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Teruyama R, Govar AA. Role of sexually dimorphic oxytocin receptor-expressing neurons in the anteroventral periventricular nucleus on maternal behavior. Peptides 2024; 180:171283. [PMID: 39142352 DOI: 10.1016/j.peptides.2024.171283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 07/12/2024] [Accepted: 08/11/2024] [Indexed: 08/16/2024]
Abstract
Oxytocin is a neuropeptide produced by magnocellular neurosecretory neurons located primarily in the supraoptic nucleus and paraventricular nucleus of the hypothalamus. The long axons of these neurons project to the neurohypophysis where oxytocin is released into the general circulation in response to the physiological demands. Oxytocin plays critical roles in female reproductive physiology, specifically in uterine contraction during labor and milk ejection while nursing. Oxytocin is also called "the love hormone" due to its modulatory roles in prosocial behaviors, including social recognition, maternal behavior, and pair bonding. Oxytocin influences behaviors by binding to oxytocin receptors (OXTR) located in various parts of the brain. Previously, we discovered a group of estrogen-dependent OXTR neurons that is exclusively present in the anteroventral periventricular nucleus (AVPV) of females but not of males. The female-specific expression of OXTR in the AVPV is a rare case of neurochemically-demonstrated, all-or-none sexual dimorphism in the brain. In this review, the cellular characterization and functional significance of the sexually dimorphic OXTR neurons in the AVPV as well as the clinical implications of the research will be discussed.
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Affiliation(s)
- Ryoichi Teruyama
- Department of Biological Sciences, Louisiana State University, LA, USA.
| | - Armita A Govar
- Department of Biological Sciences, Louisiana State University, LA, USA.
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2
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Higashida H, Oshima Y, Yamamoto Y. Oxytocin transported from the blood across the blood-brain barrier by receptor for advanced glycation end-products (RAGE) affects brain function related to social behavior. Peptides 2024; 178:171230. [PMID: 38677620 DOI: 10.1016/j.peptides.2024.171230] [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: 02/09/2024] [Revised: 04/03/2024] [Accepted: 04/22/2024] [Indexed: 04/29/2024]
Abstract
Oxytocin (OT) is a neuropeptide that primarily functions as a hormone controlling female reproductive processes. Since numerous recent studies have shown that single and repetitive administrations of OT increase trust, social interaction, and maternal behaviors in humans and animals, OT is considered a key molecule that regulates social memory and behavior. Furthermore, OT binds to receptors for advanced glycation end-products (RAGE), and it has been demonstrated that loss of RAGE in the brain vascular endothelial cells of mice fails to increase brain OT concentrations following peripheral OT administration. This leads to the hypothesis that RAGE is involved in the direct transport of OT, allowing it access to the brain by transporting it across the blood-brain barrier; however, this hypothesis is only based on limited evidence. Herein, we review the recent results related to this hypothesis, such as the mode of transport of OT in the blood circulation to the brain via different forms of RAGE, including membrane-bound full-length RAGE and soluble RAGE. We further review the modulation of brain function and social behavior, which seem to be mediated by RAGE-dependent OT. Overall, this review mostly confirms that RAGE enables the recruitment of circulating OT to the brain, thereby influencing social behavior. The requirement for further studies considering the physiological aspects of RAGE is also discussed.
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Affiliation(s)
- Haruhiro Higashida
- Department of Basic Research on Social Recognition and Memory, Research Center for Child Mental Development, Kanazawa University, Kanazawa 920-8640, Japan.
| | - Yu Oshima
- Department of Biochemistry and Molecular Vascular Biology, Kanazawa University Graduate School of Medical Sciences, Kanazawa 920-8640, Japan
| | - Yasuhiko Yamamoto
- Department of Biochemistry and Molecular Vascular Biology, Kanazawa University Graduate School of Medical Sciences, Kanazawa 920-8640, Japan
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Láng T, Dimén D, Oláh S, Puska G, Dobolyi A. Medial preoptic circuits governing instinctive social behaviors. iScience 2024; 27:110296. [PMID: 39055958 PMCID: PMC11269931 DOI: 10.1016/j.isci.2024.110296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/28/2024] Open
Abstract
The medial preoptic area (MPOA) has long been implicated in maternal and male sexual behavior. Modern neuroscience methods have begun to reveal the cellular networks responsible, while also implicating the MPOA in other social behaviors, affiliative social touch, and aggression. The social interactions rely on input from conspecifics whose most important modalities in rodents are olfaction and somatosensation. These inputs bypass the cerebral cortex to reach the MPOA to influence the social function. Hormonal inputs also directly act on MPOA neurons. In turn, the MPOA controls social responses via various projections for reward and motor output. The MPOA thus emerges as one of the major brain centers for instinctive social behavior. While key elements of MPOA circuits have been identified, a synthesis of these new data is now provided for further studies to reveal the mechanisms by which the area controls social interactions.
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Affiliation(s)
- Tamás Láng
- Laboratory of Neuromorphology, Department of Anatomy, Histology and Embryology, Semmelweis University, Budapest, Hungary
| | - Diána Dimén
- Laboratory of Neuromorphology, Department of Anatomy, Histology and Embryology, Semmelweis University, Budapest, Hungary
- Addiction and Neuroplasticity Laboratory, Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, USA
| | - Szilvia Oláh
- Laboratory of Molecular and Systems Neurobiology, Department of Physiology and Neurobiology, Eötvös Loránd University, Budapest, Hungary
| | - Gina Puska
- Laboratory of Molecular and Systems Neurobiology, Department of Physiology and Neurobiology, Eötvös Loránd University, Budapest, Hungary
- Department of Zoology, University of Veterinary Medicine Budapest, Budapest, Hungary
| | - Arpád Dobolyi
- Laboratory of Neuromorphology, Department of Anatomy, Histology and Embryology, Semmelweis University, Budapest, Hungary
- Laboratory of Molecular and Systems Neurobiology, Department of Physiology and Neurobiology, Eötvös Loránd University, Budapest, Hungary
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Sajjaviriya C, Fujianti, Azuma M, Tsuchiya H, Koshimizu TA. Computer vision analysis of mother-infant interaction identified efficient pup retrieval in V1b receptor knockout mice. Peptides 2024; 177:171226. [PMID: 38649033 DOI: 10.1016/j.peptides.2024.171226] [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: 02/17/2024] [Revised: 04/16/2024] [Accepted: 04/18/2024] [Indexed: 04/25/2024]
Abstract
Close contact between lactating rodent mothers and their infants is essential for effective nursing. Whether the mother's effort to retrieve the infants to their nest requires the vasopressin-signaling via V1b receptor has not been fully defined. To address this question, V1b receptor knockout (V1bKO) and control mice were analyzed in pup retrieval test. Because an exploring mother in a new test cage randomly accessed to multiple infants in changing backgrounds over time, a computer vision-based deep learning analysis was applied to continuously calculate the distances between the mother and the infants as a parameter of their relationship. In an open-field, a virgin female V1bKO mice entered fewer times into the center area and moved shorter distances than wild-type (WT). While this behavioral pattern persisted in V1bKO mother, the pup retrieval test demonstrated that total distances between a V1bKO mother and infants came closer in a shorter time than with a WT mother. Moreover, in the medial preoptic area, parts of the V1b receptor transcripts were detected in galanin- and c-fos-positive neurons following maternal stimulation by infants. This research highlights the effectiveness of deep learning analysis in evaluating the mother-infant relationship and the critical role of V1b receptor in pup retrieval during the early lactation phase.
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Affiliation(s)
- Chortip Sajjaviriya
- Division of Molecular Pharmacology, Department of Pharmacology, Jichi Medical University, Tochigi 329-0489, Japan
| | - Fujianti
- Division of Molecular Pharmacology, Department of Pharmacology, Jichi Medical University, Tochigi 329-0489, Japan
| | - Morio Azuma
- Division of Molecular Pharmacology, Department of Pharmacology, Jichi Medical University, Tochigi 329-0489, Japan
| | - Hiroyoshi Tsuchiya
- Division of Molecular Pharmacology, Department of Pharmacology, Jichi Medical University, Tochigi 329-0489, Japan
| | - Taka-Aki Koshimizu
- Division of Molecular Pharmacology, Department of Pharmacology, Jichi Medical University, Tochigi 329-0489, Japan.
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Inada K. Neurobiological mechanisms underlying oxytocin-mediated parental behavior in rodents. Neurosci Res 2024:S0168-0102(24)00052-X. [PMID: 38642676 DOI: 10.1016/j.neures.2024.04.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Revised: 03/29/2024] [Accepted: 04/07/2024] [Indexed: 04/22/2024]
Abstract
Parental behavior is essential for mammalian offspring to survive. Because of this significance, elucidating the neurobiological mechanisms that facilitate parental behavior has received strong interest. Decades of studies utilizing pharmacology and molecular biology have revealed that in addition to its facilitatory effects on parturition and lactation, oxytocin (OT) promotes the expression of parental behavior in rodents. Recent studies have also described the modulation of sensory processing by OT and the interaction of the OT system with other brain regions associated with parental behavior. However, the precise neurobiological mechanisms underlying the facilitation of caregiving behaviors by OT remain unclear. In this Review, I summarize the findings from rats and mice with a view toward integrating past and recent progress. I then review recent advances in the understanding of the molecular, cellular, and circuit mechanisms of OT-mediated parental behavior. Based on these observations, I propose a hypothetical model that would explain the mechanisms underlying OT-mediated parental behavior. Finally, I conclude by discussing some major remaining questions and propose potential future research directions.
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Affiliation(s)
- Kengo Inada
- RIKEN Center for Biosystems Dynamics Research, 2-2-3 Minatojima minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan.
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Kuroda KO, Fukumitsu K, Kurachi T, Ohmura N, Shiraishi Y, Yoshihara C. Parental brain through time: The origin and development of the neural circuit of mammalian parenting. Ann N Y Acad Sci 2024; 1534:24-44. [PMID: 38426943 DOI: 10.1111/nyas.15111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2024]
Abstract
This review consolidates current knowledge on mammalian parental care, focusing on its neural mechanisms, evolutionary origins, and derivatives. Neurobiological studies have identified specific neurons in the medial preoptic area as crucial for parental care. Unexpectedly, these neurons are characterized by the expression of molecules signaling satiety, such as calcitonin receptor and BRS3, and overlap with neurons involved in the reproductive behaviors of males but not females. A synthesis of comparative ecology and paleontology suggests an evolutionary scenario for mammalian parental care, possibly stemming from male-biased guarding of offspring in basal vertebrates. The terrestrial transition of tetrapods led to prolonged egg retention in females and the emergence of amniotes, skewing care toward females. The nocturnal adaptation of Mesozoic mammalian ancestors reinforced maternal care for lactation and thermal regulation via endothermy, potentially introducing metabolic gate control in parenting neurons. The established maternal care may have served as the precursor for paternal and cooperative care in mammals and also fostered the development of group living, which may have further contributed to the emergence of empathy and altruism. These evolution-informed working hypotheses require empirical validation, yet they offer promising avenues to investigate the neural underpinnings of mammalian social behaviors.
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Affiliation(s)
- Kumi O Kuroda
- RIKEN Center for Brain Science, Saitama, Japan
- School of Life Sciences and Technologies, Tokyo Institute of Technology, Kanagawa, Japan
| | - Kansai Fukumitsu
- RIKEN Center for Brain Science, Saitama, Japan
- Department of Physiology, Fujita Health University School of Medicine, Toyoake, Japan
| | - Takuma Kurachi
- RIKEN Center for Brain Science, Saitama, Japan
- Department of Agriculture, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Nami Ohmura
- RIKEN Center for Brain Science, Saitama, Japan
- Center for Brain, Mind and Kansei Sciences Research, Hiroshima University, Hiroshima, Japan
| | - Yuko Shiraishi
- RIKEN Center for Brain Science, Saitama, Japan
- Kawamura Gakuen Woman's University, Chiba, Japan
| | - Chihiro Yoshihara
- RIKEN Center for Brain Science, Saitama, Japan
- School of Life Sciences and Technologies, Tokyo Institute of Technology, Kanagawa, Japan
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Kurachi T, Shinozuka K, Yoshihara C, Yano-Nashimoto S, Murayama AY, Hata J, Haga Y, Okano H, Kuroda KO. Distinct roles of amylin and oxytocin signaling in intrafamilial social behaviors at the medial preoptic area of common marmosets. Commun Biol 2023; 6:1231. [PMID: 38052969 PMCID: PMC10698028 DOI: 10.1038/s42003-023-05593-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Accepted: 11/15/2023] [Indexed: 12/07/2023] Open
Abstract
Calcitonin receptor (Calcr) and its brain ligand amylin in the medial preoptic area (MPOA) are found to be critically involved in infant care and social contact behaviors in mice. In primates, however, the evidence is limited to an excitotoxic lesion study of the Calcr-expressing MPOA subregion (cMPOA) in a family-living primate species, the common marmoset. The present study utilized pharmacological manipulations of the cMPOA and shows that reversible inactivation of the cMPOA abolishes infant-care behaviors in sibling marmosets without affecting other social or non-social behaviors. Amylin-expressing neurons in the marmoset MPOA are distributed in the vicinity of oxytocin neurons in the anterior paraventricular nucleus of the hypothalamus. While amylin infusion facilitates infant carrying selectively, an oxytocin's inverse agonist, atosiban, reduces physical contact with non-infant family members without grossly affecting infant care. These data suggest that the amylin and oxytocin signaling mediate intrafamilial social interactions in a complementary manner in marmosets.
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Affiliation(s)
- Takuma Kurachi
- Laboratory for Affiliative Social Behavior, RIKEN Center for Brain Science, Saitama, Japan
- Department of Agriculture, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Kazutaka Shinozuka
- Laboratory for Affiliative Social Behavior, RIKEN Center for Brain Science, Saitama, Japan
| | - Chihiro Yoshihara
- Laboratory for Affiliative Social Behavior, RIKEN Center for Brain Science, Saitama, Japan
- School of Life Science and Technology, Tokyo Institute of Technology, Kanagawa, Japan
| | - Saori Yano-Nashimoto
- Laboratory for Affiliative Social Behavior, RIKEN Center for Brain Science, Saitama, Japan
- Laboratory of Physiology, Department of Basic Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Hokkaido, Japan
| | - Ayako Y Murayama
- Laboratory for Affiliative Social Behavior, RIKEN Center for Brain Science, Saitama, Japan
- Department of Physiology, Keio University School of Medicine, Tokyo, Japan
| | - Junichi Hata
- Department of Physiology, Keio University School of Medicine, Tokyo, Japan
- Laboratory for Marmoset Neural Architecture, RIKEN Center for Brain Science, Saitama, Japan
- Graduate School of Human Health Sciences, Tokyo Metropolitan University, Arakawa, Tokyo, Japan
| | - Yawara Haga
- Laboratory for Marmoset Neural Architecture, RIKEN Center for Brain Science, Saitama, Japan
| | - Hideyuki Okano
- Department of Physiology, Keio University School of Medicine, Tokyo, Japan
- Laboratory for Marmoset Neural Architecture, RIKEN Center for Brain Science, Saitama, Japan
| | - Kumi O Kuroda
- Laboratory for Affiliative Social Behavior, RIKEN Center for Brain Science, Saitama, Japan.
- School of Life Science and Technology, Tokyo Institute of Technology, Kanagawa, Japan.
- Laboratory for Circuit and Behavioral Physiology, RIKEN Center for Brain Science, Saitama, Japan.
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Ohmura N, Okuma L, Truzzi A, Esposito G, Kuroda KO. Maternal physiological calming responses to infant suckling at the breast. J Physiol Sci 2023; 73:3. [PMID: 36918820 DOI: 10.1186/s12576-023-00860-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 03/02/2023] [Indexed: 03/16/2023]
Abstract
The mother-infant relation is key to infant physical, cognitive and social development. Mutual regulation and cooperation are required to maintain the dyadic system, but the biological foundation of these responses remains to be clarified. In this study, we report the maternal calming responses to infant suckling during breastfeeding. Using behavioral measures and a Holter electrocardiogram as a readout of the maternal autonomic nervous system, the maternal activities during resting, sitting with her infant on her lap, and breastfeeding were assessed. We found that during breastfeeding, mothers talked less and maternal heart rate was lower than during sitting with the infant without breastfeeding. Congruently, maternal heart rate variability measurements indicated a higher parasympathetic activity during breastfeeding. Time-locked analyses suggested that this maternal calming response was initiated by the tactile stimulation at the breast by the infant face or mouth latch, which preceded the perceived milk ejection. These findings suggest that somatosensory stimuli of breastfeeding activate parasympathetic activity in mothers. Just as how the infant Transport Response facilitates the carrying of infants, the maternal calming responses during breastfeeding may promote efficient milk intake by inhibiting spontaneous maternal activities.
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Affiliation(s)
- Nami Ohmura
- Laboratory for Affiliative Social Behavior, RIKEN Center for Brain Science, 351-0198, Saitama, Japan.
| | - Lana Okuma
- Laboratory for Affiliative Social Behavior, RIKEN Center for Brain Science, 351-0198, Saitama, Japan.,Laboratory for Human Cognition and Learning, RIKEN Center for Brain Science, Saitama, 351-0198, Japan
| | - Anna Truzzi
- Department of Psychology and Cognitive Science, University of Trento, Rovereto, TN, Italy.,School of Psychology, Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin, Ireland
| | - Gianluca Esposito
- Department of Psychology and Cognitive Science, University of Trento, Rovereto, TN, Italy
| | - Kumi O Kuroda
- Laboratory for Affiliative Social Behavior, RIKEN Center for Brain Science, 351-0198, Saitama, Japan.
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Gigliucci V, Busnelli M, Santini F, Paolini C, Bertoni A, Schaller F, Muscatelli F, Chini B. Oxytocin receptors in the Magel2 mouse model of autism: Specific region, age, sex and oxytocin treatment effects. Front Neurosci 2023; 17:1026939. [PMID: 36998737 PMCID: PMC10043208 DOI: 10.3389/fnins.2023.1026939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 02/20/2023] [Indexed: 03/16/2023] Open
Abstract
The neurohormone oxytocin (OXT) has been implicated in the regulation of social behavior and is intensively investigated as a potential therapeutic treatment in neurodevelopmental disorders characterized by social deficits. In the Magel2-knockout (KO) mouse, a model of Schaaf-Yang Syndrome, an early postnatal administration of OXT rescued autistic-like behavior and cognition at adulthood, making this model relevant for understanding the actions of OXT in (re)programming postnatal brain development. The oxytocin receptor (OXTR), the main brain target of OXT, was dysregulated in the hippocampus of Magel2-KO adult males, and normalized upon OXT treatment at birth. Here we have analyzed male and female Magel2-KO brains at postnatal day 8 (P8) and at postnatal day 90 (P90), investigating age, genotype and OXT treatment effects on OXTR levels in several regions of the brain. We found that, at P8, male and female Magel2-KOs displayed a widespread, substantial, down-regulation of OXTR levels compared to wild type (WT) animals. Most intriguingly, the postnatal OXT treatment did not affect Magel2-KO OXTR levels at P8 and, consistently, did not rescue the ultrasonic vocalization deficits observed at this age. On the contrary, the postnatal OXT treatment reduced OXTR levels at P90 in male Magel2-KO in a region-specific way, restoring normal OXTR levels in regions where the Magel2-KO OXTR was upregulated (central amygdala, hippocampus and piriform cortex). Interestingly, Magel2-KO females, previously shown to lack the social deficits observed in Magel2-KO males, were characterized by a different trend in receptor expression compared to males; as a result, the dimorphic expression of OXTR observed in WT animals, with higher OXTR expression observed in females, was abolished in Magel2-KO mice. In conclusion, our data indicate that in Magel2-KO mice, OXTRs undergo region-specific modifications related to age, sex and postnatal OXT treatment. These results are instrumental to design precisely-timed OXT-based therapeutic strategies that, by acting at specific brain regions, could modify the outcome of social deficits in Schaaf-Yang Syndrome patients.
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Affiliation(s)
- Valentina Gigliucci
- Institute of Neuroscience, National Research Council, Vedano al Lambro, Italy
- NeuroMI Milan Center for Neuroscience, University of Milano-Bicocca, Milan, Italy
| | - Marta Busnelli
- Institute of Neuroscience, National Research Council, Vedano al Lambro, Italy
- NeuroMI Milan Center for Neuroscience, University of Milano-Bicocca, Milan, Italy
| | - Francesca Santini
- Institute of Neuroscience, National Research Council, Vedano al Lambro, Italy
- NeuroMI Milan Center for Neuroscience, University of Milano-Bicocca, Milan, Italy
- Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, Milan, Italy
| | - Camilla Paolini
- Institute of Neuroscience, National Research Council, Vedano al Lambro, Italy
- NeuroMI Milan Center for Neuroscience, University of Milano-Bicocca, Milan, Italy
| | | | | | | | - Bice Chini
- Institute of Neuroscience, National Research Council, Vedano al Lambro, Italy
- NeuroMI Milan Center for Neuroscience, University of Milano-Bicocca, Milan, Italy
- *Correspondence: Bice Chini,
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Hagihara M, Miyamichi K, Inada K. The importance of oxytocin neurons in the supraoptic nucleus for breastfeeding in mice. PLoS One 2023; 18:e0283152. [PMID: 36930664 PMCID: PMC10022762 DOI: 10.1371/journal.pone.0283152] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Accepted: 03/02/2023] [Indexed: 03/18/2023] Open
Abstract
The hormone oxytocin, secreted from oxytocin neurons in the paraventricular (PVH) and supraoptic (SO) hypothalamic nuclei, promotes parturition, milk ejection, and maternal caregiving behaviors. Previous experiments with whole-body oxytocin knockout mice showed that milk ejection was the unequivocal function of oxytocin, whereas parturition and maternal behaviors were less dependent on oxytocin. Whole-body knockout, however, could induce the enhancement of expression of related gene(s), a phenomenon called genetic compensation, which may hide the actual functions of oxytocin. In addition, the relative contributions of oxytocin neurons in the PVH and SO have not been well documented. Here, we show that females with conditional knockout of oxytocin gene in both the PVH and SO undergo grossly normal parturition and maternal caregiving behaviors, while dams with a smaller number of remaining oxytocin-expressing neurons exhibit severe impairments in breastfeeding, leading to the death of their pups within 24 hours after birth. We also found that the growth of pups is normal even under oxytocin conditional knockout in PVH and SO as long as pups survive the next day of delivery, suggesting that the reduced oxytocin release affects the onset of lactation most severely. These phenotypes are largely recapitulated by SO-specific oxytocin conditional knockout, indicating the unequivocal role of oxytocin neurons in the SO in successful breastfeeding. Given that oxytocin neurons not only secrete oxytocin but also non-oxytocin neurotransmitters or neuropeptides, we further performed cell ablation of oxytocin neurons in the PVH and SO. We found that cell ablation of oxytocin neurons leads to no additional abnormalities over the oxytocin conditional knockout, suggesting that non-oxytocin ligands expressed by oxytocin neurons have negligible functions on the responses measured in this study. Collectively, our findings confirm the dispensability of oxytocin for parturition or maternal behaviors, as well as the importance of SO-derived oxytocin for breastfeeding.
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Affiliation(s)
- Mitsue Hagihara
- RIKEN Center for Biosystems Dynamics Research, Chuo-ku, Kobe, Hyogo, Japan
| | - Kazunari Miyamichi
- RIKEN Center for Biosystems Dynamics Research, Chuo-ku, Kobe, Hyogo, Japan
- * E-mail: (KI); (KM)
| | - Kengo Inada
- RIKEN Center for Biosystems Dynamics Research, Chuo-ku, Kobe, Hyogo, Japan
- * E-mail: (KI); (KM)
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11
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Inada K, Hagihara M, Tsujimoto K, Abe T, Konno A, Hirai H, Kiyonari H, Miyamichi K. Plasticity of neural connections underlying oxytocin-mediated parental behaviors of male mice. Neuron 2022; 110:2009-2023.e5. [PMID: 35443152 DOI: 10.1016/j.neuron.2022.03.033] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 03/04/2022] [Accepted: 03/28/2022] [Indexed: 11/15/2022]
Abstract
The adult brain can flexibly adapt behaviors to specific life-stage demands. For example, while sexually naive male mice are aggressive to the conspecific young, they start to provide caregiving to infants around the time when their own young are expected. How such behavioral plasticity is implemented at the level of neural connections remains poorly understood. Here, using viral-genetic approaches, we establish hypothalamic oxytocin neurons as the key regulators of the parental caregiving behaviors of male mice. We then use rabies-virus-mediated unbiased screening to identify excitatory neural connections originating from the lateral hypothalamus to the oxytocin neurons to be drastically strengthened when male mice become fathers. These connections are functionally relevant, as their activation suppresses pup-directed aggression in virgin males. These results demonstrate the life-stage associated, long-distance, and cell-type-specific plasticity of neural connections in the hypothalamus, the brain region that is classically assumed to be hard-wired.
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Affiliation(s)
- Kengo Inada
- Laboratory for Comparative Connectomics, RIKEN Center for Biosystems Dynamics Research, Kobe, Hyogo 650-0047, Japan.
| | - Mitsue Hagihara
- Laboratory for Comparative Connectomics, RIKEN Center for Biosystems Dynamics Research, Kobe, Hyogo 650-0047, Japan
| | - Kazuko Tsujimoto
- Laboratory for Comparative Connectomics, RIKEN Center for Biosystems Dynamics Research, Kobe, Hyogo 650-0047, Japan
| | - Takaya Abe
- Laboratory for Animal Resources and Genetic Engineering, RIKEN Center for Biosystems Dynamics Research, Kobe, Hyogo 650-0047, Japan
| | - Ayumu Konno
- Gunma University Graduate School of Medicine, Maebashi, Gunma 371-8511, Japan; Viral Vector Core, Gunma University Initiative for Advanced Research (GIAR), Maebashi, Gunma 371-8511, Japan
| | - Hirokazu Hirai
- Gunma University Graduate School of Medicine, Maebashi, Gunma 371-8511, Japan; Viral Vector Core, Gunma University Initiative for Advanced Research (GIAR), Maebashi, Gunma 371-8511, Japan
| | - Hiroshi Kiyonari
- Laboratory for Animal Resources and Genetic Engineering, RIKEN Center for Biosystems Dynamics Research, Kobe, Hyogo 650-0047, Japan
| | - Kazunari Miyamichi
- Laboratory for Comparative Connectomics, RIKEN Center for Biosystems Dynamics Research, Kobe, Hyogo 650-0047, Japan; Japan Science and Technology Agency, PRESTO, Kawaguchi, Saitama 332-0012, Japan.
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