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Qin Z, He X, Gao Q, Li Y, Zhang Y, Wang H, Qin N, Wang C, Huang B, Shi Y, Liu C, Wang S, Zhang H, Li Y, Shi H, Tian X, Song L. Postweaning sodium citrate exposure induces long-lasting and sex-dependent effects on social behaviours in mice. Pharmacol Biochem Behav 2024; 242:173807. [PMID: 38925482 DOI: 10.1016/j.pbb.2024.173807] [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: 05/09/2024] [Revised: 06/12/2024] [Accepted: 06/13/2024] [Indexed: 06/28/2024]
Abstract
BACKGROUND Postweaning is a pivotal period for brain development and individual growth. As an important chemical used in medicines, foods and beverages, sodium citrate (SC) is commonly available. Although some effects of SC exposure on individual physiology have been demonstrated, the potential long-lasting effects of postweaning dietary SC exposure on social behaviours are still elusive. METHODS Both postweaning male and female C57BL/6 mice were exposed to SC through drinking water for a total of 3 weeks. A series of behavioural tests, including social dominance test (SDT), social interaction test (SIT), bedding preference test (BPT) and sexual preference test (SPT), were performed in adolescence and adulthood. After these tests, serum oxytocin (OT) levels and gut microbiota were detected. RESULTS The behavioural results revealed that postweaning SC exposure decreased the social dominance of male mice in adulthood and female mice in both adolescence and adulthood. SC exposure also reduced the sexual preference rates of both males and females, while it had no effect on social interaction behaviour. ELISA results indicated that SC exposure decreased the serum OT levels of females but not males. 16S rRNA sequencing analysis revealed a significant difference in β-diversity after SC exposure in both males and females. The correlation coefficient indicated the correlation between social behaviours, OT levels and dominant genera of gut microbiota. CONCLUSION Our findings suggest that postweaning SC exposure may have enduring and sex-dependent effects on social behaviours, which may be correlated with altered serum OT levels and gut microbiota composition.
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Affiliation(s)
- Zihan Qin
- Neuroscience Research Center, Institute of Medical and Health Science of Hebei Medical University, Shijiazhuang 050017, China
| | - Xinyue He
- Neuroscience Research Center, Institute of Medical and Health Science of Hebei Medical University, Shijiazhuang 050017, China
| | - Qiang Gao
- Neuroscience Research Center, Institute of Medical and Health Science of Hebei Medical University, Shijiazhuang 050017, China; Hebei Key Laboratory of Neurophysiology (SZX2020013), Hebei Medical University, 050017, China
| | - Yuxin Li
- Neuroscience Research Center, Institute of Medical and Health Science of Hebei Medical University, Shijiazhuang 050017, China
| | - Yue Zhang
- Neuroscience Research Center, Institute of Medical and Health Science of Hebei Medical University, Shijiazhuang 050017, China
| | - Huajian Wang
- Neuroscience Research Center, Institute of Medical and Health Science of Hebei Medical University, Shijiazhuang 050017, China
| | - Na Qin
- Neuroscience Research Center, Institute of Medical and Health Science of Hebei Medical University, Shijiazhuang 050017, China
| | - Chen Wang
- Neuroscience Research Center, Institute of Medical and Health Science of Hebei Medical University, Shijiazhuang 050017, China
| | - Boya Huang
- Neuroscience Research Center, Institute of Medical and Health Science of Hebei Medical University, Shijiazhuang 050017, China; Hebei Key Laboratory of Neurophysiology (SZX2020013), Hebei Medical University, 050017, China
| | - Yun Shi
- Neuroscience Research Center, Institute of Medical and Health Science of Hebei Medical University, Shijiazhuang 050017, China; Hebei Key Laboratory of Neurophysiology (SZX2020013), Hebei Medical University, 050017, China
| | - Congcong Liu
- Neuroscience Research Center, Institute of Medical and Health Science of Hebei Medical University, Shijiazhuang 050017, China; Early Life Health Research Center, Hebei Medical University, Shijiazhuang 050017, China
| | - Sheng Wang
- Neuroscience Research Center, Institute of Medical and Health Science of Hebei Medical University, Shijiazhuang 050017, China; Hebei Key Laboratory of Neurophysiology (SZX2020013), Hebei Medical University, 050017, China
| | - Huifeng Zhang
- Neuroscience Research Center, Institute of Medical and Health Science of Hebei Medical University, Shijiazhuang 050017, China; Department of Pediatrics, The Second Hospital of Hebei Medical University, Shijiazhuang 050017, China; Early Life Health Research Center, Hebei Medical University, Shijiazhuang 050017, China
| | - Youdong Li
- Neuroscience Research Center, Institute of Medical and Health Science of Hebei Medical University, Shijiazhuang 050017, China; Early Life Health Research Center, Hebei Medical University, Shijiazhuang 050017, China
| | - Haishui Shi
- Neuroscience Research Center, Institute of Medical and Health Science of Hebei Medical University, Shijiazhuang 050017, China; Hebei Key Laboratory of Neurophysiology (SZX2020013), Hebei Medical University, 050017, China; Research Unit of Digestive Tract Microecosystem Pharmacology and Toxicology, Chinese Academy of Medical Sciences, Shijiazhuang 050017, China; Early Life Health Research Center, Hebei Medical University, Shijiazhuang 050017, China
| | - Xiaoyu Tian
- Neuroscience Research Center, Institute of Medical and Health Science of Hebei Medical University, Shijiazhuang 050017, China; Department of Pediatrics, The Second Hospital of Hebei Medical University, Shijiazhuang 050017, China.
| | - Li Song
- Neuroscience Research Center, Institute of Medical and Health Science of Hebei Medical University, Shijiazhuang 050017, China; Hebei Key Laboratory of Neurophysiology (SZX2020013), Hebei Medical University, 050017, China.
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Hayashi H, Shimizu K, Nakamura K, Nishimori K, Kondo Y. The bilevel chamber revealed differential involvement of vasopressin and oxytocin receptors in female mouse sexual behavior. PLoS One 2024; 19:e0304703. [PMID: 38900750 PMCID: PMC11189176 DOI: 10.1371/journal.pone.0304703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2023] [Accepted: 05/17/2024] [Indexed: 06/22/2024] Open
Abstract
Arginine vasopressin (AVP) and oxytocin (OT) are well-known as neuropeptides that regulate various social behaviors in mammals. However, little is known about their role in mouse female sexual behavior. Thus, we investigated the role of AVP (v1a and v1b) and OT receptors on female sexual behavior. First, we devised a new apparatus, the bilevel chamber, to accurately observe female mouse sexual behavior. This apparatus allowed for a more precisely measurement of lordosis as receptivity and rejection-like behavior (newly defined in this study), a reversed expression of proceptivity. To address our research question, we evaluated female sexual behavior in mice lacking v1a (aKO), v1b (bKO), both v1a and v1b (dKO), and OT (OTRKO) receptors. aKO females showed decreased rejection-like behavior but a normal level of lordosis, whereas bKO females showed almost no lordosis and no change in rejection-like behavior. In addition, dKO females showed normal lordosis levels, suggesting that the v1b receptor promotes lordosis, but not necessarily, while the v1a receptor latently suppresses it. In contrast, although OTRKO did not influence lordosis, it significantly increased rejection-like behavior. In summary, the present results demonstrated that the v1a receptor inhibits proceptivity and receptivity, whereas the v1b and OT receptors facilitate receptivity and proceptivity, respectively.
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Affiliation(s)
- Himeka Hayashi
- Department of Animal Sciences, Teikyo University of Science, Yamanashi, Japan
| | - Kie Shimizu
- Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
- Department of Pharmacology, National Research Institute for Child Health and Development, Tokyo, Japan
| | - Kazuaki Nakamura
- Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
- Department of Pharmacology, National Research Institute for Child Health and Development, Tokyo, Japan
| | - Katsuhiko Nishimori
- Department of Obesity and Internal Inflammation, Fukushima Medical University, Fukushima, Japan
| | - Yasuhiko Kondo
- Department of Animal Sciences, Teikyo University of Science, Yamanashi, Japan
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Dale II J, Harberson MT, Hill JW. From Parental Behavior to Sexual Function: Recent Advances in Oxytocin Research. CURRENT SEXUAL HEALTH REPORTS 2024; 16:119-130. [PMID: 39224135 PMCID: PMC11365839 DOI: 10.1007/s11930-024-00386-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/02/2024] [Indexed: 09/04/2024]
Abstract
Purpose of Review Oxytocin plays many diverse roles in physiological and behavioral processes, including social activity, parental nurturing, stress responses, and sexual function. In this narrative review, we provide an update on the most noteworthy recent findings in this fascinating field. Recent Findings The development of techniques such as serial two-photon tomography and fiber photometry have provided a window into oxytocin neuroanatomy and real-time neuronal activity during social interactions. fMRI and complementary mapping techniques offer new insights into oxytocin's influence on brain activity and connectivity. Indeed, oxytocin has recently been found to influence the acquisition of maternal care behaviors and to mediate the influence of social touch on brain development and social interaction. Additionally, oxytocin plays a crucial role in male sexual function, affecting erectile activity and ejaculation, while its role in females remains controversial. Recent studies also highlight oxytocin's interaction with other neuropeptides, such as melanin-concentrating hormone, serotonin, and arginine vasopressin, influencing social and affective behaviors. Finally, an update is provided on the status of clinical trials involving oxytocin as a therapeutic intervention. Summary The exploration of oxytocin's complexities and its interplay with other neuropeptides holds promise for targeted treatment in various health and disease contexts. Overall, these findings contribute to the discovery of new and specific pathways to allow therapeutic targeting of oxytocin to treat disorders.
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Affiliation(s)
- Joseph Dale II
- Department of Physiology and Pharmacology, University of Toledo College of Medicine, Toledo, OH USA
- Department of Biology, University of Toledo College of Medicine, Toledo, OH USA
| | - Mitchell T. Harberson
- Center for Diabetes and Endocrine Research, University of Toledo College of Medicine, Toledo, OH USA
- Department of Physiology and Pharmacology, University of Toledo College of Medicine, Toledo, OH USA
| | - Jennifer W. Hill
- Center for Diabetes and Endocrine Research, University of Toledo College of Medicine, Toledo, OH USA
- Department of Physiology and Pharmacology, University of Toledo College of Medicine, Toledo, OH USA
- Department of Obstetrics and Gynecology, University of Toledo College of Medicine, Toledo, OH USA
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Hao Y, Guo X, Wang X, Shi X, Shi M, Meng L, Gong M, Fu Y, Zhao Y, Du Y, Yang R, Li W, Lian K, Song L, Wang S, Li Y, Shi Y, Shi H. Maternal exposure to triclosan during lactation alters social behaviors and the hippocampal ultrastructure in adult mouse offspring. Toxicol Appl Pharmacol 2022; 449:116131. [PMID: 35718130 DOI: 10.1016/j.taap.2022.116131] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 05/08/2022] [Accepted: 06/11/2022] [Indexed: 10/18/2022]
Abstract
We recently reported that exposure to triclosan (TCS), a broad-spectrum antibacterial agent, affects social behaviors in adult mice, however, the long-lasting effects of TCS exposure during early life on social behaviors are still elusive. The present study aimed to investigate the long-lasting impacts of adding TCS to the maternal drinking water during lactation on the social behaviors of adult mouse offspring and to explore the potential mechanism underlying these effects. The behavioral results showed that TCS exposure decreased body weight, increased depression-like behavior and decreased social dominance in both male and female offspring, as well as increased anxiety-like behavior and bedding preference in female offspring. In addition, enzyme-linked immunosorbent assay (ELISA) indicated that TCS exposure increased peripheral proinflammatory cytokine levels, altered serum oxytocin (OT) levels, and downregulated the expression of postsynaptic density protein 95 (PSD-95) in the hippocampus. Morphological analysis by transmission electron microscopy (TEM) demonstrated that exposure to TCS induced morphological changes to synapses and neurons in the hippocampus of offspring. These findings suggested that TCS exposure during lactation contributed to abnormal social behaviors accompanied by increased peripheral inflammation and altered hippocampal neuroplasticity, which provides a deeper understanding of the effects of TCS exposure during early life on brain function and behavioral phenotypes.
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Affiliation(s)
- Ying Hao
- Neuroscience Research Center, Institute of Medical and Health Science, Hebei Medical University, Shijiazhuang 050017, China; Hebei Key laboratory of Neurophysiology, Hebei Medical University, 050017, China
| | - Xiangfei Guo
- Neuroscience Research Center, Institute of Medical and Health Science, Hebei Medical University, Shijiazhuang 050017, China; Hebei Key laboratory of Neurophysiology, Hebei Medical University, 050017, China
| | - Xinhao Wang
- Neuroscience Research Center, Institute of Medical and Health Science, Hebei Medical University, Shijiazhuang 050017, China; Hebei Key laboratory of Neurophysiology, Hebei Medical University, 050017, China
| | - Xiaorui Shi
- Hebei Key laboratory of Neurophysiology, Hebei Medical University, 050017, China; Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Mengxu Shi
- Neuroscience Research Center, Institute of Medical and Health Science, Hebei Medical University, Shijiazhuang 050017, China
| | - Li Meng
- Neuroscience Research Center, Institute of Medical and Health Science, Hebei Medical University, Shijiazhuang 050017, China
| | - Miao Gong
- Hebei Key laboratory of Neurophysiology, Hebei Medical University, 050017, China; Experimental Center for Teaching, Hebei Medical University, Shijiazhuang 050017, China
| | - Yaling Fu
- Neuroscience Research Center, Institute of Medical and Health Science, Hebei Medical University, Shijiazhuang 050017, China; Hebei Key laboratory of Neurophysiology, Hebei Medical University, 050017, China
| | - Ye Zhao
- Neuroscience Research Center, Institute of Medical and Health Science, Hebei Medical University, Shijiazhuang 050017, China; Hebei Key laboratory of Neurophysiology, Hebei Medical University, 050017, China
| | - Yuru Du
- Neuroscience Research Center, Institute of Medical and Health Science, Hebei Medical University, Shijiazhuang 050017, China; Hebei Key laboratory of Neurophysiology, Hebei Medical University, 050017, China
| | - Rui Yang
- Neuroscience Research Center, Institute of Medical and Health Science, Hebei Medical University, Shijiazhuang 050017, China; Hebei Key laboratory of Neurophysiology, Hebei Medical University, 050017, China
| | - Wenshuya Li
- Hebei Key laboratory of Neurophysiology, Hebei Medical University, 050017, China
| | - Kaoqi Lian
- Neuroscience Research Center, Institute of Medical and Health Science, Hebei Medical University, Shijiazhuang 050017, China
| | - Li Song
- Neuroscience Research Center, Institute of Medical and Health Science, Hebei Medical University, Shijiazhuang 050017, China; Hebei Key laboratory of Neurophysiology, Hebei Medical University, 050017, China
| | - Sheng Wang
- Neuroscience Research Center, Institute of Medical and Health Science, Hebei Medical University, Shijiazhuang 050017, China; Hebei Key laboratory of Neurophysiology, Hebei Medical University, 050017, China
| | - Youdong Li
- Neuroscience Research Center, Institute of Medical and Health Science, Hebei Medical University, Shijiazhuang 050017, China
| | - Yun Shi
- Neuroscience Research Center, Institute of Medical and Health Science, Hebei Medical University, Shijiazhuang 050017, China; Department of Biochemistry and Molecular Biology, The Key Laboratory of Neural and Vascular Biology, Ministry of Education of China, Hebei Medical University, Shijiazhuang, Hebei 050017, China.
| | - Haishui Shi
- Neuroscience Research Center, Institute of Medical and Health Science, Hebei Medical University, Shijiazhuang 050017, China; Hebei Key laboratory of Neurophysiology, Hebei Medical University, 050017, China.
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Ågmo A, Laan E. Sexual incentive motivation, sexual behavior, and general arousal: Do rats and humans tell the same story? Neurosci Biobehav Rev 2022; 135:104595. [PMID: 35231490 DOI: 10.1016/j.neubiorev.2022.104595] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 01/28/2022] [Accepted: 02/24/2022] [Indexed: 12/13/2022]
Abstract
Sexual incentive stimuli activate sexual motivation and heighten the level of general arousal. The sexual motive may induce the individual to approach the incentive, and eventually to initiate sexual acts. Both approach and the ensuing copulatory interaction further enhance general arousal. We present data from rodents and humans in support of these assertions. We then suggest that orgasm is experienced when the combined level of excitation surpasses a threshold. In order to analyze the neurobiological bases of sexual motivation, we employ the concept of a central motive state. We then discuss the mechanisms involved in the long- and short-term control of that state as well as those mediating the momentaneous actions of sexual incentive stimuli. This leads to an analysis of the neurobiology behind the interindividual differences in responsivity of the sexual central motive state. Knowledge is still fragmentary, and many contradictory observations have been made. Nevertheless, we conclude that the basic mechanisms of sexual motivation and the role of general arousal are similar in rodents and humans.
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Affiliation(s)
- Anders Ågmo
- Department of Psychology, University of Tromsø, Norway.
| | - Ellen Laan
- Department of Sexology and Psychosomatic Gynaecology, Amsterdam UMC, University of Amsterdam, The Netherlands
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Li D, Li T, Yu J, Liu X, Jia S, Wang X, Wang P, Wang YF. Astrocytic Modulation of Supraoptic Oxytocin Neuronal Activity in Rat Dams with Pup-Deprivation at Different Stages of Lactation. Neurochem Res 2021; 46:2601-2611. [PMID: 32930948 DOI: 10.1007/s11064-020-03129-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 09/05/2020] [Accepted: 09/08/2020] [Indexed: 02/06/2023]
Abstract
Appropriate interactions between astrocytes and oxytocin neurons in the hypothalamo- neurohypophysial system are essential for normal lactation. To further explore the mechanisms underlying astrocytic modulation of oxytocin neuronal activity, we observed astrocytic plasticity in the supraoptic nucleus of lactating rats with intermittent pup-deprivation (PD, 20 h/day) at early (day 1-5) and middle (day 8-12) stages of lactation. PD at both stages decreased suckling duration and litter's body weight gain. They also significantly increased the expression of glial fibrillary acidic protein (GFAP) in Western blots while increased GFAP filaments and the colocalization of GFAP filaments with aquaporin 4 (AQP4) puncta in astrocyte processes surrounding oxytocin neuronal somata in immunohistochemistry in the supraoptic nucleus. Suckling between adjacent milk ejections but not shortly after them decreased molecular association between GFAP and AQP4. In hypothalamic slices from male rats, oxytocin treatment (0.1 nmol/L, 10 min) significantly reduced the length of GFAP filaments and AQP4 puncta in the processes but increased GFAP staining in the somata. These oxytocin effects were blocked by pretreatment of the slices with N-(1,3,4-Thiadiazolyl) nicotinamide (TGN-020, inhibitor of AQP4, 10 µmol/L, 5 min before oxytocin). In addition, inhibition of AQP4 with TGN-020 blocked excitation in oxytocin neurons evoked by prostaglandin E2, a downstream signal of oxytocin receptor and mediator of oxytocin-evoked burst firing, in whole-cell patch-clamp recordings. These results indicate that AQP4-associated astrocytic plasticity is essential for normal oxytocin neuronal activity during lactation and that PD-evoked hypogalactia is associated with astrocytic process expansion following increased GFAP and AQP4 expressions.
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Affiliation(s)
- Dongyang Li
- Department of Physiology, School of Basic Medical Sciences, Harbin Medical University, 157 Baojian Road, Nangang, Harbin, 150081, China
| | - Tong Li
- Department of Physiology, School of Basic Medical Sciences, Harbin Medical University, 157 Baojian Road, Nangang, Harbin, 150081, China
| | - Jiawei Yu
- Department of Physiology, School of Basic Medical Sciences, Harbin Medical University, 157 Baojian Road, Nangang, Harbin, 150081, China
| | - Xiaoyu Liu
- Department of Physiology, School of Basic Medical Sciences, Harbin Medical University, 157 Baojian Road, Nangang, Harbin, 150081, China
| | - Shuwei Jia
- Department of Physiology, School of Basic Medical Sciences, Harbin Medical University, 157 Baojian Road, Nangang, Harbin, 150081, China
| | - Xiaoran Wang
- Department of Physiology, School of Basic Medical Sciences, Harbin Medical University, 157 Baojian Road, Nangang, Harbin, 150081, China
| | - Ping Wang
- Department of Genetics, School of Basic Medical Sciences, Harbin Medical University, Harbin, China
| | - Yu-Feng Wang
- Department of Physiology, School of Basic Medical Sciences, Harbin Medical University, 157 Baojian Road, Nangang, Harbin, 150081, China.
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Oxytocin, Erectile Function and Sexual Behavior: Last Discoveries and Possible Advances. Int J Mol Sci 2021; 22:ijms221910376. [PMID: 34638719 PMCID: PMC8509000 DOI: 10.3390/ijms221910376] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 09/20/2021] [Accepted: 09/23/2021] [Indexed: 12/30/2022] Open
Abstract
A continuously increasing amount of research shows that oxytocin is involved in numerous central functions. Among the functions in which oxytocin is thought to be involved are those that play a role in social and sexual behaviors, and the involvement of central oxytocin in erectile function and sexual behavior was indeed one of the first to be discovered in laboratory animals in the 1980s. The first part of this review summarizes the results of studies done in laboratory animals that support a facilitatory role of oxytocin in male and female sexual behavior and reveal mechanisms through which this ancient neuropeptide participates in concert with other neurotransmitters and neuropeptides in this complex function, which is fundamental for the species reproduction. The second part summarizes the results of studies done mainly with intranasal oxytocin in men and women with the aim to translate the results found in laboratory animals to humans. Unexpectedly, the results of these studies do not appear to confirm the facilitatory role of oxytocin found in male and female sexual behavior in animals, both in men and women. Possible explanations for the failure of oxytocin to improve sexual behavior in men and women and strategies to attempt to overcome this impasse are considered.
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Neural and Hormonal Basis of Opposite-Sex Preference by Chemosensory Signals. Int J Mol Sci 2021; 22:ijms22158311. [PMID: 34361077 PMCID: PMC8347621 DOI: 10.3390/ijms22158311] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 07/28/2021] [Accepted: 07/29/2021] [Indexed: 12/13/2022] Open
Abstract
In mammalian reproduction, sexually active males seek female conspecifics, while estrous females try to approach males. This sex-specific response tendency is called sexual preference. In small rodents, sexual preference cues are mainly chemosensory signals, including pheromones. In this article, we review the physiological mechanisms involved in sexual preference for opposite-sex chemosensory signals in well-studied laboratory rodents, mice, rats, and hamsters of both sexes, especially an overview of peripheral sensory receptors, and hormonal and central regulation. In the hormonal regulation section, we discuss potential rodent brain bisexuality, as it includes neural substrates controlling both masculine and feminine sexual preferences, i.e., masculine preference for female odors and the opposite. In the central regulation section, we show the substantial circuit regulating sexual preference and also the influence of sexual experience that innate attractants activate in the brain reward system to establish the learned attractant. Finally, we review the regulation of sexual preference by neuropeptides, oxytocin, vasopressin, and kisspeptin. Through this review, we clarified the contradictions and deficiencies in our current knowledge on the neuroendocrine regulation of sexual preference and sought to present problems requiring further study.
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Hayashi H, Kumagai R, Kondo Y. Why does castrated male odor attract sexually active male rats?-Attractivity induced by hypothalamus-pituitary-gonad axis block. Physiol Behav 2020; 230:113288. [PMID: 33321143 DOI: 10.1016/j.physbeh.2020.113288] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 12/10/2020] [Accepted: 12/10/2020] [Indexed: 11/16/2022]
Abstract
Sexually experienced male rats show an olfactory preference for estrous female odor compared to male odor. Notably, they also prefer castrated male over gonadally intact male odor. This study examined the role of elevated circulating gonadotropins and gonadotropin-releasing hormone (GnRH) induced by disinhibition of the hypothalamus-pituitary-gonad axis in the castration-induced attractiveness of male rats. Experiment I compared preference of sexually experienced males between odors of castrated males injected with a GnRH antagonist (Cast+Ant), castrated males injected with saline (Cast), and gonadally intact males (Sham). These olfactory preference tests revealed that probe males significantly preferred Cast over Sham and Cast+Ant odors but had no preference between Sham and Cast+Ant odors. Experiment II used hypophysectomy (HPx) to remove the gonadotropin source in place of pharmacologically antagonizing GnRH. Similarly, the probe males preferred Cast (high both GnRH and gonadotropins) over HPx (high GnRH but no gonadotropin) odors, but also preferred HPx than Sham (low both GnRH and gonadotropins) odors. We then examined the effects of exogenous gonadotropins, human chorionic gonadotropin (hCG) and equine chorionic gonadotropin (eCG), to reveal which gonadotropins critically affect on the attractiveness of HPx males. The olfactory preference tests revealed that injecting eCG, but not hCG, significantly increased the probe males` preference compared to HPx male odor, suggesting that the attractiveness is augmented via follicle stimulating hormone (FSH) receptor rather than luteinizing hormone receptor. These results indicate that sexually active male rats show olfactory preference for castrated male rats due to elevated GnRH and FSH blood levels produced by a lack of androgens.
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Affiliation(s)
- Himeka Hayashi
- Department of Animal Sciences, Teikyo University of Science, 2525 Yatsusawa, Uenohara, Yamanashi 409-0193, Japan
| | - Ryoko Kumagai
- Department of Animal Sciences, Teikyo University of Science, 2525 Yatsusawa, Uenohara, Yamanashi 409-0193, Japan
| | - Yasuhiko Kondo
- Department of Animal Sciences, Teikyo University of Science, 2525 Yatsusawa, Uenohara, Yamanashi 409-0193, Japan.
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