一般口演（若手道場）

一般口演（若手道場）若手道場　神経内分泌と行動 Wakate Dojo: Neuroendocrine System and Behavior 座長：竹本ー木村さやか（名古屋大学）・南雅文（北海道大学）

2022年6月30日　15:00～15:15　沖縄コンベンションセンター会議場A2　第7会場 1WD07a2-01 父性養育行動におけるバソトシンーオキシトシン受容体シグナル伝達 A vasotocin-to-oxytocin receptor signaling underlies paternal caregiving behaviors 稲田健吾(1)、萩原光恵(1)、宮道和成(1) 1. 理化学研究所生命機能科学研究センター Kengo Inada(1), Mitsue Hagihara(1), Kazunari Miyamichi(1) 1. Center for Biosystems Dynamics Research, RIKEN Keyword: Oxytocin receptor , Parental behavior, Vasotocin Mammalian parents provide caregiving behaviors to their infants. In rodents, the expression of parental behaviors is, in part, regulated by hypothalamic neuropeptides. Oxytocin (OT) and vasotocin (VT; previously known as vasopressin) are neuropeptides known to evoke parental behaviors. Although they are synthesized in and secreted from the different populations of neurons, OT and VT differ by only two amino acid residues. Both OT and VP can activate each other’s canonical receptor, OT receptors (OTRs) and VT receptors (VTRs), a phenomenon known as receptor crosstalk. Owing to these features, our understanding of the OT/VT-mediated parental behaviors is still limited. Here we show that at the downstream circuits, OT/VT-derived expression of parental behaviors is mediated through receptor crosstalk. We focused on the OT and VT neurons in the paraventricular hypothalamic nucleus (PVH) of virgin male mice. Chemogenetic activation of PVH OT or VT neurons inhibited pup-directed aggression and promoted parental behaviors in virgin males. To analyze which type of receptors is critically mediate OT/VT-derived parental behaviors, we applied selective antagonists for OTRs or VTRs into the ventricle, while chemogenetically activating OT or VT neurons. We found that application of the OTR antagonist resumed pup-directed aggression, suggesting that OTRs are important for the suppression of pup-directed aggression not only under the activation of OT neurons but also when VT neurons were activated. To confirm whether inhibition of pup-directed aggression by chemogenetic activation of VT neurons requires OTRs, next we employed the combination of viral and genetic methods: conditional knockout of OTRs by injecting an adeno-associated virus that drives Cre expression. Viral spreading was restricted to several nuclei, enabling the identification of brain regions in which OTRs mediate the suppression of pup-directed aggression. We found that males with conditional knockout of OTRs in the “anterior hypothalamus”, mainly including the anteroventral periventricular nucleus (AVPV) and medial preoptic nucleus (MPN), showed pup-directed aggression even under the chemogenetic activation of VT neurons. Taken together, these results suggest that OTR signaling in the anterior part of the hypothalamus is important for the expression of parental behaviors evoked by both OT neurons and VT neurons.		2022年6月30日　15:15～15:30　沖縄コンベンションセンター会議場A2　第7会場 1WD07a2-02 観察恐怖タスクにおける、内側前頭前野での多面的な行動情報の神経表象 Neural representation of multifaceted behavioral states during observational fear in the medial prefrontal cortex 黄子彦(1,2)、田尾賢太郎(1)、Myung Chung(1,2)、度会晃行(1)、王牧芸(1)、伊藤広朗(3)、奥山輝大(1) 1. 東京大学定量生命科学研究所、2. 東京大学大学院医学系研究科、3. 東京大学理学部 Ziyan Huang(1,2), Kentaro Tao(1), Myung Chung(1,2), Akiyuki Watarai(1), Mu-Yun Wang(1), Hiroh Ito(3), Teruhiro Okuyama(1) 1. IQB, Univ of Tokyo, Tokyo, Japan, 2. Grad Sch Med, Univ of Tokyo, Tokyo, Japan, 3. Sch Sci, Univ of Tokyo, Tokyo, Japan Keyword: OBSERVATIONAL FEAR, MEDIAL PREFRONTAL CORTEX, IN VIVO CALCIUM IMAGING, ANIMAL TRACKING Emotional contagion of fear as a fundamental form of empathy is observed across species through social observation of others suffering from aversive stimuli. Observational fear (OF) task in rodents enables quantification of the vicarious fear response of an observer by assessing freezing, while a demonstrator receives repetitive foot shocks. Although the observer exhibits complex behaviors, including approaching and gazing, as well as freezing, it remains unclear how these multifaceted behavioral states are neurophysiologically represented during observational fear. Here, by combining deep-learning-based behavioral tracking (DeepLabCut) and dimension reduction clustering using t-distributed stochastic neighbor embedding (t-SNE), we classified eight types of stereotypical behavioral clusters. As for neural mechanisms, human fMRI studies have shown that the anterior cingulate cortex and amygdala are involved, and their functions have been demonstrated in rodent studies to be socially derived fear acquisition and recall, respectively. However, although the involvement of the medial prefrontal cortex (mPFC) was also implied by human fMRI studies, its pivotal role has not been clarified using rodents. Here, optogenetic inhibition of the medial prefrontal cortex (mPFC) disrupted the appropriate behavioral transitions and active avoidance behavior of observer mice during the task. Furthermore, in vivo microendoscopic Ca²⁺ imaging revealed that the multifaceted information on behavioral clusters, their transition, and freezing was encoded and intermingled in the mPFC neuronal populations. Our study suggests that the mPFC, a central hub of the social brain, monitors and adjusts the multifaceted behavioral states of self in social situations.

2022年6月30日　15:30～15:45　沖縄コンベンションセンター会議場A2　第7会場 1WD07a2-03 エストロゲン受容体2bはメダカの性行動パターンのメス化と脱オス化を司る Estrogen receptor 2b is responsible for feminization and demasculinization of mating behavior in medaka 西池雄志(1)、大久保範聡(1) 1. 東京大学大学院農学生命科学研究科 Yuji Nishiike(1), Kataaki Okubo(1) 1. Grad Sch Agric Life Sci, Univ of Tokyo, Tokyo, Japan Keyword: estrogen receptor, mating behaviors, sexual reversal, teleost Male and female animals typically display sex-specific mating behaviors; in general, males exhibit courtship displays to females and females evaluate male suitability. Such sex-specific mating behaviors are the result of sexually distinct neural mechanisms, which, in vertebrates, are highly dependent on sex steroids. In mammals and birds, perinatal sex steroids act during early critical periods to irreversibly organize the neural substrate that later mediates mating behavior; as such, these species show little sexual plasticity in mating behaviors in adulthood. On the contrary, the teleost brain remains sexually labile into adulthood and instead the adult sex steroid milieu is the major determinant of sex-typical mating behavior, which allows for the sex reversal of mating behaviors, even after maturation. However, only limited information is available on how sex steroids regulate the neural substrates governing mating behavior in teleosts. In medaka (Oryzias latipes), estrogen receptor 2b (Esr2b) is expressed in telencephalic and preoptic nuclei implicated in mating behavior in a female-specific manner. This observation prompted us to investigate the function of Esr2b in female mating behavior. Our data revealed that esr2b-deficient females are unreceptive to male courtship and instead exhibit male-typical mating behaviors towards females. Additionally, esr2b-deficient females showed no alteration in their sex steroid milieu or disruption ovarian function, which suggests that the loss of Estrogen/Esr2b signaling in the brain is responsible for this phenotype. Our results also showed that the female-bias in esr2b expression in mating behavior-related brain regions can be reversed between males and females by altering the adult sex steroid milieu. Collectively, these data indicate that the adult sex steroid milieu which determines sex-typical mating behaviors acts, presumably, by regulating the expression of esr2b, which has an essential role in establishing the neural circuits responsible for female mating behaviors. Such neural mechanisms may underpin sexual lability in mating behavior across teleost species.		2022年6月30日　15:45～16:00　沖縄コンベンションセンター会議場A2　第7会場 1WD07a2-04 PVH TH ニューロンは摂食行動を仲介します PVH TH neurons mediate feeding behaviors Ariyani Winda(1)、常岡明加(1,2)、吉川千遥(1)、一瀬宏(3)、北村忠弘(1)、河野大輔(1) 1. 群馬大学生体調節研究所代謝シグナル解析分野、2. 群馬大学医学系研究科脳神経外科、3. 東京工業大学, 生命理工学院 WINDA ARIYANI(1), Haruka Tsuneoka(1,2), Chiharu Yoshikawa(1), Hiroshi Ichinose(3), Tadahiro Kitamura(1), Daisuke Kohno(1) 1. Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Japan, 2. Department of Neurosurgery, Gunma University Graduate School of Medicine, Maebashi, Japan., 3. School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan. Keyword: Dnmt3a, tyrosine hydroxylase, feeding behavior, dopamine The paraventricular hypothalamus (PVH) plays a vital role in feeding regulation. Our previous study showed that the deletion of DNA methyltransferase 3a (DNMT3a) in the PVH (Dnmt3a^lox/lox/Sim1-Cre) highly increases the tyrosine hydroxylase (TH) expression level in the PVH and induced obesity. This study explored the role and characteristics of TH positive neurons in the PVH in the context of feeding behavior. Consistent with our previous study, PVH specific Dnmt3a knockout mice (Dnmt3a^lox/lox/Sim1-Cre) increased body weight. On the other hand, the bodyweight of PVH specific Dnmt3a and Th double knockout mice (Dnmt3a^lox/lox/Th^lox/lox/Sim1-Cre) was not different from control mice (Dnmt3a^lox/lox/Th^lox/lox). Food intake, oxygen consumption, respiratory exchange ratio, and locomotor activity of Dnmt3a^lox/lox/Th^lox/lox/Sim1-Cre mice were comparable to the control mice, suggesting that the feeding and metabolic phenotypes of Dnmt3a knockout mice were disappeared in the Dnmt3a and Th double knockout mice. The PVH specific Th knockout mice (Th^lox/lox/Sim1-Cre) did not show the difference in body weight, oxygen consumption, and respiratory exchange ratio compared to control mice (Th^lox/lox). However, Th^lox/lox/Sim1-Cre mice had different feeding patterns. In addition, Th^lox/lox/Sim1-Cre mice had higher locomotor activity during the dark period. Immunohistochemistry analysis showed that TH neurons in PVH were surrounded by NPY and POMC fibers. Moreover, TH neurons were highly colocalized with DAT and GAD67. These results suggest that TH neurons in PVH are dopaminergic/GABAergic neurons part of the melanocortin pathway and play an important role in controlling feeding behavior.