担当区分：筆頭著者   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japan Society of Histochemistry & Cytochemistry  

DOI： 10.1267/ahc.22-00043

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

The suprachiasmatic nucleus (SCN) of the hypothalamus is a nucleus that regulates circadian rhythms through the cyclic expression of clock genes. It has been suggested that circadian-rhythm-related, adverse postoperative events, including sleep disturbances and delirium, are partly caused by anesthesia-induced disruption of clock-gene expression. We examined the effects of multiple general anesthetics on the expression cycle of Period2 (Per2), one of the clock genes that regulate circadian rhythms in the SCN, and on the behavioral rhythms of animals. Rats were treated with sevoflurane, propofol, and dexmedetomidine for 4 h. The expression of Per2 in SCN was analyzed using in situ hybridization, and the behavioral rhythm before and after anesthesia was analyzed. Per2 expression in the SCN decreased significantly immediately after anesthesia in all groups compared with corresponding control groups. However, Per2 returned to normal levels within 24 h, and there was no phase change in the gene expression cycle or behavioral rhythm. This study suggests that acute suppression of Per2 expression may be a general phenomenon induced by general anesthesia, but that the molecular mechanism of the body clock is resilient to disturbances to some extent.

DOI： 10.1007/s00418-022-02113-0

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

General anesthetics have different efficacies and side effect incidences based on their mechanism of action. However, detailed comparative studies of anesthetics are incomplete. In this study, target brain regions and gene expression changes in these brain regions were determined for sevoflurane and propofol to understand the mechanisms that cause differences among anesthetics. Rats were anesthetized with sevoflurane or propofol for 1 hr, and brain regions with anesthesia-induced changes in neuronal activity were examined by immunohistochemistry and in situ hybridization for c-Fos. Among the identified target brain regions, gene expression analysis was performed in the habenula, the solitary nucleus and the medial vestibular nucleus from laser microdissected samples. Genes altered by sevoflurane and propofol were different and included genes involved in the incidence of postoperative nausea and vomiting and emergence agitation, such as Egr1 and Gad2. GO enrichment analysis showed that the altered genes tended to be evenly distributed in all functional category. The detailed profiles of target brain regions and induced gene expression changes of sevoflurane and propofol in this study will provide a basis for analyzing the effects of each anesthetic agent and the risk of adverse events.

DOI： 10.1267/ahc.21-00091

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Although there are few well-validated antibodies against ESR2 proteins, a recent validation assessment identified a specific monoclonal antibody against human ESR2 proteins (PPZ0506). Furthermore, our previous study confirmed its cross-reactivity and specificity against rodent ESR2 proteins, enabling the determination of true ESR2 distribution profiles in rodents. Therefore, we aimed to determine optimal conditions for ESR2 detection by PPZ0506 immunostaining and analyze ESR2 distribution in rats. We evaluated several staining conditions using paraffin-embedded and frozen ovary sections. Immunohistochemical staining with PPZ0506 antibody required strong antigen retrieval and appropriate antibody dilution. Subsequent immunohistochemical analysis in multiple tissues under optimized conditions revealed that rat ESR2 proteins are expressed in a more localized manner than previously assumed. Our results suggest that previous immunohistochemical studies using inadequately validated antibodies against ESR2 proteins overestimated their distribution profiles. We expect that optimized immunohistochemical detection with PPZ0506 antibody can help researchers solve several conflicting problems in ESR2 research.

DOI： 10.1016/j.mce.2020.111145

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

RF-amide peptides, a family of peptides characterized by a common carboxy-terminal Arg-Phe-NH2 motif, play various physiological roles in the brain including the modulation of neuroendocrine signaling. Neuropeptide FF (NPFF) receptors exhibit a high affinity for all RF-amide peptides, which suggests that the neurons expressing these NPFF receptors may have multiple functions in the brain. However, the distribution of the neurons expressing NPFF receptors in the rat brain remains poorly understood. This study aimed to determine the detailed histological distribution of mRNA that encodes the neuropeptide FF receptors (Npffr1 and Npffr2) in the rat brain using in situ hybridization. Neurons with strong Npffr1 expression were observed in the lateral septal nucleus and several hypothalamic areas related to neuroendocrine functions, including the paraventricular nucleus (PVN) and arcuate nucleus, whereas Npffr2-expressing neurons were observed mainly in brain regions involved in somatosensory pathways, such as several subnuclei of the thalamus. Npffr1 expression was observed in 70% of corticotropin-releasing hormone neurons, but in only a small population of oxytocin and vasopressin neurons in the PVN. Npffr1 expression was also observed in the dopaminergic neurons in the periventricular nucleus and the dorsal arcuate nucleus, and in the kisspeptin neurons in the anteroventral periventricular nucleus. These results suggest that NPFFR1-mediated signaling may be involved in neuroendocrine functions, such as in reproduction and stress response. In conjunction with a detailed histological map of NPFFRs, this study provides useful data for future neuroendocrine research.

DOI： 10.1007/s00418-020-01956-9

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記述言語：日本語   出版者・発行元：日本医科大学医学会  

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記述言語：英語  

Estrogens play an essential role in multiple physiological functions in the brain, including reproductive neuroendocrine, learning and memory, and anxiety-related behaviors. To determine these estrogen functions, many studies have tried to characterize neurons expressing estrogen receptors known as ERα and ERβ. However, the characteristics of ERβ-expressing neurons in the rat brain still remain poorly understood compared to that of ERα-expressing neurons. The main aim of this study is to determine the neurochemical characteristics of ERβ-expressing neurons in the rat hypothalamus using RNAscope in situ hybridization (ISH) combined with immunofluorescence. Strong Esr2 signals were observed especially in the anteroventral periventricular nucleus (AVPV), bed nucleus of stria terminalis, hypothalamic paraventricular nucleus (PVN), supraoptic nucleus, and medial amygdala, as previously reported. RNAscope ISH with immunofluorescence revealed that more than half of kisspeptin neurons in female AVPV expressed Esr2, whereas few kisspeptin neurons were found to co-express Esr2 in the arcuate nucleus. In the PVN, we observed a high ratio of Esr2 co-expression in arginine-vasopressin neurons and a low ratio in oxytocin and corticotropin-releasing factor neurons. The detailed neurochemical characteristics of ERβ-expressing neurons identified in the current study can be very essential to understand the estrogen signaling via ERβ.

DOI： 10.3390/ijms21010115

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.3390/ijms20246312

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その他リンク： http://orcid.org/0000-0003-2044-316X

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s00418-018-01767-z

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：SAGE PUBLICATIONS INC  

Objective. Autophagy was reported to be essential for maintaining chondrocyte function, and reduced autophagy leads to osteoarthritis (OA). Previous studies showed involvement of heat shock stress in the control of autophagy in cells. This study sought to investigate the effect of hyperthermia on the expression of autophagy-related proteins in articular cartilage and the progression of naturally occurring OA in Hartley guinea pigs. Design.Radiofrequency pulses of 13.56 MHz were applied to the animals' knees for 20 minutes to induce hyperthermia. The knee joints were resected at 8 hours, 24 hours, 72 hours, 7 days, and 6 months after hyperthermia. Serial sections of knees were examined for histopathological changes. The expression levels of Unc-51-like kinase 1 (ULK1) and Beclin1 were analyzed by immunohistochemistry.Results. Analysis of the distribution of positive cells showed that, in cases of moderate OA, ULK1 and Beclin1 expression levels were significantly decreased in the superficial zone (SZ) and middle zone (MZ) (P < 0.01) compared with normal cartilage. Seven days after exposure to radiofrequency waves, expression levels of ULK1 and Beclin1 were augmented in the SZ in animals with mild OA. The severity of cartilage degradation was significantly reduced (P < 0.01) in the radiofrequency-treated knees versus the untreated knees.Conclusions. This study showed that heat stimulation enhanced autophagy in healthy knee chondrocytes and chondrocytes in knees with mild OA. The study also showed that long-term periodic application of hyperthermia suppresses aging-related progression of OA. The activation of autophagy by radiofrequency hyperthermia may be an effective therapeutic approach for osteoarthritis.

DOI： 10.1177/1947603516678974

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：WILEY  

Kisspeptin is essential in reproduction and acts by stimulating neurones expressing gonadotrophin- releasing hormone (GnRH). Recent studies suggest that kisspeptin has multiple roles in the modulation of neuronal circuits in systems outside the hypothalamic-pituitary-gonadal axis. Our recent research using in situ hybridisation (ISH) clarified the histological distribution of Kiss1r (Gpr54)-expressing neurones in the rat brain that were presumed to be putative targets of kisspeptin. The arcuate nucleus (ARN) of the hypothalamus is one of the brain regions in which Kiss1r expression in non-GnRH neurones is prominent. However, the characteristics of Kiss1rexpressing neurones in the ARN remain unclear. The present study aimed to determine the neurochemical characteristics of Kiss1r-expressing neurones in the ARN using ISH and immunofluorescence. We revealed that the majority (approximately 63%) of Kiss1r-expressing neurones in the ARN were pro-opiomelanocortin (POMC) neurones, which have an anorexic effect in mammals. Additionally, a few Kiss1r-expressing neurones in the dorsal ARN are tuberoinfundibular dopamine (TIDA) neurones, which control milk production by inhibiting prolactin secretion from the anterior pituitary. TIDA neurones showed a relatively weak Kiss1r ISH signal compared to POMC neurones, as well as low co-expression of Kiss1r (approximately 15%). We also examined the expression of Kiss1r in neuropeptide Y and kisspeptin neurones, which are reported to arise from POMC-expressing progenitor cells during development. However, the vast majority of neuropeptide Y and kisspeptin neurones in the ARN did not express Kiss1r. These results suggest that kisspeptin may directly regulate energy homeostasis and milk production by modulating the activity of POMC and TIDA neurones, respectively. Our results provide an insight into the wide variety of roles that kisspeptin plays in homeostatic and neuroendocrine functions.

DOI： 10.1111/jne.12452

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ELSEVIER IRELAND LTD  

The inhalation anesthetic sevoflurane suppresses Per2 expression in the suprachiasmatic nucleus (SCN) in rodents. Here, we investigated the intra-SCN regional specificity, time-dependency, and pharmacological basis of sevoflurane-effects. Bioluminescence image was taken from the SCN explants of mPer2 promoter-destabilized luciferase transgenic rats, and each small regions of interest (ROI) of the image was analyzed. Sevoflurane suppressed bioluminescence in all ROIs, suggesting that all regions in the SCN are sensitive to sevoflurane. Clear time-dependency in sevoflurane effects were also observed; application during the trough phase of the bioluminescence cycle suppressed the subsequent increase in bioluminescence and resulted in a phase delay of the cycle; sevoflurane applied during the middle of the ascending phase induced a phase advance; sevoflurane on the descending phase showed no effect. These results indicate that the sevoflurane effect may depend on the intrinsic state of circadian machinery. Finally, we examined the involvement of GABAergic signal transduction in the sevoflurane effect. Co-application of both GABA(A) and GABA(B) receptor antagonists completely blocked the effect of sevoflurane on the bioluminescence rhythm, suggesting that sevoflurane inhibits Per2 expression via GABAergic signal transduction. Current study elucidated the anesthetic effects on the molecular mechanisms of circadian rhythm. (C) 2015 Elsevier Ireland Ltd and Japan Neuroscience Society. All rights reserved.

DOI： 10.1016/j.neures.2015.11.010

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ELSEVIER IRELAND LTD  

General anesthesia affects the expression of clock genes in various organs. Expression of Per2, a core component of the circadian clock, is markedly and reversibly suppressed by sevoflurane in the suprachiasmatic nucleus (SCN), and is considered to be a biochemical marker of anesthetic effect in the brain. The SCN contains various types of neurons, and this complexity makes it difficult to investigate the molecular mechanisms of anesthesia. Here, we established an in vitro experimental system using a cell line to investigate the mechanisms underlying anesthetic action. Development of the system comprised two steps: first, we developed a system for application of inhalational anesthetics and incubation; next, we established cultures of anesthetic-responsive cells expressing mPer2 promoter-dLuc. GT1-7 cells, derived from the mouse hypothalamus, responded to sevoflurane by reversibly decreasing mPer2-promoter-driven bioluminescence. Interestingly, the suppression of bioluminescence was found only in the serum-starved GT1-7 cells, which showed neuron-like morphology, but not in growing cells, suggesting that neuron-like characteristics are required for anesthetic effects in GT1-7 cells. (C) 2016 Elsevier Ireland Ltd. All rights reserved.

DOI： 10.1016/j.neulet.2016.04.005

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：WILEY-BLACKWELL  

The neuropeptide kisspeptin and its receptor play an essential role in reproduction as a potent modulator of the gonadotrophin-releasing hormone (GnRH) neurone. In addition to its reproductive function, kisspeptin signalling is also involved in extra-hypothalamic-pituitary-gonadal (HPG) axis systems, including oxytocin and arginine vasopressin (AVP) secretion. By contrast to the accumulating information for kisspeptin neurones and kisspeptin fibres, the histological distribution and function of the kisspeptin receptor in the rat brain remain poorly characterised. Using insitu hybridisation combined with immunofluorescence, the present study aimed to determine the whole brain map of Kiss1r mRNA (encoding the kisspeptin receptor), and to examine whether oxytocin or AVP neurones express Kiss1r. Neurones with strong Kiss1r expression were observed in several rostral brain areas, including the olfactory bulb, medial septum, diagonal band of Broca and throughout the preoptic area, with the most concentrated population being around 0.5mm rostral to the bregma. Co-immunofluorescence staining revealed that, in these rostral brain areas, the vast majority of the Kiss1r-expressing neurones co-expressed GnRH. Moderate levels of Kiss1r mRNA were also noted in the rostral periventricular area, paraventricular nucleus (PVN), and throughout the arcuate nucleus. Relatively weak Kiss1r expression was observed in the supraoptic nucleus and supramammillary nuclei. Moderate to weak expression of Kiss1r was also observed in several regions in the midbrain, including the periaqueductal gray and dorsal raphe nucleus. We also examined whether oxytocin and AVP neurones in the PVN co-express Kiss1r. Immunofluorescence revealed the co-expression of Kiss1r in a subset of the oxytocin neurones but not in the AVP neurones in the PVN. The present study provides a fundamental anatomical basis for further examination of the kisspeptin signalling system in the extra-HPG axis, as well as in reproductive function.

DOI： 10.1111/jne.12356

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：BIOSCIENTIFICA LTD  

In mammals, lactation suppresses GnRH/LH secretion resulting in transient infertility. In rats, GnRH/LH secretion is rescued within 18-48 h after pup separation (PS) and rapidly re-suppressed by subsequent re-exposure of pups. To elucidate the mechanisms underlying these rapid modulations, changes in the expression of kisspeptin, a stimulator of GnRH secretion, in several lactating conditions (normal-lactating; 4-h PS; 18-h PS; 4-h PS C1-h re-exposure of pups; non-lactating) were examined using in situ hybridization. PS for 4 h or 18 h increased Kiss1 expressing neurons in both the anteroventral periventricular nucleus (AVPV) and the arcuate nucleus (ARC), and subsequent exposure of pups re-suppressed Kiss1 in the AVPV. A change in Kiss1 expression was observed prior to the reported time of the change in GnRH/LH, indicating that the change in GnRH/LH results from changes in kisspeptin. We further examined the mechanisms underlying the rapid modulation of Kiss1. We first investigated the possible involvement of ascending sensory input during the suckling stimulus. Injection of the anterograde tracer to the subparafascicular parvocellular nucleus (SPFpc) in the midbrain, which relays the suckling stimulus, revealed direct neuronal connections between the SPFpc and kisspeptin neurons in both the AVPV and ARC. We also examined the possible involvement of prolactin (PRL). Administration of PRL for 1 h suppressed Kiss1 expression in the AVPV but not in the ARC. These results indicate that suckling stimulus rapidly modulates Kiss1 expression directly via neuronal connections and indirectly through serum PRL, resulting in modulation in GnRH/LH secretion.

DOI： 10.1530/JOE-15-0143

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：SPRINGER JAPAN KK  

We investigated age-induced changes in mRNA expression profiles of sex-steroidogenic enzymes and sex-steroid receptors in 3-, 12-, and 24-month-old male rat brain subregions [cerebral cortex (CC), hypothalamus (Hy) and cerebellum (CL)]. In many cases, the expression levels of mRNA decreased with age for androgen synthesis enzyme systems, including Cyp17a1, Hsd17b and Srd5a in the CC and CL, but not in the Hy. Estradiol synthase Cyp19a1 did not show age-induced decline in the Hy, and nearly no expression of Cyp19a1 was observed in the CC and CL over 3-24 m. Androgen receptor Ar increased in the Hy but decreased in the CC with age. Estrogen receptor Esr1 increased in the CC and Hy, and did not change in the CL with age. Esr2 did not change in the CC and Hy, but decreased in the CL with age. As a comparison, age-induced changes of brain-derived neurotrophic factor mRNA were also investigated.

DOI： 10.1007/s12576-015-0363-x

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：PUBLIC LIBRARY SCIENCE  

Background: We previously reported that sevoflurane anesthesia reversibly suppresses the expression of the clock gene, Period2 (Per2), in the mouse suprachiasmatic nucleus (SCN). However, the molecular mechanisms underlying this suppression remain unclear. In this study, we examined the possibility that sevoflurane suppresses Per2 expression via epigenetic modification of the Per2 promoter.
Methods: Mice were anesthetized with a gas mixture of 2.5% sevoflurane/40% oxygen at a 6 L/min flow for 1 or 4 h. After termination, brains were removed and samples of SCN tissue were derived from frozen brain sections. Chromatin immunoprecipitation (ChIP) assays using anti-acetylated-histone antibodies were performed to investigate the effects of sevoflurane on histone acetylation of the Per2 promoter. Interaction between the E'-box (a cis-element in the Per2 promoter) and CLOCK (the Clock gene product) was also assessed by a ChIP assay using an anti-CLOCK antibody. The SCN concentration of nicotinamide adenine dinucleotide (NAD(+)), a CLOCK regulator, was assessed by liquid chromatographymass spectrometry.
Results: Acetylation of histone H4 in the proximal region of the Per2 promoter was significantly reduced by sevoflurane. This change in the epigenetic profile of the Per2 gene was observed prior to suppression of Per2 expression. Simultaneously, a reduction in the CLOCK-E'-box interaction in the Per2 promoter was observed. Sevoflurane treatment did not affect the concentration of NAD(+) in the SCN.
Conclusions: Independent of NAD(+) concentration in the SCN, sevoflurane decreases CLOCK binding to the Per2 promoter E'-box motif, reducing histone acetylation and leading to suppression of Per2 expression.

DOI： 10.1371/journal.pone.0087319

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：FRONTIERS RESEARCH FOUNDATION  

Synaptic plasticity of the female hippocampus may cyclically fluctuate across the estrous cycle. The spine density fluctuation had been explained by fluctuation of plasma estradiol (E2) and progesterone (PROG), with the assumption that these steroids penetrate into the hippocampus. Recently, however, we demonstrated that male hippocampal levels of sex steroids are much higher than those in plasma, suggesting a weak contribution of plasma steroids to the spine density. By combination of mass-spectrometric analysis with HPLC purification and picolinoyl-derivatization of hippocampal sex steroids, we determined the accurate concentration of E2 and PROG at four stages of plasma estrous cycle including Proestrus (Pro), Estrus (Est), Diestrus 1 (D1), and Diestrus 2 (D2). Hippocampal levels of E2 and PROG showed cyclic fluctuation with a peak at Pro for E2 and at D1 for PROG, having a positive correlation with the plasma estrous cycle. All these sex steroid levels are much higher in the hippocampus than in plasma. Even after ovariectomy a significant levels of E2 and PROG were observed in the hippocampus. The total spine density showed higher values at Pro and D1, and lower values at Est and D2, having a good correlation with the peak levels of hippocampal E2 or PROG. We also examined fluctuation of the head diameter of spines. Interestingly, mRNA expression level of steroidogenic enzymes (P450arom and 17 beta-HSD, etc.) and sex-steroid receptors did not significantly change across the estrous cycle. Therefore, the fluctuation of total hippocampal PROG(equal to sum of hippocampus-synthesized PROG and plasma PROG) may be originated from the contribution of cyclic change in plasma PROG, which can induce the fluctuation of total hippocampal E2, since steroid conversion activity of hippocampus might be nearly the same across the estrus cycle.

DOI： 10.3389/fncir.2013.00149

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Background: Our previous studies revealed that application of the inhalation anesthetic, sevoflurane, reversibly repressed the expression of Per2 in the mouse suprachiasmatic nucleus (SCN). We aimed to examine whether sevoflurane directly affects the SCN. Methods: We performed in vivo and in vitro experiments to investigate rat Per2 expression under sevoflurane-treatment. The in vivo effects of sevoflurane on rPer2 expression were examined by quantitative in situ hybridization with a radioactively-labeled cRNA probe. Additionally, we examined the effect of sevoflurane anesthesia on rest/activity rhythms in the rat. In the in vitro experiments, we applied sevoflurane to SCN explant cultures from Per2-dLuc transgenic rats, and monitored luciferase bioluminescence, representing Per2 promoter activity. Bioluminescence from two peripheral organs, the kidney cortex and the anterior pituitary gland, were also analyzed. Results: Application of sevoflurane in rats significantly suppressed Per2 expression in the SCN compared with untreated animals. We observed no sevoflurane-induced phase-shift in the rest/activity rhythms. In the in vitro experiments, the intermittent application of sevoflurane repressed the increase of Per2-dLuc luminescence and led to a phase delay in the Per2-dLuc luminescence rhythm. Sevoflurane treatment did not suppress bioluminescence in the kidney cortex or the anterior pituitary gland. Conclusion: The suppression of Per2-dLuc luminescence by sevoflurane in in vitro SCN cultures isolated from peripheral inputs and other nuclei suggest a direct action of sevoflurane on the SCN itself. That sevoflurane has no such effect on peripheral organs suggests that this action might be mediated through a neuron-specific cellular mechanism or a regulation of the signal transduction between neurons. © 2013 Anzai et al.

DOI： 10.1371/journal.pone.0059454

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：SPRINGER JAPAN KK  

Kisspeptins, encoded by Kiss1 gene, play pivotal roles in the regulation of reproduction. Recently, several studies reported a sex difference in Kiss1 expression in the arcuate nucleus (ARC) during the neonatal period. In this study, we investigated the effect of gonadal steroid manipulation on the sex difference in Kiss1 expression in ARC of rats. At neonatal and prepubertal stages, females had a greater number of Kiss1 neurons than the males. Gonadectomy at those stages resulted in significant increases in the Kiss1 neuron number and the sex differences disappeared. We also confirmed the expression of estrogen receptor alpha in kisspeptin neurons in neonates. Altogether, our results indicate that ARC Kiss1 expression is negatively regulated by gonadal steroids from early postnatal stages, and that the sex difference in ARC Kiss1 expression is attributed to the difference in circulating gonadal steroid levels. We also found that neonatal estrogenization inhibits Kiss1 expression and impairs negative feedback system.

DOI： 10.1007/s12576-012-0222-y

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ELSEVIER IRELAND LTD  

Kisspeptin, a neuropeptide encoded by Kiss1 gene, plays pivotal roles in the regulation of reproductive function. Recently various stressors and stress-induced molecules such as corticotropin-releasing hormone (CRH) and corticosterone have been shown to inhibit Kiss? expression in rat hypothalamus. To determine whether CRH and glucocorticoids directly act on kisspeptin neurons, we examined the colocalization of CRH receptor (CRH-R) and glucocorticoid receptor (GR) in kisspeptin neurons in the female rat hypothalamus. Double-labeling immunohistochemistry revealed that most kisspeptin neurons in the anteroventral periventricular nucleus and periventricular nucleus continuum (AVPV/PeN), and arcuate nucleus (ARC) expressed CRH-R. We also observed a few close appositions of CRH immunoreactive fibers on some of kisspeptin neurons in AVPV/PeN and ARC. On the other hand, most kisspeptin neurons in AVPV/PeN expressed GR, whereas only a few of kisspeptin neurons in ARC expressed GR.
Altogether, our study provides neuroanatomical evidence of the direct modulation of kisspeptin neurons by CRH and glucocorticoids and suggests that stress-induced CRH and glucocorticoids inhibit gonadotropin secretion via the kisspeptin system. (C) 2012 Elsevier Ireland Ltd. All rights reserved.

DOI： 10.1016/j.neulet.2012.10.010

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ELSEVIER IRELAND LTD  

Some anesthetics can affect gene expression. Previously, we reported that sevoflurane anesthesia drastically and reversibly repressed the expression of mouse Per2 (mPer2), a core clock gene in the suprachiasmatic nucleus (SCN). In the current study, we examined the time-dependent effect of sevoflurane on mPer2 expression and its interactions with the circadian rest/activity rhythm of mice. During certain hours of the day, mice were anesthetized with 2.5% sevoflurane in 40% oxygen for 4 h. The expression level of mPer2 in the SCN was measured by in situ hybridization using a radiolabeled cRNA probe. Anesthesia during the morning hours showed the greatest repressive effect on mPer2 expression. Sevoflurane anesthesia repressed mPer2 expression during the conditions of light/dark and constant dark, and the light conditions modified the repression rate under anesthesia. Moreover, anesthesia in the morning also repressed mPer2 expression the following day. This dominant effect of anesthesia in the morning indicates that sevoflurane anesthesia affects the onset of mPer2 transcription. Behavior analysis revealed that the anesthetic treatment also induced a phase-delay in the rest/activity rhythm. However, no time-dependent effects of anesthesia on the circadian rest/activity rhythm were observed. Further investigation into the molecular events caused by anesthesia are required to explain atypical clinical signs observed in patients after surgical procedures, such as fatigue, sleep disorder, mood alteration and delirium. (c) 2012 Elsevier Ireland Ltd. All rights reserved.

DOI： 10.1016/j.neulet.2012.07.061

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記述言語：英語   出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD  

The hippocampus synthesizes estrogen and androgen in addition to the circulating sex steroids. Synaptic modulation by hippocampus-derived estrogen or androgen is essential to maintain healthy memory processes. Rapid actions (1-2 h) of 17 beta-estradiol (17 beta-E2) occur via synapse-localized receptors (ER alpha or ER beta), while slow genomic E2 actions (6-48 h) occur via classical nuclear receptors (ER alpha or ER beta). The long-term potentiation (LTP), induced by strong tetanus or theta-burst stimulation, is not further enhanced by E2 perfusion in adult rats. Interestingly, E2 perfusion can rescue corticosterone (stress hormone)-induced suppression of LIP. The long-term depression is modulated rapidly by E2 perfusion. Elevation of the E2 concentration changes rapidly the density and head structure of spines in neurons. ER alpha, but not ER beta, drives this enhancement of spinogenesis. Kinase networks are involved downstream of ER alpha. Testosterone (T) or dihydrotestosterone (DHT) also rapidly modulates spinogenesis. Newly developed Spiso-3D mathematical analysis is used to distinguish these complex effects by sex steroids and kinases.
It has been doubted that the level of hippocampus-derived estrogen and androgen may not be high enough to modulate synaptic plasticity. Determination of the accurate concentration of E2, T or DHT in the hippocampus is enabled by mass-spectrometric analysis in combination with new steroid-derivatization methods. The E2 level in the hippocampus is approximately 8 nM for the male and 0.5-2 nM for the female, which is much higher than that in circulation. The level of T and DHT is also higher than that in circulation. Taken together, hippocampus-derived E2, T, and DHT play a major role in modulation of synaptic plasticity. (C) 2011 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.jsbmb.2011.10.004

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：PUBLIC LIBRARY SCIENCE  

Background: Brain synthesis of steroids including sex-steroids is attracting much attention. The endogenous synthesis of corticosteroids in the hippocampus, however, has been doubted because of the inability to detect deoxycorticosterone (DOC) synthase, cytochrome P450(c21).
Methodology/Principal Findings: The expression of P450(c21) was demonstrated using mRNA analysis and immmunogold electron microscopic analysis in the adult male rat hippocampus. DOC production from progesterone (PROG) was demonstrated by metabolism analysis of (3)H-steroids. All the enzymes required for corticosteroid synthesis including P450(c21), P450(2D4), P450(11 beta 1) and 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) were localized in the hippocampal principal neurons as shown via in situ hybridization and immunoelectron microscopic analysis. Accurate corticosteroid concentrations in rat hippocampus were determined by liquid chromatography-tandem mass spectrometry. In adrenalectomized rats, net hippocampus-synthesized corticosterone (CORT) and DOC were determined to 6.9 and 5.8 nM, respectively. Enhanced spinogenesis was observed in the hippocampus following application of low nanomolar (10 nM) doses of CORT for 1 h.
Conclusions/Significance: These results imply the complete pathway of corticosteroid synthesis of 'pregnenolone -> PROG -> DOC -> CORT' in the hippocampal neurons. Both P450(c21) and P450(2D4) can catalyze conversion of PROG to DOC. The low nanomolar level of CORT synthesized in hippocampal neurons may play a role in modulation of synaptic plasticity, in contrast to the stress effects by micromolar CORT from adrenal glands.

DOI： 10.1371/journal.pone.0021631

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Estradiol is synthesized from cholesterol in hippocampal neurons of adult rats by cytochrome P450 and hydroxyste-roid dehydrogenase enzymes. These enzymes are expressed in the glutamatergic neurons of the hippocampus. Surprisingly., the concentration of estradiol and androgen in the hippocampus is significantly higher than that in circulation. Locally synthesized estradiol rapidly and potently modulates synaptic plasticity within the hippocampus. E2 rapidly potentiates long-term depression and induces spinogenesis through synaptic estrogen receptors and kinases. The rapid effects of estradiol are followed by slow genomic effects mediated by both estrogen receptors located at the synapse and nucleus., modulating long-term potentiation and promoting the formation of new functional synaptic contacts. Age-related changes in hippocampally derived estradiol synthesis and distribution of estrogen receptors may alter synaptic plasticity., and could potentially contribute to age-related cognitive decline. Understanding factors which regulate hippocampal estradiol synthesis could lead to the identification of alternatives to conventional hormone therapy to protect against age-related cognitive decline. © 2011, by Walter de Gruyter Berlin Boston. All rights reserved.

DOI： 10.1515/HMBCI.2011.118

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Sex steroids play essential roles in the modulation of synaptic plasticity and neuroprotection in the hippocampus. Accumulating evidence shows that hippocampal neurons synthesize both estrogen and androgen. Recently, we also revealed the hippocampal synthesis of corticosteroids. The accurate concentrations of these hippocampus-synthesized steroids are determined by liquid chromatography-tandem mass-spectrometry in combination with novel derivatization. The hippocampal levels of 17β-estradiol (E2), testosterone (T), dihydrotestosterone (DHT), and corticosterone (CORT), are 5-15 nM, and these levels are sufficient to modulate synaptic plasticity. Hippocampal E2 modulates memory-related synaptic plasticity not only slowly/genomically but also rapidly/non-genomically. Slow actions of E2 occur via classical nuclear receptors (ERα or ERβ), while rapid E2 actions occur via synapse-localized or extranuclear ERα or ERβ. Nanomolar concentrations of E2 change rapidly the density and morphology of spines in hippocampal neurons. ERα, but not ERβ, drives this enhancement/suppression of spinogenesis in adult animals. Nanomolar concentrations of androgens (T and DHT) and CORT also increase the spine density. Kinase networks are involved downstream of ERα and androgen receptor. Newly developed Spiso-3D mathematical analysis is useful to distinguish these complex effects by sex steroids and kinases. Significant advance has been achieved in investigations of rapid modulation by E2 of the long-term depression or the long-term potentiation.

DOI： 10.3389/fendo.2011.00043

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ENDOCRINE SOC  

Although sex steroids play a crucial role in the postnatal brain development, the age-related changes in the hippocampal steroidogenesis remain largely unknown. We performed comprehensive investigations for the mRNA expressions of 26 sex steroidogenic enzymes/proteins and three sex steroid receptors in the male rat hippocampus, at the ages of postnatal day (PD) 1, PD4, PD7, PD10, PD14, 4 wk, and 12 wk (adult), by RT-PCR/Southern blotting analysis. The relative expression levels of these enzymes/receptors at PD1 were Srd5a1 > Star > Ar similar to Hsd17b4 similar to Hsd17b1 similar to Hsd17b7 similar to Esr1 similar to Srd5a2 > Hsd17b3 > Esr2 > Cyp11a1 > Cyp17a1 > Cyp19a1 similar to Hsd17b2 > 3 beta-hydroxysteroid dehydrogenase I. The mRNA levels of essential enzymes for progesterone/testosterone/estradiol metabolisms (Cyp17a1, Hsd17b7, and Cyp19a1) were approximately constant between PD1 and PD14 and then declined toward the adult levels. Cyp11a1 increased during PD4-PD14 and then considerably decreased toward the adult level (similar to 8% of PD1). Hsd17b1, Hsd17b2, and 3 beta-hydroxysteroid dehydrogenase I mRNA decreased approximately monotonously. Hsd17b3 increased to approximately 200% of PD1 during PD4-PD14 and was maintained at this high level. The 5 alpha-reductase mRNA was maintained constant (Srd5a1) or decreased monotonically (Srd5a2) toward the adult level. The Esr1 level peaked at PD4 and decreased toward the adult level, whereas Ar greatly increased during PD1-PD14 and was maintained at this high level. The Star and Hsd17b4 levels were maintained constant from neonate to adult. These results suggest that the hippocampal sex steroidogenic properties are substantially altered during the postnatal development processes, which might contribute to brain sexual maturation. (Endocrinology 151: 5795-5806, 2010)

DOI： 10.1210/en.2010-0581

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ELSEVIER SCIENCE BV  

The hippocampus is a center for learning and memory as well as a target of Alzheimer's disease in aged humans. Synaptic modulation by estrogen is essential to understand the molecular mechanisms of estrogen replacement therapy. Because the local synthesis of estrogen occurs in the hippocampus of both sexes, in addition to the estrogen supply from the gonads, its functions are attracting much attention.
Hippocampal estrogen modulates memory-related synaptic plasticity not only slowly but also rapidly. Slow actions of 17 beta-estradiol (17 beta-E2) occur via classical nuclear receptors (ER alpha or ER beta), while rapid E2 actions occur via synapse-localized ER alpha or ER beta. Elevation or decrease of the E2 concentration changes rapidly the density and morphology of spines in CA1-CA3 neurons. ER alpha, but not ER beta, drives this enhancement/suppression of spinogenesis. Kinase networks are involved downstream of ER alpha. The long-term depression but not the long-term potentiation is modulated rapidly by changes of E2 level.
Determination of the E2 concentration in the hippocampus is enabled by mass-spectrometry in combination with derivatization methods. The E2 level in the hippocampus is as high as approx. 8 nM for the male and 0.5-2 nM for the female, which is much higher than that in circulation. Therefore, hippocampus-derived E2 plays a major role in modulation of synaptic plasticity.
Many hippocampal slice experiments measure the restorative effects of E2 by supplementation of E2 to E2-depleted slices. Accordingly, isolated slice experiments can be used as in vitro models of in vivo estrogen replacement therapy for ovariectomized female animals with depleted circulating estrogen. (C) 2009 Elsevier By. All rights reserved.

DOI： 10.1016/j.bbagen.2009.11.002

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ENDOCRINE SOC  

Estradiol (E2) and other sex steroids play essential roles in the modulation of synaptic plasticity and neuroprotection in the hippocampus. To clarify the mechanisms for these events, it is important to determine the respective role of circulating vs. locally produced sex steroids in the male hippocampus. Liquid chromatography-tandem mass spectrometry in combination with novel derivatization was employed to determine the concentration of sex steroids in adult male rat hippocampus. The hippocampal levels of 17 beta-E2, testosterone (T), and dihydrotestosterone (DHT) were 8.4, 16.9, and 6.6 nM, respectively, and these levels were significantly higher than circulating levels. The hippocampal estrone (E1) level was, in contrast, very low around 0.015 nM. After castration to deplete circulating high level T, hippocampal levels of T and DHT decreased considerably to 18 and 3%, respectively, whereas E2 level only slightly decreased to 83%. The strong reduction in hippocampal DHT resulting from castration implies that circulating T may be a main origin of DHT. In combination with results obtained from metabolism analysis of [(3)H]steroids, we suggest that male hippocampal E2 synthesis pathway may be androstenedione -> T -> E2 or dehydroepiandrosterone -> androstenediol -> T -> E2 but not androstenedione -> E1 -> E2. (Endocrinology 150: 5106-5112, 2009)

DOI： 10.1210/en.2009-0305

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ACADEMIC PRESS INC ELSEVIER SCIENCE  

Sex-steroid synthesis in the hippocampus had been thought to be much more active at the neonatal stage than at the adult stage. However, the detailed comparison between these two stages had not been demonstrated yet. Here we performed the comparison about the mRNA level of steroidogenic enzymes and the rate of steroid metabolism between these two stages of the hippocampus. The relative expression level of P450(17 alpha), 17 beta- or 3 beta-hydroxysteroid dehydrogenase, or P450arom was approximately 1.3-1.5-fold higher at the neonatal than at the adult stage. The rate of sex-steroid metabolism (from dehydroepiandrosterone to estradiol) was 2-7-fold (depending on different steps) more rapid at the neonatal than at the adult stage. Taken together, neonatal steroidogenesis is moderately more active than adult steroidogenesis. (C) 2009 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.bbrc.2009.05.005

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ELSEVIER IRELAND LTD  

Estrogen and androgen are synthesized from cholesterol locally in hippocampal neurons of adult animals. These neurosteroids are synthesized by cytochrome P450s and hydroxysteroid dehydrogenases (HSDs) and 5alpha-reductase. The expression levels of enzymes are as low as 1/200-1/50,000 of those in endocrine organs, however these numbers are high enough for local synthesis. Localization of P450(17alpha), P450arom, 17beta-HSD and 5alpha-reductase is observed in principal glutamatergic neurons in CA1, CA3 and the dendate gyrus. Several nanomolar levels of estrogen and androgen are observed in the hippocampus.
Estrogen modulates memory-related synaptic plasticity not only slowly but also rapidly in the hippocampus. Rapid action of 17beta-estradiol via membrane receptors is demonstrated for spinogenesis and long-term depression (LTD). The enhancement of LTD by 1-10nM estradiol occurs within I h. The density of spine is increased in CA1 pyramidal neurons within 2 h after application of estradiol. The density of spine-like structure is, however, decreased by estradiol in CA3 pyramidal neurons. ERalpha, but not ERbeta, induces the same enhancement/suppression effects on both spinogenesis and LTD. (C) 2008 Elsevier Ireland Ltd. All rights reserved.

DOI： 10.1016/j.mce.2008.04.017

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記述言語：日本語   出版者・発行元：日本組織細胞化学会  

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記述言語：日本語  

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記述言語：日本語   出版者・発行元：(一社)日本内分泌学会  

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記述言語：日本語  

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記述言語：日本語   出版者・発行元：日本組織細胞化学会  

CiNii Books

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その他リンク： http://search.jamas.or.jp/link/ui/2016046992

記述言語：日本語   出版者・発行元：日本組織細胞化学会  

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記述言語：日本語  

J-GLOBAL

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記述言語：日本語   出版者・発行元：(一社)日本内分泌学会  

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記述言語：日本語  

J-GLOBAL

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記述言語：英語   掲載種別：研究発表ペーパー・要旨（国際会議）   出版者・発行元：ELSEVIER IRELAND LTD  

DOI： 10.1016/j.neures.2011.07.1159

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記述言語：英語   掲載種別：研究発表ペーパー・要旨（国際会議）   出版者・発行元：ELSEVIER IRELAND LTD  

DOI： 10.1016/j.neures.2011.07.1152

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記述言語：英語   掲載種別：研究発表ペーパー・要旨（国際会議）   出版者・発行元：ELSEVIER IRELAND LTD  

DOI： 10.1016/j.neures.2010.07.1250

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記述言語：英語   掲載種別：研究発表ペーパー・要旨（国際会議）   出版者・発行元：ELSEVIER IRELAND LTD  

DOI： 10.1016/j.neures.2010.07.1249

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記述言語：英語   掲載種別：研究発表ペーパー・要旨（国際会議）   出版者・発行元：SPRINGER TOKYO  

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記述言語：英語   掲載種別：研究発表ペーパー・要旨（国際会議）   出版者・発行元：ELSEVIER IRELAND LTD  

DOI： 10.1016/j.neures.2009.09.1238

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記述言語：英語   掲載種別：研究発表ペーパー・要旨（国際会議）   出版者・発行元：ELSEVIER IRELAND LTD  

DOI： 10.1016/j.neures.2009.09.1233

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記述言語：英語   掲載種別：研究発表ペーパー・要旨（国際会議）   出版者・発行元：ELSEVIER IRELAND LTD  

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記述言語：英語   掲載種別：研究発表ペーパー・要旨（国際会議）   出版者・発行元：ELSEVIER IRELAND LTD  

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記述言語：英語   出版者・発行元：(一社)日本生物物理学会  

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記述言語：英語   掲載種別：研究発表ペーパー・要旨（国際会議）   出版者・発行元：ELSEVIER IRELAND LTD  

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記述言語：英語   掲載種別：研究発表ペーパー・要旨（国際会議）   出版者・発行元：ELSEVIER IRELAND LTD  

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記述言語：英語   掲載種別：研究発表ペーパー・要旨（国際会議）   出版者・発行元：ELSEVIER IRELAND LTD  

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記述言語：日本語   会議種別：口頭発表（一般）  

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記述言語：日本語   会議種別：シンポジウム・ワークショップ パネル（指名）  

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