that are responsible for the detection of pheromones. Using markers to distinguish between apical and basal neurons of the VNO neuroepithelium and rostral versus caudal AOB glomeruli, we examined immediate early gene immunoreactivity (IEG-IR) in gonadectomized, steroid-treated mice in response to pheromones of male and female conspecifics. After exposure of estradiol-treated females to soiled male bedding, more VNO neurons in the basal than the apical layer exhibited IEG-IR compared with VNO neurons of estradiol-treated males. Conversely, whereas soiled female bedding failed to induce IEG-IR in VNO neurons of estradiol-treated males or females, both apical and basal neurons were activated in testosterone-treated males. Male and female pheromones also activated mitral and granule cells in the AOBs of all subjects, but responses to different pheromones were distributed across the boundary of the rostral and caudal regions. These data show that differences in the response of males and females to the same pheromonal stimulus are found in the sensory neurons of the VNO. We propose that centrifugal, noradrenergic inputs to VNO neurons, which may differ in the two sexes and respond differently to adult sex steroids, modulate sensitivity to pheromonal stimulation.
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Abstract
The capacity to attack a passive standard opponent in a resident-intruder test and the GAD activity in the olfactory bulbs were measured in 140 male mice from seven different inbred mouse strains. The effect of the non-pseudo autosomal region of the Y-chromosome (YNPAR) on these two phenotypes has also been investigated using a quartet of reciprocal strains congenic for the YNPAR. A strong negative correlation was found between the two variables but the YNPAR is not involved. This result suggests that males of more attacking strains have a lower olfactory threshold, making the olfactory discrimination of the opponent easier and its identification as a stranger more efficient.
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Affiliation(s)
- P V Guillot
- Mammalian Genetics Unit, Medical Research Council, Harwell, Didcot, Oxfordshire, UK.
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