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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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Takayama K, Tobori S, Andoh C, Kakae M, Hagiwara M, Nagayasu K, Shirakawa H, Ago Y, Kaneko S. Autism Spectrum Disorder Model Mice Induced by Prenatal Exposure to Valproic Acid Exhibit Enhanced Empathy-Like Behavior <i>via</i> Oxytocinergic Signaling. Biol Pharm Bull 2022; 45:1124-1132. [DOI: 10.1248/bpb.b22-00200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Kaito Takayama
- Department of Molecular Pharmacology, Graduate School of Pharmaceutical Sciences, Kyoto University
| | - Shota Tobori
- Department of Molecular Pharmacology, Graduate School of Pharmaceutical Sciences, Kyoto University
| | - Chihiro Andoh
- Department of Molecular Pharmacology, Graduate School of Pharmaceutical Sciences, Kyoto University
| | - Masashi Kakae
- Department of Molecular Pharmacology, Graduate School of Pharmaceutical Sciences, Kyoto University
| | - Masako Hagiwara
- Department of Molecular Pharmacology, Graduate School of Pharmaceutical Sciences, Kyoto University
| | - Kazuki Nagayasu
- Department of Molecular Pharmacology, Graduate School of Pharmaceutical Sciences, Kyoto University
| | - Hisashi Shirakawa
- Department of Molecular Pharmacology, Graduate School of Pharmaceutical Sciences, Kyoto University
| | - Yukio Ago
- Department of Cellular and Molecular Pharmacology, Graduate School of Biomedical and Health Sciences, Hiroshima University
| | - Shuji Kaneko
- Department of Molecular Pharmacology, Graduate School of Pharmaceutical Sciences, Kyoto University
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Higashida H, Furuhara K, Lopatina O, Gerasimenko M, Hori O, Hattori T, Hayashi Y, Cherepanov SM, Shabalova AA, Salmina AB, Minami K, Yuhi T, Tsuji C, Fu P, Liu Z, Luo S, Zhang A, Yokoyama S, Shuto S, Watanabe M, Fujiwara K, Munesue SI, Harashima A, Yamamoto Y. Oxytocin Dynamics in the Body and Brain Regulated by the Receptor for Advanced Glycation End-Products, CD38, CD157, and Nicotinamide Riboside. Front Neurosci 2022; 16:858070. [PMID: 35873827 PMCID: PMC9301327 DOI: 10.3389/fnins.2022.858070] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 05/31/2022] [Indexed: 12/21/2022] Open
Abstract
Investigating the neurocircuit and synaptic sites of action of oxytocin (OT) in the brain is critical to the role of OT in social memory and behavior. To the same degree, it is important to understand how OT is transported to the brain from the peripheral circulation. To date, of these, many studies provide evidence that CD38, CD157, and receptor for advanced glycation end-products (RAGE) act as regulators of OT concentrations in the brain and blood. It has been shown that RAGE facilitates the uptake of OT in mother’s milk from the digestive tract to the cell surface of intestinal epithelial cells to the body fluid and subsequently into circulation in male mice. RAGE has been shown to recruit circulatory OT into the brain from blood at the endothelial cell surface of neurovascular units. Therefore, it can be said that extracellular OT concentrations in the brain (hypothalamus) could be determined by the transport of OT by RAGE from the circulation and release of OT from oxytocinergic neurons by CD38 and CD157 in mice. In addition, it has recently been found that gavage application of a precursor of nicotinamide adenine dinucleotide, nicotinamide riboside, for 12 days can increase brain OT in mice. Here, we review the evaluation of the new concept that RAGE is involved in the regulation of OT dynamics at the interface between the brain, blood, and intestine in the living body, mainly by summarizing our recent results due to the limited number of publications on related topics. And we also review other possible routes of OT recruitment to the brain.
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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, Japan
- Laboratory of Social Brain Study, Research Institute of Molecular Medicine and Pathobiochemistry, Krasnoyarsk State Medical University named after Professor V.F. Voino-Yasenetsky, Krasnoyarsk, Russia
- *Correspondence: Haruhiro Higashida,
| | - Kazumi Furuhara
- Department of Basic Research on Social Recognition and Memory, Research Center for Child Mental Development, Kanazawa University, Kanazawa, Japan
| | - Olga Lopatina
- Department of Basic Research on Social Recognition and Memory, Research Center for Child Mental Development, Kanazawa University, Kanazawa, Japan
- Laboratory of Social Brain Study, Research Institute of Molecular Medicine and Pathobiochemistry, Krasnoyarsk State Medical University named after Professor V.F. Voino-Yasenetsky, Krasnoyarsk, Russia
| | - Maria Gerasimenko
- Department of Basic Research on Social Recognition and Memory, Research Center for Child Mental Development, Kanazawa University, Kanazawa, Japan
| | - Osamu Hori
- Department of Neuroanatomy, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan
| | - Tsuyoshi Hattori
- Department of Neuroanatomy, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan
| | - Yasuhiko Hayashi
- Department of Neurosurgery, Kanazawa Medical University, Kanazawa, Japan
| | - Stanislav M. Cherepanov
- Department of Basic Research on Social Recognition and Memory, Research Center for Child Mental Development, Kanazawa University, Kanazawa, Japan
| | - Anna A. Shabalova
- Department of Basic Research on Social Recognition and Memory, Research Center for Child Mental Development, Kanazawa University, Kanazawa, Japan
| | - Alla B. Salmina
- Department of Basic Research on Social Recognition and Memory, Research Center for Child Mental Development, Kanazawa University, Kanazawa, Japan
- Laboratory of Social Brain Study, Research Institute of Molecular Medicine and Pathobiochemistry, Krasnoyarsk State Medical University named after Professor V.F. Voino-Yasenetsky, Krasnoyarsk, Russia
| | - Kana Minami
- Department of Basic Research on Social Recognition and Memory, Research Center for Child Mental Development, Kanazawa University, Kanazawa, Japan
| | - Teruko Yuhi
- Department of Basic Research on Social Recognition and Memory, Research Center for Child Mental Development, Kanazawa University, Kanazawa, Japan
| | - Chiharu Tsuji
- Department of Basic Research on Social Recognition and Memory, Research Center for Child Mental Development, Kanazawa University, Kanazawa, Japan
| | - PinYue Fu
- Department of Basic Research on Social Recognition and Memory, Research Center for Child Mental Development, Kanazawa University, Kanazawa, Japan
| | - Zhongyu Liu
- Department of Basic Research on Social Recognition and Memory, Research Center for Child Mental Development, Kanazawa University, Kanazawa, Japan
| | - Shuxin Luo
- Department of Basic Research on Social Recognition and Memory, Research Center for Child Mental Development, Kanazawa University, Kanazawa, Japan
| | - Anpei Zhang
- Department of Basic Research on Social Recognition and Memory, Research Center for Child Mental Development, Kanazawa University, Kanazawa, Japan
| | - Shigeru Yokoyama
- Department of Basic Research on Social Recognition and Memory, Research Center for Child Mental Development, Kanazawa University, Kanazawa, Japan
| | - Satoshi Shuto
- Faculty of Pharmaceutical Sciences, Center for Research and Education on Drug Discovery, Hokkaido University, Sapporo, Japan
| | - Mizuki Watanabe
- Faculty of Pharmaceutical Sciences, Center for Research and Education on Drug Discovery, Hokkaido University, Sapporo, Japan
| | - Koichi Fujiwara
- Faculty of Pharmaceutical Sciences, Center for Research and Education on Drug Discovery, Hokkaido University, Sapporo, Japan
| | - Sei-ichi Munesue
- Department of Biochemistry and Molecular Vascular Biology, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan
| | - Ai Harashima
- Department of Biochemistry and Molecular Vascular Biology, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan
| | - Yasuhiko Yamamoto
- Department of Biochemistry and Molecular Vascular Biology, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan
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Ueta Y. Transgenic approaches to opening up new fields of vasopressin and oxytocin research. J Neuroendocrinol 2021; 33:e13055. [PMID: 34713515 DOI: 10.1111/jne.13055] [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: 05/01/2021] [Revised: 10/07/2021] [Accepted: 10/07/2021] [Indexed: 11/29/2022]
Abstract
Transgenic approaches have been applied to generate transgenic rats that express exogenous genes in arginine vasopressin (AVP)- and oxytocin (OXT)-producing magnocellular neurosecretory cells (MNCs) of the hypothalamic-neurohypophyseal system (HNS). First, the fusion gene that expresses AVP-enhanced green fluorescent protein (eGFP) and OXT-monomeric red fluorescent protein 1 (mRFP1) was used to visualize AVP- and OXT-producing MNCs and their axon terminals in the HNS under fluorescence microscopy. Second, the fusion gene that expresses c-fos-eGFP and c-fos-mRFP1 was used to identify activated neurons physiologically in the central nervous system, including MNCs, circumventricular organs and spinal cord. In addition, AVP-eGFP x c-fos-mRFP1 and OXT-mRFP1 × c-fos-eGFP double transgenic rats were generated to identify activated AVP- and OXT-producing MNCs using appropriate physiological stimuli. Third, the fusion gene that expresses AVP-chanelrhodopsin 2 (ChR2)-eGFP and AVP-hM3Dq-mCherry was used to activate AVP- and OXT-producing MNCs by optogenetic and chemogenetic approaches. In each step, these transgenic approaches in rats have provided new insights on the physiological roles of AVP and OXT not only in the HNS, but also in the whole body. In this review, we summarize the transgenic rats that we generated, as well as related physiological findings.
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Affiliation(s)
- Yoichi Ueta
- Department of Physiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan
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Huang ST, Song ZJ, Liu Y, Luo WC, Yin Q, Zhang YM. BNST AV GABA-PVN CRF Circuit Regulates Visceral Hypersensitivity Induced by Maternal Separation in Vgat-Cre Mice. Front Pharmacol 2021; 12:615202. [PMID: 33815103 PMCID: PMC8017215 DOI: 10.3389/fphar.2021.615202] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 02/04/2021] [Indexed: 12/12/2022] Open
Abstract
Visceral hypersensitivity as a common clinical manifestation of irritable bowel syndrome (IBS) may contribute to the development of chronic visceral pain. Our prior studies authenticated that the activation of the corticotropin-releasing factor (CRF) neurons in paraventricular nucleus (PVN) contributed to visceral hypersensitivity in mice, but puzzles still remain with respect to the underlying hyperactivation of corticotropin-releasing factor neurons. Herein, we employed maternal separation (MS) to establish mouse model of visceral hypersensitivity. The neuronal circuits associated with nociceptive hypersensitivity involved paraventricular nucleus CRF neurons by means of techniques such as behavioral test, pharmacology, molecular biology, retrograde neuronal circuit tracers, electrophysiology, chemogenetics and optogenetics. MS could predispose the elevated firing frequency of CRF neurons in PVN in murine adulthood, which could be annulled via the injection of exogenous GABA (0.3mM, 0.2µl) into PVN. The PVN-projecting GABAergic neurons were mainly distributed in the anterior ventral (AV) region in the bed nucleus of stria terminalis (BNST), wherein the excitability of these GABAergic neurons was reduced. Casp3 virus was utilized to induce apoptosis of GABA neurons in BNST-AV region, resulting in the activation of CRF neurons in PVN and visceral hyperalgesia. In parallel, chemogenetic and optogenetic approaches to activate GABAergic BNSTAV-PVN circuit in MS mice abated the spontaneous firing frequency of PVN CRF neurons and prevented the development of visceral hypersensitivity. A priori, PVNCRF-projecting GABAergic neurons in BNST-AV region participated in the occurrence of visceral hypersensitivity induced by MS. Our research may provide a new insight into the neural circuit mechanism of chronic visceral pain.
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Affiliation(s)
- Si-Ting Huang
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, China
| | - Zhi-Jing Song
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, China.,Department of Anesthesiology, Xuzhou Municipal Hospital Affiliated with Xuzhou Medical University, Xuzhou, China
| | - Yu Liu
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, China
| | - Wen-Chen Luo
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, China
| | - Qian Yin
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, China
| | - Yong-Mei Zhang
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, China
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Munesue SI, Liang M, Harashima A, Zhong J, Furuhara K, Boitsova EB, Cherepanov SM, Gerasimenko M, Yuhi T, Yamamoto Y, Higashida H. Transport of oxytocin to the brain after peripheral administration by membrane-bound or soluble forms of receptors for advanced glycation end-products. J Neuroendocrinol 2021; 33:e12963. [PMID: 33733541 DOI: 10.1111/jne.12963] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 02/26/2021] [Accepted: 02/26/2021] [Indexed: 12/22/2022]
Abstract
Oxytocin (OT) is a neuropeptide hormone. Single and repetitive administration of OT increases social interaction and maternal behaviour in humans and mammals. Recently, it was found that the receptor for advanced glycation end-products (RAGE) is an OT-binding protein and plays a critical role in the uptake of OT to the brain after peripheral OT administration. Here, we address some unanswered questions on RAGE-dependent OT transport. First, we found that, after intranasal OT administration, the OT concentration increased in the extracellular space of the medial prefrontal cortex (mPFC) of wild-type male mice, as measured by push-pull microperfusion. No increase of OT in the mPFC was observed in RAGE knockout male mice. Second, in a reconstituted in vitro blood-brain barrier system, inclusion of the soluble form of RAGE (endogenous secretory RAGE [esRAGE]), an alternative splicing variant, in the luminal (blood) side had no effect on the transport of OT to the abluminal (brain) chamber. Third, OT concentrations in the cerebrospinal fluid after i.p. OT injection were slightly higher in male mice overexpressing esRAGE (esRAGE transgenic) compared to those in wild-type male mice, although this did not reach statistical significance. Although more extensive confirmation is necessary because of the small number of experiments in the present study, the reported data support the hypothesis that RAGE may be involved in the transport of OT to the mPFC from the circulation. These results suggest that the soluble form of RAGE in the plasma does not function as a decoy in vitro.
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Affiliation(s)
- Sei-Ichi Munesue
- Department of Biochemistry and Molecular Vascular Biology, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan
| | - MingKun Liang
- Department of Basic Research on Social Recognition and Memory, Research Centre for Child Mental Development, Kanazawa University, Kanazawa, Japan
| | - Ai Harashima
- Department of Biochemistry and Molecular Vascular Biology, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan
| | - Jing Zhong
- Department of Basic Research on Social Recognition and Memory, Research Centre for Child Mental Development, Kanazawa University, Kanazawa, Japan
| | - Kazumi Furuhara
- Department of Basic Research on Social Recognition and Memory, Research Centre for Child Mental Development, Kanazawa University, Kanazawa, Japan
| | - Elizabeta B Boitsova
- Department of Biochemistry and Molecular Vascular Biology, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan
- Laboratory for Social Brain Studies, Research Institute of Molecular Medicine and Pathobiochemistry, Department of Biochemistry, Krasnoyarsk State Medical University named after Prof. V. F. Voino-Yasentsky, Krasnoyarsk, Russia
| | - Stanislav M Cherepanov
- Department of Basic Research on Social Recognition and Memory, Research Centre for Child Mental Development, Kanazawa University, Kanazawa, Japan
| | - Maria Gerasimenko
- Department of Basic Research on Social Recognition and Memory, Research Centre for Child Mental Development, Kanazawa University, Kanazawa, Japan
| | - Teruko Yuhi
- Department of Basic Research on Social Recognition and Memory, Research Centre for Child Mental Development, Kanazawa University, Kanazawa, Japan
| | - Yasuhiko Yamamoto
- Department of Biochemistry and Molecular Vascular Biology, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan
| | - Haruhiro Higashida
- Department of Basic Research on Social Recognition and Memory, Research Centre for Child Mental Development, Kanazawa University, Kanazawa, Japan
- Laboratory for Social Brain Studies, Research Institute of Molecular Medicine and Pathobiochemistry, Department of Biochemistry, Krasnoyarsk State Medical University named after Prof. V. F. Voino-Yasentsky, Krasnoyarsk, Russia
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Dudás B, Merchenthaler I. Morphology and distribution of hypothalamic peptidergic systems. HANDBOOK OF CLINICAL NEUROLOGY 2021; 179:67-85. [PMID: 34225984 DOI: 10.1016/b978-0-12-819975-6.00002-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Neuropeptides participate in the regulation of numerous hypothalamic functions that are aimed for sustaining the homeostasis of the organism. These neuropeptides can act in two different levels. They can influence the release of hormones from the adenohypophysis via the portal circulation; in addition, they can act as neurotransmitters/neuromodulators modulating the functioning of numerous hypothalamic neurotransmitter systems. Indeed, most of these peptidergic systems form a complex network in the infundibular and periventricular nuclei of the human hypothalamus, communicating with each other by synaptic connections that may control fundamental physiologic functions. In the present chapter, we provide an overview of the distribution of neuropeptides in the human hypothalamus using immunohistochemistry and high-resolution, three-dimensional mapping.
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Affiliation(s)
- Bertalan Dudás
- Neuroendocrine Organization Laboratory, Lake Erie College of Osteopathic Medicine, Erie, PA, United States; Department of Anatomy, Histology and Embryology, University of Szeged, Szeged, Hungary.
| | - István Merchenthaler
- Department of Epidemiology and Public Health and of Anatomy and Neurobiology, University of Maryland Baltimore, Baltimore, MD, United States
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Dudas B, Merchenthaler I. Thyrotropin-releasing hormone axonal varicosities appear to innervate dopaminergic neurons in the human hypothalamus. Brain Struct Funct 2020; 225:2193-2201. [PMID: 32737582 DOI: 10.1007/s00429-020-02120-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 07/23/2020] [Indexed: 01/25/2023]
Abstract
Thyrotropin-releasing hormone (TRH) has a critical role in the central regulation of thyroid-stimulating hormone (TSH) from the anterior pituitary, and subsequently, thyroid hormone secretion from the thyroid gland. In addition to its role in the regulation of HPT axis, TRH is a potent regulator of prolactin (PRL) secretion by stimulating PRL secretion either directly from lactotrophs or indirectly via its action on the tuberoinfundibular dopamine (TIDA) neurons. In rodents, the TRH neurons which regulate TSH and thyroid hormone secretion, called hypophysiotropic TRH neurons, are in the medial subdivision of the parvicellular paraventricular nucleus (PVN). In humans, the PVN also contains a large population of TRH neurons, especially in its medial part, but the location of hypophysiotropic TRH neurons is not yet known. In addition to regulating TSH and PRL secretion, TRH also functions as a neurotransmitter/neuromodulator. In rodents and teleosts, TRH axons densely innervate TIDA neurons to inhibit tyrosine hydroxylase (TH) biosynthesis, neuronal firing, and dopamine turnover which may contribute to increasing PRL secretion. No such connections have been reported in humans, although dopaminergic neurons express TRH receptors and TRH also regulates PRL secretion. The objectives of this study were to map TRH-IR and TH-IR structures in the human hypothalamus with single-label light microscopic immunocytochemistry and study their interaction with double-label light microscopic immunocytochemistry. We show that TRH-IR nerve terminals densely surround TH-IR neurons (perikarya and dendrites) in the infundibulum of the human hypothalamus. The micrographs illustrating these juxtapositions were taken by Olympus BX45 microscope equipped with a digital camera and with 100X oil immersion objective. Composite images were created from the consecutive micrographs if the neurons were larger than the frame of the camera, using Adobe Photoshop software. As no gaps between TRH-IR and TH-IR elements were seen, these contacts may be functional synapses by which TRH regulates the activity of dopaminergic neurons and subsequently TSH and PRL secretion.
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Affiliation(s)
- Bertalan Dudas
- Neuroendocrine Organization Laboratory (NEO), Lake Erie College of Osteopathic Medicine (LECOM), Erie, PA, 16509, USA
| | - Istvan Merchenthaler
- Department of Epidemiology and Public Health and Anatomy and Neurobiology, University of Maryland Baltimore, 10 South Pine Street MSTF 977, Baltimore, MD, 21201, USA.
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Rodríguez-Rodríguez A, Lazcano I, Sánchez-Jaramillo E, Uribe RM, Jaimes-Hoy L, Joseph-Bravo P, Charli JL. Tanycytes and the Control of Thyrotropin-Releasing Hormone Flux Into Portal Capillaries. Front Endocrinol (Lausanne) 2019; 10:401. [PMID: 31293518 PMCID: PMC6603095 DOI: 10.3389/fendo.2019.00401] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 06/06/2019] [Indexed: 12/17/2022] Open
Abstract
Central and peripheral mechanisms that modulate energy intake, partition and expenditure determine energy homeostasis. Thyroid hormones (TH) regulate energy expenditure through the control of basal metabolic rate and thermogenesis; they also modulate food intake. TH concentrations are regulated by the hypothalamus-pituitary-thyroid (HPT) axis, and by transport and metabolism in blood and target tissues. In mammals, hypophysiotropic thyrotropin-releasing hormone (TRH) neurons of the paraventricular nucleus of the hypothalamus integrate energy-related information. They project to the external zone of the median eminence (ME), a brain circumventricular organ rich in neuron terminal varicosities and buttons, tanycytes, other glial cells and capillaries. These capillary vessels form a portal system that links the base of the hypothalamus with the anterior pituitary. Tanycytes of the medio-basal hypothalamus express a repertoire of proteins involved in transport, sensing, and metabolism of TH; among them is type 2 deiodinase, a source of 3,3',5-triiodo-L-thyronine necessary for negative feedback on TRH neurons. Tanycytes subtypes are distinguished by position and phenotype. The end-feet of β2-tanycytes intermingle with TRH varicosities and terminals in the external layer of the ME and terminate close to the ME capillaries. Besides type 2 deiodinase, β2-tanycytes express the TRH-degrading ectoenzyme (TRH-DE); this enzyme likely controls the amount of TRH entering portal vessels. TRH-DE is rapidly upregulated by TH, contributing to TH negative feedback on HPT axis. Alterations in energy balance also regulate the expression and activity of TRH-DE in the ME, making β2-tanycytes a hub for energy-related regulation of HPT axis activity. β2-tanycytes also express TRH-R1, which mediates positive effects of TRH on TRH-DE activity and the size of β2-tanycyte end-feet contacts with the basal lamina adjacent to ME capillaries. These end-feet associations with ME capillaries, and TRH-DE activity, appear to coordinately control HPT axis activity. Thus, down-stream of neuronal control of TRH release by action potentials arrival in the external layer of the median eminence, imbricated intercellular processes may coordinate the flux of TRH into the portal capillaries. In conclusion, β2-tanycytes appear as a critical cellular element for the somatic and post-secretory control of TRH flux into portal vessels, and HPT axis regulation in mammals.
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Affiliation(s)
- Adair Rodríguez-Rodríguez
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Iván Lazcano
- Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Juriquilla, Mexico
| | - Edith Sánchez-Jaramillo
- Laboratorio de Neuroendocrinología Molecular, Dirección de Investigaciones en Neurociencias, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, Mexico City, Mexico
| | - Rosa María Uribe
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Lorraine Jaimes-Hoy
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Patricia Joseph-Bravo
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Jean-Louis Charli
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
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