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Kobayashi-Sakashita M, Kiyokawa Y, Takeuchi Y. Parallel Olfactory Systems Synergistically Activate the Posteroventral Part of the Medial Amygdala Upon Alarm Pheromone Detection in Rats. Neuroscience 2023; 521:123-133. [PMID: 37121380 DOI: 10.1016/j.neuroscience.2023.04.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 03/27/2023] [Accepted: 04/24/2023] [Indexed: 05/02/2023]
Abstract
In rats, a mixture of hexanal and 4-methylpentanal is a main component of the alarm pheromone. When detected by the main olfactory system (MOS) and the vomeronasal system, respectively, they activate the anterior part of the bed nucleus of the stria terminalis (BNSTa). Therefore, the information from the two olfactory systems is expected to be integrated before being transmitted to the BNSTa. To specify the integration site, we examined Fos expression in 16 brain regions in response to water (n = 10), hexanal (n = 9), 4-methylpentanal (n = 9), the mixture (n = 9), or the alarm pheromone (n = 9) in male rats. The posteroventral part of the medial amygdala showed increased Fos expression to hexanal and 4-methylpentanal. The expression was further increased by the mixture. Therefore, this region is suggested as the integration site. In addition, the BNSTa, paraventricular nucleus of the hypothalamus, and anteroventral, anterodorsal, and posterodorsal parts of the medial amygdala were suggested to be located downstream of the integrated site because only the mixture increased Fos expression. We suggest that the posterolateral part of the cortical amygdala is upstream of the integration site in the MOS because all stimuli increased Fos expression. The posterior part of the bed nucleus of the stria terminalis and posteromedial part of the cortical amygdala were suggested as being located upstream in the vomeronasal system because 4-methylpentanal and the mixture increased Fos expression. These results provide information about the neural pathway underlying the alarm pheromone effects.
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Affiliation(s)
- Mao Kobayashi-Sakashita
- Laboratory of Veterinary Ethology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Yasushi Kiyokawa
- Laboratory of Veterinary Ethology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
| | - Yukari Takeuchi
- Laboratory of Veterinary Ethology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
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2
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Zhao X, Castelli FR, Wang R, Auger AP, Marler CA. Testosterone-related behavioral and neural mechanisms associated with location preferences: A model for territorial establishment. Horm Behav 2020; 121:104709. [PMID: 32007517 DOI: 10.1016/j.yhbeh.2020.104709] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 01/27/2020] [Accepted: 01/28/2020] [Indexed: 11/21/2022]
Abstract
Territoriality is an adaptive behavioral trait that is important for animal's fitness and there still remains much to learn about the proximate mechanisms underlying the development of territoriality. We speculate that the formation of a conditioned place preference (CPP), an increased time allocation to the environment where a rewarding experience occurred, contributes to territoriality. Testosterone (T) plays an important role in modulating territorial behaviors and T pulses can induce a CPP. We confirmed previous findings in California mice (Peromyscus californicus) that T pulses can induce a CPP in singly-housed, but not group-housed males. Housing singly may be similar enough to dispersal in nature to initiate similar hormonal and neuroanatomical changes needed for the development of territoriality. We further revealed that T pulses interact with the single housing experience and appear to enhance the motivation to be aggressive towards a stimulus male. On a neural level, being singly housed upregulated levels of androgen receptors in the preoptic area, which positively correlated with the strength of the CPP. We speculate that this change in androgen sensitivity in the preoptic area is characteristic of males that have dispersed, making them more sensitive to T pulses. Also, single housing increased markers of synaptic plasticity in the nucleus accumbens, ventral and dorsal hippocampus, neural changes that may be associated with dispersal, reproduction and territory establishment. These behavioral and neural changes may reflect the life history transition from residing in the natal territory to dispersing and establishing a new territory.
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Affiliation(s)
- Xin Zhao
- Department of Psychology, University of Wisconsin, Madison, WI 53706, USA.
| | - Frank R Castelli
- Department of Psychology, University of Wisconsin, Madison, WI 53706, USA
| | - Ruyi Wang
- Department of Psychology, University of Wisconsin, Madison, WI 53706, USA
| | - Anthony P Auger
- Department of Psychology, University of Wisconsin, Madison, WI 53706, USA
| | - Catherine A Marler
- Department of Psychology, University of Wisconsin, Madison, WI 53706, USA
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Central role of G protein Gαi2 and Gαi2 + vomeronasal neurons in balancing territorial and infant-directed aggression of male mice. Proc Natl Acad Sci U S A 2019; 116:5135-5143. [PMID: 30804203 DOI: 10.1073/pnas.1821492116] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Aggression is controlled by the olfactory system in many animal species. In male mice, territorial and infant-directed aggression are tightly regulated by the vomeronasal organ (VNO), but how diverse subsets of sensory neurons convey pheromonal information to limbic centers is not yet known. Here, we employ genetic strategies to show that mouse vomeronasal sensory neurons expressing the G protein subunit Gαi2 regulate male-male and infant-directed aggression through distinct circuit mechanisms. Conditional ablation of Gαi2 enhances male-male aggression and increases neural activity in the medial amygdala (MeA), bed nucleus of the stria terminalis, and lateral septum. By contrast, conditional Gαi2 ablation causes reduced infant-directed aggression and decreased activity in MeA neurons during male-infant interactions. Strikingly, these mice also display enhanced parental behavior and elevated neural activity in the medial preoptic area, whereas sexual behavior remains normal. These results identify Gαi2 as the primary G protein α-subunit mediating the detection of volatile chemosignals in the apical layer of the VNO, and they show that Gαi2+ VSNs and the brain circuits activated by these neurons play a central role in orchestrating and balancing territorial and infant-directed aggression of male mice through bidirectional activation and inhibition of different targets in the limbic system.
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Zancan M, Cunha RSR, Schroeder F, Xavier LL, Rasia‐Filho AA. Remodeling of the number and structure of dendritic spines in the medial amygdala: From prepubertal sexual dimorphism to puberty and effect of sexual experience in male rats. Eur J Neurosci 2018; 48:1851-1865. [DOI: 10.1111/ejn.14052] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 04/18/2018] [Accepted: 06/13/2018] [Indexed: 12/21/2022]
Affiliation(s)
- Mariana Zancan
- Department of Basic Sciences/PhysiologyFederal University of Health Sciences Porto Alegre Brazil
- Graduation Program in NeuroscienceFederal University of Rio Grande do Sul Porto Alegre Brazil
| | - Rick Shandler R. Cunha
- Department of Basic Sciences/PhysiologyFederal University of Health Sciences Porto Alegre Brazil
| | - Francielle Schroeder
- Laboratory of Tissue BiologyFaculty of BiosciencesPontifical Catholic University of Rio Grande do Sul (PUCRS) Porto Alegre Brazil
| | - Léder L. Xavier
- Laboratory of Tissue BiologyFaculty of BiosciencesPontifical Catholic University of Rio Grande do Sul (PUCRS) Porto Alegre Brazil
| | - Alberto A. Rasia‐Filho
- Department of Basic Sciences/PhysiologyFederal University of Health Sciences Porto Alegre Brazil
- Graduation Program in NeuroscienceFederal University of Rio Grande do Sul Porto Alegre Brazil
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Frankiensztajn LM, Gur-Pollack R, Wagner S. A combinatorial modulation of synaptic plasticity in the rat medial amygdala by oxytocin, urocortin3 and estrogen. Psychoneuroendocrinology 2018; 92:95-102. [PMID: 29674171 DOI: 10.1016/j.psyneuen.2018.04.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 04/07/2018] [Accepted: 04/09/2018] [Indexed: 12/14/2022]
Abstract
The medial nucleus of the amygdala (MeA) plays a pivotal role in a variety of mammalian social behaviors. Specifically, activity of the hypothalamic pro-social neuropeptide oxytocin in the MeA was shown to be crucial for social recognition memory. The MeA is also a hub of neuroendocrine activity and expresses a large number of receptors of neuropeptides and hormones. These include oxytocin receptor, estrogen receptor alpha and corticotropin-releasing factor (CRF) receptor type 2 (CRFR2). In a previous study we found that intracerebroventricular (ICV) oxytocin application to anesthetized rats promotes long-term depression (LTD) of the MeA response to electrical stimulation of its main sensory input, the accessory olfactory bulb (AOB). We also reported that this type of synaptic plasticity contributes to long-term social recognition memory. Here we used similar methodology to examine the possibility that various neuromodulators pose a combinatorial effect on synaptic plasticity in the MeA. We found that ICV administration of the CRF-related peptide urocortin3 fifteen minutes before oxytocin, caused long-term potentiation (LTP), via CRFR2 activation. Similarly, ICV administration of 17β-estradiol forty-five minutes before oxytocin induced LTP, which was blocked by an antagonist of the estrogen receptors alpha and beta. Notably, none of these two neuromodulators had any effect on its own, suggesting that they both turn the oxytocin-mediated synaptic plasticity from LTD to LTP. Finally, we found that application of 17β-estradiol, forty-five minutes before urocortin3 also caused LTP in the MeA response to AOB stimulation, even without oxytocin application. We suggest that the combinatorial modulation of the bidirectional synaptic plasticity in the AOB-MeA pathway by oxytocin, 17β-estradiol and urocotin-3 serves to modify social information processing according to the animal's internal state.
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Affiliation(s)
- Linoy Mia Frankiensztajn
- Sagol Department of Neurobiology, The Integrated Brain and Behavior Research Center (IBBR), University of Haifa, Haifa 3498838, Israel
| | - Rotem Gur-Pollack
- Sagol Department of Neurobiology, The Integrated Brain and Behavior Research Center (IBBR), University of Haifa, Haifa 3498838, Israel
| | - Shlomo Wagner
- Sagol Department of Neurobiology, The Integrated Brain and Behavior Research Center (IBBR), University of Haifa, Haifa 3498838, Israel.
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Adekunbi DA, Li XF, Lass G, Shetty K, Adegoke OA, Yeo SH, Colledge WH, Lightman SL, O'Byrne KT. Kisspeptin neurones in the posterodorsal medial amygdala modulate sexual partner preference and anxiety in male mice. J Neuroendocrinol 2018; 30:e12572. [PMID: 29356147 PMCID: PMC5873280 DOI: 10.1111/jne.12572] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 01/05/2018] [Accepted: 01/16/2018] [Indexed: 01/27/2023]
Abstract
The posterodorsal medial amygdala (MePD) is a neural site in the limbic brain involved in regulating emotional and sexual behaviours. There is, however, limited information available on the specific neuronal cell type in the MePD functionally mediating these behaviours in rodents. The recent discovery of a significant kisspeptin neurone population in the MePD has raised interest in the possible role of kisspeptin and its cognate receptor in sexual behaviour. The present study therefore tested the hypothesis that the MePD kisspeptin neurone population is involved in regulating attraction towards opposite sex conspecifics, sexual behaviour, social interaction and the anxiety response by selectively stimulating these neurones using the novel pharmacosynthetic DREADDs (designer receptors exclusively activated by designer drugs) technique. Adult male Kiss-Cre mice received bilateral stereotaxic injections of a stimulatory DREADD viral construct (AAV-hSyn-DIO-hM3 D(Gq)-mCherry) targeted to the MePD, with subsequent activation by i.p. injection of clozapine-N-oxide (CNO). Socio-sexual behaviours were assessed in a counter-balanced fashion after i.p. injection of either saline or CNO (5 mg kg-1 ). Selective activation of MePD kisspeptin neurones by CNO significantly increased the time spent by male mice in investigating an oestrous female, as well as the duration of social interaction. Additionally, after CNO injection, the mice appeared less anxious, as indicated by a longer exploratory time in the open arms of the elevated plus maze. However, levels of copulatory behaviour were comparable between CNO and saline-treated controls. These data indicate that DREADD-induced activation of MePD kisspeptin neurones enhances both sexual partner preference in males and social interaction and also decreases anxiety, suggesting a key role played by MePD kisspeptin in sexual motivation and social behaviour.
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Affiliation(s)
- D. A. Adekunbi
- Division of Women's HealthFaculty of Life Sciences and MedicineKing's College LondonLondonUK
- Department of PhysiologyCollege of MedicineUniversity of LagosLagosNigeria
| | - X. F. Li
- Division of Women's HealthFaculty of Life Sciences and MedicineKing's College LondonLondonUK
| | - G. Lass
- Division of Women's HealthFaculty of Life Sciences and MedicineKing's College LondonLondonUK
| | - K. Shetty
- Division of Women's HealthFaculty of Life Sciences and MedicineKing's College LondonLondonUK
| | - O. A. Adegoke
- Department of PhysiologyCollege of MedicineUniversity of LagosLagosNigeria
| | - S. H. Yeo
- Reproductive Physiology GroupDepartment of Physiology, Development and NeuroscienceUniversity of CambridgeCambridgeUK
| | - W. H. Colledge
- Reproductive Physiology GroupDepartment of Physiology, Development and NeuroscienceUniversity of CambridgeCambridgeUK
| | - S. L. Lightman
- Henry Wellcome Laboratory for Integrative Neuroscience and EndocrinologyUniversity of BristolBristolUK
| | - K. T. O'Byrne
- Division of Women's HealthFaculty of Life Sciences and MedicineKing's College LondonLondonUK
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Zancan M, Dall'Oglio A, Quagliotto E, Rasia‐Filho AA. Castration alters the number and structure of dendritic spines in the male posterodorsal medial amygdala. Eur J Neurosci 2016; 45:572-580. [DOI: 10.1111/ejn.13460] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 10/22/2016] [Accepted: 10/31/2016] [Indexed: 01/21/2023]
Affiliation(s)
- Mariana Zancan
- Department of Basic Sciences/Physiology Federal University of Health Sciences Sarmento Leite 245 Porto Alegre RS 90050‐170 Brazil
- Graduation Program in Neuroscience Federal University of Rio Grande do Sul Porto Alegre Brazil
| | - Aline Dall'Oglio
- Department of Basic Sciences/Physiology Federal University of Health Sciences Sarmento Leite 245 Porto Alegre RS 90050‐170 Brazil
| | - Edson Quagliotto
- Department of Basic Sciences/Physiology Federal University of Health Sciences Sarmento Leite 245 Porto Alegre RS 90050‐170 Brazil
| | - Alberto A. Rasia‐Filho
- Department of Basic Sciences/Physiology Federal University of Health Sciences Sarmento Leite 245 Porto Alegre RS 90050‐170 Brazil
- Graduation Program in Neuroscience Federal University of Rio Grande do Sul Porto Alegre Brazil
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8
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Clinard CT, Barnes AK, Adler SG, Cooper MA. Winning agonistic encounters increases testosterone and androgen receptor expression in Syrian hamsters. Horm Behav 2016; 86:27-35. [PMID: 27619945 PMCID: PMC5159211 DOI: 10.1016/j.yhbeh.2016.09.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Revised: 06/30/2016] [Accepted: 09/08/2016] [Indexed: 11/16/2022]
Abstract
Winning aggressive disputes is one of several experiences that can alter responses to future stressful events. We have previously tested dominant and subordinate male Syrian hamsters in a conditioned defeat model and found that dominant individuals show less change in behavior following social defeat stress compared to subordinates and controls, indicating a reduced conditioned defeat response. Resistance to the effects of social defeat in dominants is experience-dependent and requires the maintenance of dominance relationships for 14days. For this study we investigated whether winning aggressive interactions increases plasma testosterone and whether repeatedly winning increases androgen receptor expression. First, male hamsters were paired in daily 10-min aggressive encounters and blood samples were collected immediately before and 15min and 30min after the formation of dominance relationships. Dominants showed an increase in plasma testosterone at 15min post-interaction compared to their pre-interaction baseline, whereas subordinates and controls showed no change in plasma testosterone. Secondly, we investigated whether 14days of dominant social status increased androgen or estrogen alpha-receptor immunoreactivity in brain regions that regulate the conditioned defeat response. Dominants showed more androgen, but not estrogen alpha, receptor immuno-positive cells in the dorsal medial amygdala (dMeA) and ventral lateral septum (vLS) compared to subordinates and controls. Finally, we showed that one day of dominant social status was insufficient to increase androgen receptor immunoreactivity compared to subordinates. These results suggest that elevated testosterone signaling at androgen receptors in the dMeA and vLS might contribute to the reduced conditioned defeat response exhibited by dominant hamsters.
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Affiliation(s)
- Catherine T Clinard
- Department of Psychology, University of Tennessee, Knoxville, TN 37996, United States.
| | - Abigail K Barnes
- Department of Psychology, University of Tennessee, Knoxville, TN 37996, United States
| | - Samuel G Adler
- Department of Psychology, University of Tennessee, Knoxville, TN 37996, United States
| | - Matthew A Cooper
- Department of Psychology, University of Tennessee, Knoxville, TN 37996, United States
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Job MO, Cooke BM. PSA-NCAM in the posterodorsal medial amygdala is necessary for the pubertal emergence of attraction to female odors in male hamsters. Horm Behav 2015; 75:91-9. [PMID: 26335887 DOI: 10.1016/j.yhbeh.2015.08.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 08/19/2015] [Accepted: 08/22/2015] [Indexed: 10/23/2022]
Abstract
During puberty, attention turns away from same-sex socialization to focus on the opposite sex. How the brain mediates this change in perception and motivation is unknown. Polysialylated neural cell adhesion molecule (PSA-NCAM) virtually disappears from most of the central nervous system after embryogenesis, but it remains elevated in discrete regions of the adult brain. One such brain area is the posterodorsal subnucleus of the medial amygdala (MePD). The MePD has been implicated in male sexual attraction, measured here as the preference to investigate female odors. We hypothesize that PSA-NCAM gates hormone-dependent plasticity necessary for the emergence of males' attraction to females. To evaluate this idea, we first measured PSA-NCAM levels across puberty in several brain regions, and identified when female odor preference normally emerges in male Syrian hamsters. We found that MePD PSA-NCAM staining peaks shortly before the surge of pubertal androgen and the emergence of preference. To test the necessity of PSA-NCAM for female odor preference, we infused endo-neuraminidase-N into the MePD to deplete it of PSAs before female odor preference normally appears. This blocked female odor preference, which suggests that PSA-NCAM facilitates behaviorally relevant, hormone-driven plasticity.
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Affiliation(s)
- Martin O Job
- Neuroscience Institute, Georgia State University, Atlanta, GA 30303, USA
| | - Bradley M Cooke
- Neuroscience Institute, Georgia State University, Atlanta, GA 30303, USA.
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Benesh EC, Gill J, Lamb LE, Moley KH. Maternal Obesity, Cage Density, and Age Contribute to Prostate Hyperplasia in Mice. Reprod Sci 2015; 23:176-85. [PMID: 26243546 DOI: 10.1177/1933719115597767] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Identification of modifiable risk factors is gravely needed to prevent adverse prostate health outcomes. We previously developed a murine precancer model in which exposure to maternal obesity stimulated prostate hyperplasia in offspring. Here, we used generalized linear modeling to evaluate the influence of additional environmental covariates on prostate hyperplasia. As expected from our previous work, the model revealed that aging and maternal diet-induced obesity (DIO) each correlated with prostate hyperplasia. However, prostate hyperplasia was not correlated with the length of maternal DIO. Cage density positively associated with both prostate hyperplasia and offspring body weight. Expression of the glucocorticoid receptor in prostates also positively correlated with cage density and negatively correlated with age of the animal. Together, these findings suggest that prostate tissue was adversely patterned during early life by maternal overnutrition and was susceptible to alteration by environmental factors such as cage density. Additionally, prostate hyperplasia may be acutely influenced by exposure to DIO, rather than occurring as a response to worsening obesity and comorbidities experienced by the mother. Finally, cage density correlated with both corticosteroid receptor abundance and prostate hyperplasia, suggesting that overcrowding influenced offspring prostate hyperplasia. These results emphasize the need for multivariate regression models to evaluate the influence of coordinated variables in complicated animal systems.
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Affiliation(s)
- Emily C Benesh
- Department of Obstetrics and Gynecology, Washington University in St Louis, School of Medicine, St Louis, MO, USA
| | - Jeff Gill
- Division of Public Health Sciences, Department of Surgery, Washington University in St Louis, School of Medicine, St Louis, MO, USA Division of Biostatistics, Washington University in St Louis, School of Medicine, St Louis, MO, USA Department of Political Science, Washington University in St Louis, One Brookings Dr, St Louis, MO, USA
| | - Laura E Lamb
- Beaumont Health Systems Research Institute, Royal Oak, MI
| | - Kelle H Moley
- Department of Obstetrics and Gynecology, Washington University in St Louis, School of Medicine, St Louis, MO, USA
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Zancan M, Dall'Oglio A, Sarzenski TM, Maher MI, Garcia-Segura LM, Rasia-Filho AA. Glial and axonal perikaryal coverage and somatic spines in the posterodorsal medial amygdala of male and cycling female rats. J Comp Neurol 2015; 523:2127-37. [DOI: 10.1002/cne.23782] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2014] [Revised: 03/24/2015] [Accepted: 03/26/2015] [Indexed: 12/29/2022]
Affiliation(s)
- Mariana Zancan
- DCBS-Physiology, Federal University of Health Sciences; Porto Alegre, Rio Grande do Sul 90050-110 Brazil
| | - Aline Dall'Oglio
- DCBS-Physiology, Federal University of Health Sciences; Porto Alegre, Rio Grande do Sul 90050-110 Brazil
| | - Taís Malysz Sarzenski
- ICBS-Anatomy, Federal University of Rio Grande do Sul; Porto Alegre, Rio Grande do Sul 90050-110 Brazil
| | - Martin Ian Maher
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC); 28002 Madrid Spain
| | | | - Alberto A. Rasia-Filho
- DCBS-Physiology, Federal University of Health Sciences; Porto Alegre, Rio Grande do Sul 90050-110 Brazil
- Graduation Program in Neurosciences, Federal University of Rio Grande do Sul; Porto Alegre, Rio Grande do Sul 90050-110 Brazil
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Hari Dass SA, Vyas A. Toxoplasma gondii infection reduces predator aversion in rats through epigenetic modulation in the host medial amygdala. Mol Ecol 2014; 23:6114-22. [PMID: 25142402 DOI: 10.1111/mec.12888] [Citation(s) in RCA: 97] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Revised: 08/02/2014] [Accepted: 08/06/2014] [Indexed: 12/14/2022]
Abstract
Male rats (Rattus novergicus) infected with protozoan Toxoplasma gondii relinquish their innate aversion to the cat odours. This behavioural change is postulated to increase transmission of the parasite to its definitive felid hosts. Here, we show that the Toxoplasma gondii infection institutes an epigenetic change in the DNA methylation of the arginine vasopressin promoter in the medial amygdala of male rats. Infected animals exhibit hypomethylation of arginine vasopressin promoter, leading to greater expression of this nonapeptide. The infection also results in the greater activation of the vasopressinergic neurons after exposure to the cat odour. Furthermore, we show that loss of fear in the infected animals can be rescued by the systemic hypermethylation and recapitulated by directed hypomethylation in the medial amygdala. These results demonstrate an epigenetic proximate mechanism underlying the extended phenotype in the Rattus novergicus-Toxoplasma gondii association.
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13
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Hari Dass SA, Vyas A. Copulation or sensory cues from the female augment Fos expression in arginine vasopressin neurons of the posterodorsal medial amygdala of male rats. Front Zool 2014; 11:42. [PMID: 24926317 PMCID: PMC4054915 DOI: 10.1186/1742-9994-11-42] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2014] [Accepted: 05/22/2014] [Indexed: 11/13/2022] Open
Abstract
Background The posterodorsal part of the medial amygdala is essential for processing reproductively salient sensory information in rodents. This is the initial brain structure where information from olfactory system and male hormones intersect. The neurochemical identity of the neurons participating in the sensory processing in medial amygdala remains presently undetermined. Many neurons in this brain structure express arginine vasopressin in a testosterone-dependent manner, suggesting that this neuropeptide is maintained by the androgenic milieu. Method Here we use Fos, a protein expressed by recently active neurons, to quantify activation of arginine vasopressin neurons after exposure to odor from physically inaccessible female. We compare it to mating with accessible female and to reproductively innocuous odor. Results We show that inaccessible female activate arginine vasopressin neurons in the male posterodorsal medial amygdala. The magnitude of activation is not further enhanced when physical access with resultant mating is granted, even though it remains undetermined if same population of AVP neurons is activated by both inaccessible female and copulation. We also show that arginine vasopressin activation cannot be fully accounted for by mere increase in the number of Fos and AVP neurons. Conclusion These observations posit a role for the medial amygdala arginine vasopressin in reproductive behaviors, suggesting that these neurons serve as integrative node between the hormonal status of the animal and the availability of reproductive opportunities.
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Affiliation(s)
- Shantala Arundathi Hari Dass
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Nanyang 637551, Republic of Singapore
| | - Ajai Vyas
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Nanyang 637551, Republic of Singapore
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Veening J, Coolen L. Neural mechanisms of sexual behavior in the male rat: Emphasis on ejaculation-related circuits. Pharmacol Biochem Behav 2014; 121:170-83. [DOI: 10.1016/j.pbb.2013.12.017] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Revised: 12/12/2013] [Accepted: 12/16/2013] [Indexed: 01/20/2023]
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15
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Maintenance of dominance status is necessary for resistance to social defeat stress in Syrian hamsters. Behav Brain Res 2014; 270:277-86. [PMID: 24875769 DOI: 10.1016/j.bbr.2014.05.041] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Revised: 05/16/2014] [Accepted: 05/19/2014] [Indexed: 01/15/2023]
Abstract
Resilience is an active process that involves a discrete set of neural substrates and cellular mechanisms and enables individuals to avoid some of the negative consequences of extreme stress. We have previously shown that dominant individuals show less stress-induced changes in behavior compared to subordinates using a conditioned defeat model in male Syrian hamsters (Mesocricetus auratus). To rule out pre-existing differences between dominants and subordinates, we examined whether 14 days of dominance experience is required to reduce the conditioned defeat response and whether the development of conditioned defeat resistance correlates with defeat-induced neural activation in select brain regions. We paired hamsters in daily 5-min aggressive encounters for 1, 7, or 14 days and then exposed animals to 3, 5-min social defeat episodes. The next day animals received conditioned defeat testing which involved a 5-min social interaction test with a non-aggressive intruder. In separate animals brains were collected after social defeat for c-Fos immunohistochemistry. We found that 14-day dominants showed a decreased conditioned defeat response compared to 14-day subordinates and controls, while 1-day and 7-day dominants did not differ from their subordinate counterparts. Also, the duration of dominance relationship was associated with distinct patterns of defeat-induced neural activation such that only 14-day dominants showed elevated c-Fos immunoreactivity in the ventral medial prefrontal cortex, medial amygdala, and lateral portions of the ventral medial hypothalamus. Our data suggest that resistance to social stress develops during the maintenance of dominance relationships and is associated with experience-dependent neural plasticity in select brain regions.
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Holmes MM, Van Mil S, Bulkowski C, Goldman SL, Goldman BD, Forger NG. Androgen receptor distribution in the social decision-making network of eusocial naked mole-rats. Behav Brain Res 2013; 256:214-8. [DOI: 10.1016/j.bbr.2013.08.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2013] [Revised: 08/13/2013] [Accepted: 08/15/2013] [Indexed: 10/26/2022]
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He F, Wu R, Yu P. Study of Fos, androgen receptor and testosterone expression in the sub-regions of medial amygdala, bed nucleus of stria terminalis and medial preoptic area in male Mandarin voles in response to chemosensory stimulation. Behav Brain Res 2013; 258:65-74. [PMID: 24129216 DOI: 10.1016/j.bbr.2013.10.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 10/02/2013] [Accepted: 10/05/2013] [Indexed: 11/28/2022]
Abstract
In many rodent species, including mandarin voles (Microtus mandarinus), the behavioral response to odors is regulated by a network of steroid-sensitive ventral forebrain nuclei including the medial amygdala (Me), bed nucleus of the striaterminalis (BNST), and medial preoptic area (MPOA). Although it is well-known that Me, BNST, and MPOA are closely interconnected, function independently in regulating odor-guided social behaviors, little is known about how order information is processed in the sub-regions of Me, BNST, and MPOA. In order to answer this question, we let male mandarin voles expose to two different odors including female vaginal fluid (FVF) and male flank gland secretion (MFGS) and detect the expression of Fos, androgen receptor (AR) and testosterone (T) in the sub-regions of Me, BNST, and MPOA. We found that FVF stimulus caused increased Fos, AR and T expression in the posterior subdivision of the Me (MeP), the posterior medial subdivision of the BNST (BNSTpm), and the medial preoptic nucleus (MPN), while MFGS stimulus did not change Fos, AR and T expression neither in the MeP, BNSTpm, and MPN nor in the anterior subdivision of the Me (MeA), the posterointermediate subdivision of the BNST (BNSTpi), and the lateral subdivision of the MPOA (MPOAl). Serum testosterone levels were increased after 1h in males exposed to FVF. This study provides insight in understanding the relationship between female odor stimulation and Fos, AR and T expression in specific brain areas in males, and the regulatory role of testosterone in this biochemical process.
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Affiliation(s)
- Fengqin He
- Institute of Brain and Behavioral Sciences, College of Biotechnology, Xi'an University of Arts and Science, Xi'an 710065, China.
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