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Corre PHC, Mainwaring JM, Peralta KKZ, Lokman PM, Porteous R, Wibowo E. Low dose of propyl-pyrazole-triol, an agonist of estrogen receptor alpha, administration stimulates the Coolidge effect in fadrozole-treated male rats. Horm Behav 2024; 161:105520. [PMID: 38447331 DOI: 10.1016/j.yhbeh.2024.105520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 02/22/2024] [Accepted: 02/23/2024] [Indexed: 03/08/2024]
Abstract
Estrogen receptor (ER) α is involved in male sexual function. Here, we aim to investigate how ERα activation influences sexual satiety and the Coolidge effect (i.e., when a rat, that has reached sexual satiety, experiences an increased arousal after exposure to a novel sexual partner) in estrogen-deprived male rats. Male rats (8 per group) were treated daily for 29 days with either saline (Control group) or fadrozole dissolved in saline (1 mg/kg/day) 1 h before mating. On Days 13 and 29, rats treated with fadrozole received either no additional treatment (fadrozole group) or a single injection of propyl-pyrazole-triol (ERα-agonist group, dissolved in sesame oil, 1 mg/kg). Rats mated until reaching sexual satiety on Days 13 and 29. In these sessions, the Control group displayed higher frequency of intromission and ejaculation than the other groups. The ERα-agonist group mounted more frequently but reached sexual satiety sooner than the Control group. On Day 29, when exposed to a new sexual partner, the fadrozole-treated rats were less likely to display intromission than the other groups, or ejaculation than the Control group, or mounting than the ERα-agonist group. The Control group showed more ejaculatory behavior and shorter ejaculation latency than the other groups. Body weights, testosterone levels, estradiol levels, and ERα-immunoreactive cell counts in brain regions for sexual behavior were comparable between groups after 29 days of treatments. Our data suggest that estrogen helps regulate sexual satiety and the Coolidge effect in male rats.
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Affiliation(s)
- P Hanna C Corre
- Department of Anatomy, University of Otago, Dunedin 9016, New Zealand.
| | | | - K Kenn Z Peralta
- Department of Anatomy, University of Otago, Dunedin 9016, New Zealand.
| | - P Mark Lokman
- Department of Zoology, University of Otago, Dunedin 9016, New Zealand.
| | - Robert Porteous
- Otago Micro and Nanoscale Imaging, University of Otago, Dunedin 9016, New Zealand.
| | - Erik Wibowo
- Department of Anatomy, University of Otago, Dunedin 9016, New Zealand.
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2
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Phillips-Farfán BV, Quintanar BG, Reyes R, Fernández-Guasti A. Distribution of estrogen receptors alpha and beta in the brain of male rats with same-sex preference. Physiol Behav 2023; 268:114237. [PMID: 37192686 DOI: 10.1016/j.physbeh.2023.114237] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 04/24/2023] [Accepted: 05/12/2023] [Indexed: 05/18/2023]
Abstract
Two distinct estrogen receptors (ERs) exist, ERα and ERβ. Both receptors participate in the sexual differentiation of the rat brain and likely participate in the regulation of adult sexual orientation (i.e. partner preference). This last idea was investigated herein by examining males treated with the aromatase inhibitor, letrozole, administered prenatally (0.56 μg/kg G10-22). This treatment usually provokes same-sex preference in 1-2 males per litter. Vehicle-treated males (with female preference) and females in spontaneous proestrus (with male preference) were included as controls. ERα and ERβ expression was analyzed by immunohistochemistry in brain areas known to control masculine sexual behavior and partner preference, like the medial preoptic area (MPOA), bed nucleus of the stria terminalis (BNST), medial amygdala (MeA) and ventromedial hypothalamic nucleus (VMH), as well as other brain regions suspected to participate in these processes. In addition, serum levels of estradiol were determined in all male groups. Letrozole-treated male rats that preferred sexually experienced males (LPM) showed over-expressed ERα in the hippocampal cornu Ammonis (CA 1, 3, 4) and dentate gyrus. The LPM group showed up-regulated ERβ expression in the CA2 and reticular thalamic nucleus. The levels of estradiol did not differ between the groups. The higher expression of ERs in these males was different than their expression in females, with male sex-preference. This suggests that males with same-sex preference showed a unique brain, this sui generis steroid receptor expression probably participates in the biological underpinnings of sexual preference.
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Affiliation(s)
| | | | - Rebeca Reyes
- Departament of Pharmacobiology, Cinvestav, Unidad Coapa
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3
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Fernández-Guasti A, Quintanar BG, Reyes R, Hernández A, Chavira R, Roselli CE. Androgen receptors immunoreactivity in the rat brain of males with same-sex preference. Horm Behav 2022; 146:105279. [PMID: 36370679 DOI: 10.1016/j.yhbeh.2022.105279] [Citation(s) in RCA: 3] [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: 06/30/2022] [Revised: 10/10/2022] [Accepted: 11/01/2022] [Indexed: 11/10/2022]
Abstract
Androgen receptors (AR) are crucial in the control of male sexual behavior and sex preference. AR are particularly concentrated in areas related with the neuroendocrine control of sex preference including the medial amygdala (MeA), the ventromedial nucleus of the hypothalamus (VMH), the bed nucleus of the stria terminalis (BNST), the medial preoptic area (MPOA), the nucleus accumbens (Acb), the suprachiasmatic (SCh) and supraoptic (SO) nuclei, but also seem to be important for the control of reproductive processes in the hippocampus (CA1-CA4 and dentate gyrus, DG). In the present study we analyzed the density of AR in these brain areas of adult male rats with sexual preference (established in a three-compartment box). Same-sex preference was produced in male rats by the prenatal administration of the aromatase inhibitor, letrozole (0.56 μg/kg/ml s.c. G10-22) that usually produces 1-2 animals per litter with same sex preference, while the others retain a female sex preference. We also included a group of proestrus females that had a clear preference for a sexually active male. AR were analyzed by immunocytochemistry using PG21 as primary antibody. We also measured total plasma testosterone concentrations by radioimmunoassay. In males with same sex preference there was a specific AR overexpression in CA3 and CA4 that suggests a feminized pattern because females in proestrus trend to show a higher density of AR in these hippocampal areas. Sex differences in AR density were found in the anterior cingulate cortex (ACg) and frontoparietal cortex (FrPa). Serum levels of testosterone did not differ between groups. Data are discussed based on the role of AR in the hippocampus.
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Affiliation(s)
| | | | - Rebeca Reyes
- Departament of Pharmacobiology, Cinvestav, Unidad Coapa, México City, Mexico
| | - Alejandra Hernández
- Departament of Pharmacobiology, Cinvestav, Unidad Coapa, México City, Mexico
| | - Roberto Chavira
- Departamento de Biología de la Reproducción, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, México City, Mexico
| | - Charles E Roselli
- Department of Chemical Physiology and Biochemistry, Oregon Health Science University, Portland, OR, USA
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Prevot V, Dehouck B, Sharif A, Ciofi P, Giacobini P, Clasadonte J. The Versatile Tanycyte: A Hypothalamic Integrator of Reproduction and Energy Metabolism. Endocr Rev 2018; 39:333-368. [PMID: 29351662 DOI: 10.1210/er.2017-00235] [Citation(s) in RCA: 147] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 01/12/2018] [Indexed: 12/16/2022]
Abstract
The fertility and survival of an individual rely on the ability of the periphery to promptly, effectively, and reproducibly communicate with brain neural networks that control reproduction, food intake, and energy homeostasis. Tanycytes, a specialized glial cell type lining the wall of the third ventricle in the median eminence of the hypothalamus, appear to act as the linchpin of these processes by dynamically controlling the secretion of neuropeptides into the portal vasculature by hypothalamic neurons and regulating blood-brain and blood-cerebrospinal fluid exchanges, both processes that depend on the ability of these cells to adapt their morphology to the physiological state of the individual. In addition to their barrier properties, tanycytes possess the ability to sense blood glucose levels, and play a fundamental and active role in shuttling circulating metabolic signals to hypothalamic neurons that control food intake. Moreover, accumulating data suggest that, in keeping with their putative descent from radial glial cells, tanycytes are endowed with neural stem cell properties and may respond to dietary or reproductive cues by modulating hypothalamic neurogenesis. Tanycytes could thus constitute the missing link in the loop connecting behavior, hormonal changes, signal transduction, central neuronal activation and, finally, behavior again. In this article, we will examine these recent advances in the understanding of tanycytic plasticity and function in the hypothalamus and the underlying molecular mechanisms. We will also discuss the putative involvement and therapeutic potential of hypothalamic tanycytes in metabolic and fertility disorders.
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Affiliation(s)
- Vincent Prevot
- Inserm, Laboratory of Development and Plasticity of the Neuroendocrine Brain, Jean-Pierre Aubert Research Center, Lille, France.,University of Lille, FHU 1000 Days for Health, School of Medicine, Lille, France
| | - Bénédicte Dehouck
- Inserm, Laboratory of Development and Plasticity of the Neuroendocrine Brain, Jean-Pierre Aubert Research Center, Lille, France.,University of Lille, FHU 1000 Days for Health, School of Medicine, Lille, France
| | - Ariane Sharif
- Inserm, Laboratory of Development and Plasticity of the Neuroendocrine Brain, Jean-Pierre Aubert Research Center, Lille, France.,University of Lille, FHU 1000 Days for Health, School of Medicine, Lille, France
| | - Philippe Ciofi
- Inserm, Neurocentre Magendie, Bordeaux, France.,Université de Bordeaux, Bordeaux, France
| | - Paolo Giacobini
- Inserm, Laboratory of Development and Plasticity of the Neuroendocrine Brain, Jean-Pierre Aubert Research Center, Lille, France.,University of Lille, FHU 1000 Days for Health, School of Medicine, Lille, France
| | - Jerome Clasadonte
- Inserm, Laboratory of Development and Plasticity of the Neuroendocrine Brain, Jean-Pierre Aubert Research Center, Lille, France.,University of Lille, FHU 1000 Days for Health, School of Medicine, Lille, France
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Ventura-Aquino E, Fernández-Guasti A, Paredes RG. Hormones and the Coolidge effect. Mol Cell Endocrinol 2018; 467:42-48. [PMID: 28912031 DOI: 10.1016/j.mce.2017.09.010] [Citation(s) in RCA: 9] [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: 04/18/2017] [Revised: 09/08/2017] [Accepted: 09/09/2017] [Indexed: 01/21/2023]
Abstract
The Coolidge effect is the renewal of sexual behavior after the presentation of a novel sexual partner and possibly occurs as the result of habituation and dishabituation processes. This re-motivation to copulate is well studied in males and is commonly related to sexual satiety, which involves several neurobiological changes in steroid receptors and their mRNA expression in the CNS. On the other hand, there are few reports studying sexual novelty in females and have been limited to behavioral aspects. Here we report that the levels of rat proceptive behavior, a sign of sexual motivation, declines after 4 h of continuous mating, particularly in females that were unable to regulate the time of mating. Such reduction was not accompanied by changes in lordosis, suggesting that they were not due to the vanishing of the endocrine optimal milieu necessary for the expression of both components of sexual behavior in the female rat. These and previous data support important differences between sexual behavior in both sexes that would result in natural divergences in the Coolidge effect expression. We here also review some reports in humans showing peculiarities between the pattern of habituation and dishabituation in women and men. This is a growing research field that needs emphasis in female subjects.
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Affiliation(s)
- Elisa Ventura-Aquino
- Instituto de Neurobiología, Universidad Nacional Autónoma de México, Querétaro, Mexico; Departamento de Farmacobiología, CINVESTAV-Sede Sur, Mexico.
| | | | - Raúl G Paredes
- Instituto de Neurobiología, Universidad Nacional Autónoma de México, Querétaro, Mexico
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6
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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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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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8
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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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He F, Yu P, Wu R. Relationship between sexual satiety and motivation, brain androgen receptors and testosterone in male mandarin voles. Behav Brain Res 2013; 250:257-63. [PMID: 23707935 DOI: 10.1016/j.bbr.2013.05.022] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2013] [Revised: 05/09/2013] [Accepted: 05/14/2013] [Indexed: 10/26/2022]
Abstract
Androgen receptors participate in the neuroendocrine regulation of male sexual behavior, primarily in brain areas located in the limbic system. Males of many species present a long-term inhibition of sexual behavior after several ejaculations, known as sexual satiety. It has been shown in rats that androgen receptor expression is reduced 24h after a single ejaculation, or mating to satiety, in the medial preoptic area, nucleus accumbens and ventromedial hypothalamus. The aim of this study was to analyze these processes in another animal, the mandarin vole (Microtus mandarinus). We compared differences in androgen receptor (AR) and testosterone (T) expression in various brain areas between male mandarin voles sexually satiated and those exposed to receptive females but not allowed to mate. Sexual satiety was associated with decreased AR and T expression in the lateral septal nucleus (LS), medial amygdala (MeA), medial preoptic area (mPOA) and ventromedial hypothalamic nucleus (VMH). Males exposed to receptive females showed an increase in AR and T expression in the bed nucleus of the stria terminalis (BNST), LS, MeA and VMH. Serum testosterone levels remained unchanged after 24h in males exposed to receptive females or males mated to satiety. These data suggest a relationship between sexual activity and a decrease in AR and T expression in specific brain areas, and a relationship between sexual motivation and increased AR and T expression in other brain areas, independently of testosterone levels.
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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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Swaney WT, Dubose BN, Curley JP, Champagne FA. Sexual experience affects reproductive behavior and preoptic androgen receptors in male mice. Horm Behav 2012; 61:472-8. [PMID: 22266118 PMCID: PMC3319191 DOI: 10.1016/j.yhbeh.2012.01.001] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Revised: 12/20/2011] [Accepted: 01/03/2012] [Indexed: 10/14/2022]
Abstract
Reproductive behavior in male rodents is made up of anticipatory and consummatory elements which are regulated in the brain by sensory systems, reward circuits and hormone signaling. Gonadal steroids play a key role in the regulation of male sexual behavior via steroid receptors in the hypothalamus and preoptic area. Typical patterns of male reproductive behavior have been characterized, however these are not fixed but are modulated by adult experience. We assessed the effects of repeated sexual experience on male reproductive behavior of C57BL/6 mice; including measures of olfactory investigation of females, mounting, intromission and ejaculation. The effects of sexual experience on the number of cells expressing either androgen receptor (AR) or estrogen receptor alpha (ERα) in the primary brain nuclei regulating male sexual behavior was also measured. Sexually experienced male mice engaged in less sniffing of females before initiating sexual behavior and exhibited shorter latencies to mount and intromit, increased frequency of intromission, and increased duration of intromission relative to mounting. No changes in numbers of ERα-positive cells were observed, however sexually experienced males had increased numbers of AR-positive cells in the medial preoptic area (MPOA); the primary regulatory nucleus for male sexual behavior. These results indicate that sexual experience results in a qualitative change in male reproductive behavior in mice that is associated with increased testosterone sensitivity in the MPOA and that this nucleus may play a key integrative role in mediating the effects of sexual experience on male behavior.
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Affiliation(s)
- William T Swaney
- Behavioural Biology and Helmholtz Institute, Utrecht University, 3508 TB Utrecht, The Netherlands
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Stolzenberg DS, Numan M. Hypothalamic interaction with the mesolimbic DA system in the control of the maternal and sexual behaviors in rats. Neurosci Biobehav Rev 2011; 35:826-47. [DOI: 10.1016/j.neubiorev.2010.10.003] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2010] [Revised: 10/05/2010] [Accepted: 10/06/2010] [Indexed: 12/25/2022]
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Fernández-Guasti A, Arteaga-López P, Antonio-Cabrera E. Copulation modifies AR and ERα mRNA expression in the male rat brain. Physiol Behav 2010; 101:738-45. [PMID: 20804777 DOI: 10.1016/j.physbeh.2010.08.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2010] [Revised: 08/13/2010] [Accepted: 08/23/2010] [Indexed: 01/03/2023]
Abstract
BACKGROUND/AIMS One day after male sexual behavior [one ejaculation or copulation to satiety (ad libitum copulation during 4h with the same female)] androgen receptor immunoreactivity (AR-ir) is decreased and estrogen receptor alpha immunoreactivity (ERα-ir) increased in various brain areas related with its control. Seven days after sexual satiety there was a limited recovery of sexual behavior accompanied by a partial recuperation in the AR-ir. In this study we evaluated if these changes in AR-ir and ERα-ir were paralleled by variations in their respective mRNA. METHODS Sexually experienced male rats were sacrificed at different intervals: immediately, 24h or seven days after sexual satiety or 24h after one ejaculation. The changes in AR and ERα mRNA were analyzed by in situ hybridization using digoxigenine-labeled oligonucleotide probes in the MPOA, LSV and the bed nucleus of the stria terminalis, medial division, anterior (BSTMA). RESULTS AR mRNA density was decreased in the MPOA and the LSV immediately and 24h after one ejaculation or sexual satiety. Seven days after copulating to satiety, there was a recovery of AR mRNA. In the BSTMA the different behavioral conditions did not modify the AR mRNA expression. In the MPOA, LSV and BSTMA the ERα mRNA increased after a single ejaculation and at all intervals after sexual satiety. CONCLUSION In some brain areas and after some intervals of sexual activity, the changes in steroid protein receptors expression seem to be consequence of parallel changes in the expression of the respective mRNA.
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Affiliation(s)
- Alonso Fernández-Guasti
- Department of Pharmacobiology, CINVESTAV, Calzada de los Tenorios 235, Col. Granjas Coapa, Del. Tlalpan, México City, D. F. 14330 México.
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13
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Prevot V, Bellefontaine N, Baroncini M, Sharif A, Hanchate NK, Parkash J, Campagne C, de Seranno S. Gonadotrophin-releasing hormone nerve terminals, tanycytes and neurohaemal junction remodelling in the adult median eminence: functional consequences for reproduction and dynamic role of vascular endothelial cells. J Neuroendocrinol 2010; 22:639-49. [PMID: 20492366 PMCID: PMC3168864 DOI: 10.1111/j.1365-2826.2010.02033.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Although coordinated actions of several areas within the hypothalamus are involved in the secretion of gonadotrophin-releasing hormone (GnRH), the median eminence of the hypothalamus, where the nerve terminals are located, plays a particularly critical role in the release of GnRH. In adult females, prior to the preovulatory surge of GnRH, the retraction of specialised ependymoglial cells lining the floor of the third ventricle named tanycytes allows for the juxtaposition of GnRH nerve terminals with the adjacent pericapillary space of the pituitary portal vasculature, thus forming direct neurohaemal junctions. These morphological changes occur within a few hours and are reversible. Such remodelling may promote physiological conditions to enhance the central release of GnRH and potentiate oestrogen-activated GnRH release. This plasticity involves dynamic cell interactions that bring into play tanycytes, astrocytes, vascular endothelial cells and GnRH neurones themselves. The underlying signalling pathways responsible for these structural changes are comprised of highly diffusible gaseous molecules, such as endothelial nitric oxide, and paracrine communication processes involving receptors of the erbB tyrosine kinase family, transforming growth factor beta 1 and eicosanoids, such as prostaglandin E(2). Some of these molecules, as a result of their ability to diffuse within the median eminence, may also serve as synchronizing cues allowing for the occurrence of functionally meaningful episodes of GnRH secretion by coordinating GnRH release from the GnRH neuroendocrine terminals.
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Affiliation(s)
- V Prevot
- Inserm, Jean-Pierre Aubert Research Center, U837, Development and Plasticity of the Postnatal Brain, Lille, France.
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Wu D, Gore AC. Changes in androgen receptor, estrogen receptor alpha, and sexual behavior with aging and testosterone in male rats. Horm Behav 2010; 58:306-16. [PMID: 20223236 PMCID: PMC2879440 DOI: 10.1016/j.yhbeh.2010.03.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2009] [Revised: 02/26/2010] [Accepted: 03/01/2010] [Indexed: 11/16/2022]
Abstract
Reproductive aging in males is characterized by a diminution in sexual behavior beginning in middle age. We investigated the relationships among testosterone, androgen receptor (AR) and estrogen receptor alpha (ERalpha) cell numbers in the hypothalamus, and their relationship to sexual performance in male rats. Young (3months) and middle-aged (12months) rats were given sexual behavior tests, then castrated and implanted with vehicle or testosterone capsules. Rats were tested again for sexual behavior. Numbers of AR and ERalpha immunoreactive cells were counted in the anteroventral periventricular nucleus and the medial preoptic nucleus, and serum hormones were measured. Middle-aged intact rats had significant impairments of all sexual behavior measures compared to young males. After castration and testosterone implantation, sexual behaviors in middle-aged males were largely comparable to those in the young males. In the hypothalamus, AR cell density was significantly (5-fold) higher, and ERalpha cell density significantly (6-fold) lower, in testosterone- than vehicle-treated males, with no age differences. Thus, restoration of serum testosterone to comparable levels in young and middle-aged rats resulted in similar preoptic AR and ERalpha cell density concomitant with a reinstatement of most behaviors. These data suggest that age-related differences in sexual behavior cannot be due to absolute levels of testosterone, and further, the middle-aged brain retains the capacity to respond to exogenous testosterone with changes in hypothalamic AR and ERalpha expression. Our finding that testosterone replacement in aging males has profound effects on hypothalamic receptors and behavior has potential medical implications for the treatment of age-related hypogonadism in men.
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Affiliation(s)
- Di Wu
- Division of Pharmacology & Toxicology, College of Pharmacy; The University of Texas at Austin, Austin, TX, 78712, USA
| | - Andrea C. Gore
- Division of Pharmacology & Toxicology, College of Pharmacy; The University of Texas at Austin, Austin, TX, 78712, USA
- Institute for Neuroscience; The University of Texas at Austin, Austin, TX, 78712, USA
- Institute for Cellular & Molecular Biology; The University of Texas at Austin, Austin, TX, 78712, USA
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Spary EJ, Maqbool A, Batten TFC. Changes in oestrogen receptor alpha expression in the nucleus of the solitary tract of the rat over the oestrous cycle and following ovariectomy. J Neuroendocrinol 2010; 22:492-502. [PMID: 20236229 DOI: 10.1111/j.1365-2826.2010.01977.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Oestrogen is capable of modulating autonomic outflow and baroreflex function via actions on groups of neurones in the brainstem. We investigated the presence of oestrogen receptor (ER) alpha in a part of the nucleus of the solitary tract (NTS) associated with central cardiovascular control, aiming to determine whether ERalpha mRNA and protein expression is correlated with levels of circulating oestrogen during the oestrous cycle. Polymerase chain reaction (PCR) detected ERalpha mRNA in the NTS at each stage of the oestrous cycle, from ovariectomised, sham-operated and male rats. Real-time PCR showed variations in ERalpha mRNA expression during the oestrous cycle, with the highest levels seen in oestrus, and lowest levels in metoestrus (P < 0.05 versus oestrus) and proestrus (P < 0.05 versus oestrus). Expression in males was lower than in dioestrus and oestrus females (P < 0.05). After ovariectomy, ERalpha mRNA levels were decreased compared to sham-operated animals (P < 0.01). Confocal fluorescence immunohistochemistry with stereological analysis showed that numbers of ERalpha immunoreactive cell nuclei per mm(3) of tissue in the caudal NTS were significantly greater in proestrus than in other groups of rats (P < 0.05). There were also differences among the groups in the extent of colocalisation of ERalpha in neurones immunoreactive for tyrosine hydroxylase and nitric oxide synthase. These results imply a complex pattern of region-specific oestrogen signalling in the NTS and suggest that ERalpha expression in this important autonomic nucleus may be related to circulating oestrogen levels. This may have consequences for the regulation of autonomic tone and baroreflex sensitivity when oestrogen levels decline, for example following menopause.
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Affiliation(s)
- E J Spary
- Division of Cardiovascular and Neuronal Remodelling, LIGHT Institute, University of Leeds, Leeds, UK.
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Salas-Ramirez KY, Montalto PR, Sisk CL. Anabolic steroids have long-lasting effects on male social behaviors. Behav Brain Res 2009; 208:328-35. [PMID: 20036695 DOI: 10.1016/j.bbr.2009.11.026] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2009] [Revised: 09/21/2009] [Accepted: 11/16/2009] [Indexed: 12/17/2022]
Abstract
Anabolic androgenic steroids (AAS) use by adolescents is steadily increasing. Adolescence involves remodeling of steroid-sensitive neural circuits that mediate social behaviors, and previous studies using animal models document effects of AAS on male social behaviors. The present experiments tested whether AAS have persistent and more pronounced behavioral consequences when drug exposure occurs during adolescence as compared to exposure in adulthood. Male Syrian hamsters were injected daily for 14 days with either vehicle or an AAS cocktail containing testosterone cypionate (2 mg/kg), nandrolone decanoate (2 mg/kg), and boldenone undecylenate (1 mg/kg), either during adolescence (27-41 days of age) or adulthood (63-77 days of age). As adults, subjects were tested two or four weeks after the last injection for either sexual behavior with a receptive female or male-male agonistic behavior in a resident-intruder test. Compared with vehicle-treated males, AAS-treated males, regardless of age of treatment, displayed fewer long intromissions and a significant increase in latency to the first long intromission, indicative of reduced potential to reach sexual satiety. Increased aggression was observed in males exposed to AAS compared with males treated with vehicle, independently of age of AAS treatment. However, unlike hamsters exposed to AAS in adulthood, hamsters exposed to AAS during adolescence did not display any submissive or risk-assessment behaviors up to 4 weeks after discontinuation of AAS treatment. Thus, AAS have long-lasting effects on male sexual and agonistic behaviors, with AAS exposure during adolescence resulting in a more pronounced reduction in submissive behavior compared to AAS exposure in adulthood.
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Wu D, Gore AC. Sexual experience changes sex hormones but not hypothalamic steroid hormone receptor expression in young and middle-aged male rats. Horm Behav 2009; 56:299-308. [PMID: 19559704 PMCID: PMC2739266 DOI: 10.1016/j.yhbeh.2009.06.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2009] [Revised: 06/13/2009] [Accepted: 06/17/2009] [Indexed: 11/22/2022]
Abstract
Testosterone is well known to regulate sexual behavior in males, but this is dependent upon prior sexual experience. Aging is associated with decreased libido and changes in testosterone, but the role of experience in these age-related processes has not been systematically studied. We examined effects of age and sexual experience on serum hormones (total testosterone, free testosterone, estradiol, LH) and on numbers of androgen receptor (AR) and estrogen receptor alpha (ERalpha) immunoreactive cells in the hypothalamus. Extensive sexual experience was given to male rats at 4 months of age. Rats were euthanized at either 4 months (young) or 12 months (middle-aged (MA)). Comparable sexually naïve male rats were handled and placed into the testing arena but did not receive any sexual experience. Thus, we had four groups: young-naïve, young-experienced, MA-naïve and MA-experienced. Serum hormone levels were assayed, and numbers of AR and ERalpha cells were quantified stereologically in the medial preoptic nucleus (MPN) and the anteroventral periventricular nucleus (AVPV). Sexually experienced males had significantly elevated serum testosterone and free testosterone in both age groups. Both total and free testosterone were higher, and estradiol lower, in middle-aged than young rats. Experience did not alter either AR or ERalpha expression in the preoptic brain regions studied. Aging was associated with increased expression of AR, but no change in ERalpha. These results show that sexual experience can induce short-term and long-term alterations in serum hormones but these effects are not manifested upon their receptors in the hypothalamus.
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Affiliation(s)
- Di Wu
- Division of Pharmacology & Toxicology, College of Pharmacy; The University of Texas at Austin, Austin, TX, 78712, USA
| | - Andrea C. Gore
- Division of Pharmacology & Toxicology, College of Pharmacy; The University of Texas at Austin, Austin, TX, 78712, USA
- Institute for Neuroscience; The University of Texas at Austin, Austin, TX, 78712, USA
- Institute for Cellular & Molecular Biology; The University of Texas at Austin, Austin, TX, 78712, USA
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Wu D, Lin G, Gore AC. Age-related changes in hypothalamic androgen receptor and estrogen receptor alpha in male rats. J Comp Neurol 2009; 512:688-701. [PMID: 19051266 DOI: 10.1002/cne.21925] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The control of reproductive function involves actions of sex steroids upon their nuclear receptors in the hypothalamus and preoptic area (POA). Whether hypothalamic hormone receptors change their expression in aging male mammals has not been extensively pursued, although such changes may underlie functional losses in reproductive physiology occurring with aging. We performed a stereologic analysis of immunoreactive androgen receptor (AR) and estrogen receptor alpha (ERalpha) cells in three POA nuclei of male Sprague-Dawley rats (anteroventral periventricular nucleus [AVPV], median preoptic area [MePO], and medial preoptic nucleus [MPN]), at young (3 months), middle-aged (12 months), and old (20 months) ages. Serum testosterone and estradiol levels were assayed. Testosterone concentrations decreased significantly and progressively with aging. Estradiol concentrations were significantly higher in middle-aged than either young or old rats. Stereologic analyses of the POA demonstrated that AR-immunoreactive cell numbers and density in the AVPV, MePO, and MPN were significantly higher in old compared with young or middle-aged rats. No change in the total number or density of ERalpha-immunoreactive cells was detected with age, although when cells were subdivided by intensity of immunolabeling, the most heavily labeled ERalpha cells increased in number with aging in the AVPV and MePO, and in density in the AVPV. There are several interpretations to our finding of substantially increased AR cell numbers during aging, including a potential compensatory upregulation of the AR under diminished testosterone concentrations. These results provide further information about how the neural targets of steroid hormones change with advancing age.
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Affiliation(s)
- Di Wu
- Division of Pharmacology & Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, Texas 78712, USA
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Timonin ME, Cushing BS, Wynne-Edwards KE. In three brain regions central to maternal behaviour, neither male nor female Phodopus dwarf hamsters show changes in oestrogen receptor alpha distribution with mating or parenthood. J Neuroendocrinol 2008; 20:1301-9. [PMID: 19094078 DOI: 10.1111/j.1365-2826.2008.01797.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Oestrogen receptor (ER)alpha immunoreactivity in three brain regions relevant to maternal behaviour (medial preoptic area, bed nucleus of the stria terminalis and medial amygdala) was measured in two species of dwarf hamster that both mate during a postpartum oestrous but differ in expression of paternal behaviour. Male and female Phodopus campbelli and Phodopus sungorus were sampled as sexually naive adults, following mating to satiety, and as new parents. In all brain regions, females expressed higher levels of ER alpha than males. Species did not have an effect on ER alpha distribution except in the medial amygdala, where P. sungorus females had higher expression levels than all other groups. Behavioural status was not associated with altered ER alpha expression. These results were not expected for females and suggest that a primary activational role for oestrogen, acting through ER alpha in these regions, does not generalize to maternal behaviour in Phodopus. In males, these results are consistent with previous manipulations of the ER alpha ligand, oestrogen, and suggest that paternal behaviour in P. campbelli is likely to be regulated by developmental effects of oestrogen on the brain during early life (similar to Microtus ochrogaster), rather than through activation by oestrogen at the time of fatherhood (similar to Peromyscus californicus).
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Affiliation(s)
- M E Timonin
- Department of Biology, Queen's University, Kingston, ON, Canada
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Abstract
A unique challenge posed by advancing scientific knowledge about the biology of human behavior is how to integrate that understanding with the desire to hold ourselves--and one another--morally accountable. As human beings, we are something more than just passive agents whose behavior is the sum product of biologic determinism. Because of the existence of the mind, we are also active agents with the capacity to influence, at least to some extent, our own destinies. Behavior may be determined, but it is not predetermined. We are one of its determinants. Misconduct by a person of sound mind should not be attributed improperly to brain pathology. On the other hand, suffering, legitimate mental disorder, and associated impairments should not be trivialized. Historically, persons who once were labeled "lazy" are often more appropriately understood by modern standards as clinically depressed. Frequently they are more in need of pharmacologic treatments that alter brain chemistry than "a kick in the behind." Gluttony, one of the original cardinal sins, is often more properly understood as morbid obesity, a condition that deserves appropriate medical care. Persons who have alcoholism, once judged morally as "bums in the gutter," are more frequently referred to treatment facilities, such as The Betty Ford Clinic. One should not approach the issue of human sexual behavior without at least some appreciation of moral values and scientific research. Although clearly some persons choose to act in a sexually selfish and self-indulgent fashion with wanton disregard, others seem to be more genuinely burdened and struggle to integrate their sexual desires into an otherwise healthy and fully responsible lifestyle. When a person, whether male or female, seems to be so driven that it becomes difficult to master erotic desires and he or she experiences difficulty serving his or her own best longterm interests, the concept of sexual compulsivity seems to be relevant. Ultimately, a better understanding of any associated neuropathologies may help to facilitate future treatments and public acceptance. The possibility exists, at least in some instances, that a sexually compulsive individual is less an example of a bad person deserving of punishment than a "broken mind" in need of repair. In time, increased knowledge about the precise workings of the brain in reciprocally initiating and sustaining the sexual interests of the mind may facilitate a much clearer appreciation of the issues at hand.
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Affiliation(s)
- Fred S Berlin
- Department of Psychiatry and Behavioral Sciences, The John Hopkins University School of Medicine, Baltimore, MD, USA.
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Phillips-Farfán BV, Romano-Torres M, Fernández-Guasti A. Anabolic androgens restore mating after sexual satiety in male rats. Pharmacol Biochem Behav 2007; 89:241-6. [PMID: 18234307 DOI: 10.1016/j.pbb.2007.12.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2007] [Revised: 12/07/2007] [Accepted: 12/14/2007] [Indexed: 10/22/2022]
Abstract
Androgen receptors and estrogen receptors importantly participate in the neuroendocrine control of masculine mating behavior. Sexual satiety is the long term inhibition of masculine mating behavior after repeated ejaculations and is associated to changes in both androgen receptor and estrogen receptor-alpha expression. Androgen receptor expression is up-regulated by systemic chronic administration of anabolic androgens, 5alpha-dihydrotestosterone or estradiol benzoate. This study was carried out to investigate the effect of these treatments on sexual satiety development and recovery; additionally flutamide or tamoxifen treatments -- alone or together with anabolic androgens -- were also included. Chronic 15-day treatment with 5alpha-dihydrotestosterone (5 mg/kg) or tamoxifen (15 mg/kg) inhibited, whereas estradiol benzoate treatment (5 mg/kg) facilitated, mating behavior during sexual satiety development. The proportion of animals that ejaculated 48 h after sexual satiety was increased after 17-day treatment with a mixture of anabolic androgens containing 2 mg/kg testosterone propionate, 2 mg/kg nandrolone decanoate and 1 mg/kg boldenone undecylenate. This effect was only blocked by the combined administration of flutamide plus tamoxifen. The data suggest that anabolic androgens metabolites synergize to restore mating behavior after sexual satiety.
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Phillips-Farfán BV, Fernández-Guasti A. c-Fos expression related to sexual satiety in the male rat forebrain. Physiol Behav 2007; 91:609-19. [PMID: 17482654 DOI: 10.1016/j.physbeh.2007.03.024] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2006] [Revised: 02/02/2007] [Accepted: 03/26/2007] [Indexed: 12/16/2022]
Abstract
The long term inhibition of masculine sexual behavior after repeated ejaculations is known as sexual satiety. To investigate the brain areas that may regulate sexual satiety, c-Fos expression was studied in different groups of sexually experienced male rats: controls not allowed to copulate, males allowed two or four ejaculations and animals allowed to reach sexual satiety. Interestingly, males that ejaculated two or four times had similar c-Fos densities in all the evaluated brain regions, except for the suprachiasmatic nucleus. Similarly, sexually satiated males had analogous c-Fos densities in all the evaluated brain areas independently of the number of ejaculations required to reach satiety. Sexual activity (evidenced in males that ejaculated two or four times) increased c-Fos levels in the anteromedial bed nucleus of the stria terminalis, claustrum, entorhinal cortex, medial preoptic area, nucleus accumbens core, suprachiasmatic nucleus and supraoptic nucleus; however, sexual satiety did not modify c-Fos expression in these regions. Sexually satiated males had increased c-Fos densities in the ventrolateral septum and the anterodorsal and posteroventral medial amygdala, compared with animals allowed to copulate but that did not reach sexual satiety, and decreased c-Fos density in the piriform cortex. These results suggest that the network that underlies sexual satiety is different from that which regulates copulation.
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