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Katane M, Homma H. Biosynthesis and Degradation of Free D-Amino Acids and Their Physiological Roles in the Periphery and Endocrine Glands. Biol Pharm Bull 2024; 47:562-579. [PMID: 38432912 DOI: 10.1248/bpb.b23-00485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/05/2024]
Abstract
It was long believed that D-amino acids were either unnatural isomers or laboratory artifacts, and that the important functions of amino acids were exerted only by L-amino acids. However, recent investigations have revealed a variety of D-amino acids in mammals that play important roles in physiological functions, including free D-serine and D-aspartate that are crucial in the central nervous system. The functions of several D-amino acids in the periphery and endocrine glands are also receiving increasing attention. Here, we present an overview of recent advances in elucidating the physiological roles of D-amino acids, especially in the periphery and endocrine glands.
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Affiliation(s)
- Masumi Katane
- Medicinal Research Laboratories, Graduate School of Pharmaceutical Sciences, Kitasato University
| | - Hiroshi Homma
- Laboratory of Analytical Chemistry, Graduate School of Pharmaceutical Sciences, Kitasato University
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2
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Siecinski SK, Giamberardino SN, Spanos M, Hauser AC, Gibson JR, Chandrasekhar T, Trelles MDP, Rockhill CM, Palumbo ML, Cundiff AW, Montgomery A, Siper P, Minjarez M, Nowinski LA, Marler S, Kwee LC, Shuffrey LC, Alderman C, Weissman J, Zappone B, Mullett JE, Crosson H, Hong N, Luo S, She L, Bhapkar M, Dean R, Scheer A, Johnson JL, King BH, McDougle CJ, Sanders KB, Kim SJ, Kolevzon A, Veenstra-VanderWeele J, Hauser ER, Sikich L, Gregory SG. Genetic and epigenetic signatures associated with plasma oxytocin levels in children and adolescents with autism spectrum disorder. Autism Res 2023; 16:502-523. [PMID: 36609850 PMCID: PMC10023458 DOI: 10.1002/aur.2884] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 12/19/2022] [Indexed: 01/09/2023]
Abstract
Oxytocin (OT), the brain's most abundant neuropeptide, plays an important role in social salience and motivation. Clinical trials of the efficacy of OT in autism spectrum disorder (ASD) have reported mixed results due in part to ASD's complex etiology. We investigated whether genetic and epigenetic variation contribute to variable endogenous OT levels that modulate sensitivity to OT therapy. To carry out this analysis, we integrated genome-wide profiles of DNA-methylation, transcriptional activity, and genetic variation with plasma OT levels in 290 participants with ASD enrolled in a randomized controlled trial of OT. Our analysis identified genetic variants with novel association with plasma OT, several of which reside in known ASD risk genes. We also show subtle but statistically significant association of plasma OT levels with peripheral transcriptional activity and DNA-methylation profiles across several annotated gene sets. These findings broaden our understanding of the effects of the peripheral oxytocin system and provide novel genetic candidates for future studies to decode the complex etiology of ASD and its interaction with OT signaling and OT-based interventions. LAY SUMMARY: Oxytocin (OT) is an abundant chemical produced by neurons that plays an important role in social interaction and motivation. We investigated whether genetic and epigenetic factors contribute to variable OT levels in the blood. To this, we integrated genetic, gene expression, and non-DNA regulated (epigenetic) signatures with blood OT levels in 290 participants with autism enrolled in an OT clinical trial. We identified genetic association with plasma OT, several of which reside in known autism risk genes. We also show statistically significant association of plasma OT levels with gene expression and epigenetic across several gene pathways. These findings broaden our understanding of the factors that influence OT levels in the blood for future studies to decode the complex presentation of autism and its interaction with OT and OT-based treatment.
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Affiliation(s)
- Stephen K Siecinski
- Duke Molecular Physiology Institute, Duke University School of Medicine, Durham, NC, USA
| | | | - Marina Spanos
- Department of Psychiatry and Behavioral Sciences, Duke University School of Medicine, Durham, NC, USA
| | - Annalise C Hauser
- Duke Molecular Physiology Institute, Duke University School of Medicine, Durham, NC, USA
| | - Jason R Gibson
- Duke Molecular Physiology Institute, Duke University School of Medicine, Durham, NC, USA
| | - Tara Chandrasekhar
- Department of Psychiatry and Behavioral Sciences, Duke University School of Medicine, Durham, NC, USA
| | - M D Pilar Trelles
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Carol M Rockhill
- Department of Psychiatry, Seattle Children’s Hospital and the University of Washington, Seattle, WA, USA
| | - Michelle L Palumbo
- Department of Psychiatry, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | | | | | - Paige Siper
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Mendy Minjarez
- Department of Psychiatry, Seattle Children’s Hospital and the University of Washington, Seattle, WA, USA
| | - Lisa A Nowinski
- Department of Psychiatry, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Sarah Marler
- Department of Psychiatry, Vanderbilt University, Nashville, TN, USA
| | - Lydia C Kwee
- Duke Molecular Physiology Institute, Duke University School of Medicine, Durham, NC, USA
| | | | - Cheryl Alderman
- Department of Psychiatry and Behavioral Sciences, Duke University School of Medicine, Durham, NC, USA
- Duke Clinical Research Institute, Duke University School of Medicine, Durham, NC, USA
| | - Jordana Weissman
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Brooke Zappone
- Department of Psychiatry, Seattle Children’s Hospital and the University of Washington, Seattle, WA, USA
| | - Jennifer E Mullett
- Department of Psychiatry, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Hope Crosson
- Department of Psychiatry, Columbia University, New York, NY, USA
| | - Natalie Hong
- Department of Psychiatry, Columbia University, New York, NY, USA
| | - Sheng Luo
- Duke Clinical Research Institute, Duke University School of Medicine, Durham, NC, USA
- Department of Biostatistics and Bioinformatics, Duke University School of Medicine, Durham, NC, USA
| | - Lilin She
- Duke Clinical Research Institute, Duke University School of Medicine, Durham, NC, USA
| | - Manjushri Bhapkar
- Duke Clinical Research Institute, Duke University School of Medicine, Durham, NC, USA
| | - Russell Dean
- Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Abby Scheer
- Department of Psychiatry and Behavioral Sciences, Duke University School of Medicine, Durham, NC, USA
| | - Jacqueline L Johnson
- Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Bryan H King
- Department of Psychiatry, Seattle Children’s Hospital and the University of Washington, Seattle, WA, USA
| | - Christopher J McDougle
- Department of Psychiatry, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Kevin B Sanders
- Department of Psychiatry, Vanderbilt University, Nashville, TN, USA
| | - Soo-Jeong Kim
- Department of Psychiatry, Seattle Children’s Hospital and the University of Washington, Seattle, WA, USA
| | - Alexander Kolevzon
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | | | - Elizabeth R Hauser
- Duke Molecular Physiology Institute, Duke University School of Medicine, Durham, NC, USA
- Department of Biostatistics and Bioinformatics, Duke University School of Medicine, Durham, NC, USA
| | - Linmarie Sikich
- Department of Psychiatry and Behavioral Sciences, Duke University School of Medicine, Durham, NC, USA
- Duke Clinical Research Institute, Duke University School of Medicine, Durham, NC, USA
| | - Simon G Gregory
- Duke Molecular Physiology Institute, Duke University School of Medicine, Durham, NC, USA
- Department of Neurology, Duke University School of Medicine, Durham, NC, USA
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Royo M, Escolano BA, Madrigal MP, Jurado S. AMPA Receptor Function in Hypothalamic Synapses. Front Synaptic Neurosci 2022; 14:833449. [PMID: 35173598 PMCID: PMC8842481 DOI: 10.3389/fnsyn.2022.833449] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Accepted: 01/03/2022] [Indexed: 12/15/2022] Open
Abstract
AMPA receptors (AMPARs) are critical for mediating glutamatergic synaptic transmission and plasticity, thus playing a major role in the molecular machinery underlying cellular substrates of memory and learning. Their expression pattern, transport and regulatory mechanisms have been extensively studied in the hippocampus, but their functional properties in other brain regions remain poorly understood. Interestingly, electrophysiological and molecular evidence has confirmed a prominent role of AMPARs in the regulation of hypothalamic function. This review summarizes the existing evidence on AMPAR-mediated transmission in the hypothalamus, where they are believed to orchestrate the role of glutamatergic transmission in autonomous, neuroendocrine function, body homeostasis, and social behavior.
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Abdelwahab LA, Galal OO, Abd El-Rahman SS, El-Brairy AI, Khattab MM, El-Khatib AS. Targeting the oxytocin system to ameliorate early life depressive-like behaviors in maternally-separated rats. Biol Pharm Bull 2021; 44:1445-1457. [PMID: 34349049 DOI: 10.1248/bpb.b21-00247] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Oxytocin (OXT) - "the love hormone" - has been involved in the anti-depressant activity of some selective serotonin reuptake inhibitors (SSRIs). The exact mechanism underlying the OXT pathway in depression is not fully clear. This study aimed to investigate the effect of OXT analogue, carbetocin (CBT) and the SSRI, escitalopram (ESCIT) on depressive-like behaviors following maternal separation (MS). It is worthy to mention that intranasal CBT has been approved by FDA for Prader-Willi syndrome. Adolescent Wistar albino maternally-separated rats were given CBT, (100 μg/animal/day via inhalation route), and, ESCIT, (20 mg kg-1, po) either alone or in combination for 7 days. Repeated 3-h MS demonstrated increased immobility time in forced swim test (FST) and decreased locomotor activity in open field test. MS elevated plasma level of adrenocortico-trophic hormone (ACTH) but notably reduced plasma OXT, with no effect on hippocampal OXT-R expression. Following MS, hippocampal contents of 5-hydroxytryptamine receptors (5HT1A-R), serotonin transporter (SERT) were increased. CBT and ESCIT corrected the behavioral dysfunction in FST and suppressed the high levels of ACTH. Additionally, both treatments boosted OXT level, reduced 5HT1A-R and normalized SERT contents, which reflects increased availability of serotonin. Finally, CBT markedly ameliorated the histopathological damage induced by MS and suppressed the increased glial fibrillary acidic protein. CBT and ESCIT manage depressive-like behavior by positively affecting serotonergic and oxytocinergic systems. Targeting OXT system -using CBT- ameliorated depressive like behaviors induced by maternal separation most probably via enhancing OXT plasma levels, attenuating hormonal ACTH and restoring the expression of hippocampal oxytocin and serotonin mechanisms.
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Affiliation(s)
- Lobna A Abdelwahab
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, October University for Modern Sciences and Arts (MSA)
| | - Omneya O Galal
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Ahram Canadian University (ACU)
| | | | - Amany I El-Brairy
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, October University for Modern Sciences and Arts (MSA)
| | - Mahmoud M Khattab
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Cairo University
| | - Aiman S El-Khatib
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Cairo University
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Di Fiore MM, Boni R, Santillo A, Falvo S, Gallo A, Esposito S, Baccari GC. D-Aspartic Acid in Vertebrate Reproduction: Animal Models and Experimental Designs ‡. Biomolecules 2019; 9:biom9090445. [PMID: 31484465 PMCID: PMC6770039 DOI: 10.3390/biom9090445] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 08/29/2019] [Accepted: 09/02/2019] [Indexed: 11/16/2022] Open
Abstract
This article reviews the animal models and experimental designs that have been used during the past twenty years to demonstrate the prominent role played by d-aspartate (d-Asp) in the reproduction of vertebrates, from amphibians to humans. We have tabulated the findings of in vivo and in vitro experiments that demonstrate the effects of d-Asp uptake on hormone production and gametogenesis in vertebrate animal models. The contribution of each animal model to the existing knowledge on the role of d-Asp in reproductive processes has been discussed. A critical analysis of experimental designs has also been carried out. Experiments performed on wild animal species suggest a role of d-Asp in the mechanisms that regulate the reproductive cycle. Several in vivo and in vitro studies carried out on mouse and rat models have facilitated an understanding of the molecular pathways activated by D-Asp in both steroidogenesis and spermatogenesis, with particular emphasis on testosterone biosynthesis. Some attempts using d-Asp for the improvement of reproductive activity in animals of commercial interest have yielded mixed results. The increased transcriptome activity of enzymes and receptors involved in the reproductive activity in d-Asp-treated broiler roosters revealed further details on the mechanism of action of d-Asp on the reproductive processes. The close relationship between d-Asp and reproductive activity has emerged, particularly in relation to its effects exerted on semen quality, proposing therapeutic applications of this amino acid in andrology and in medically-assisted procreation techniques.
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Affiliation(s)
- Maria Maddalena Di Fiore
- Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Università della Campania L. Vanvitelli, Via Vivaldi 43, 81100 Caserta, Italy
| | - Raffaele Boni
- Dipartimento di Scienze, Università della Basilicata, Via dell'Ateneo Lucano 10, 85100 Potenza, Italy
| | - Alessandra Santillo
- Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Università della Campania L. Vanvitelli, Via Vivaldi 43, 81100 Caserta, Italy.
| | - Sara Falvo
- Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Università della Campania L. Vanvitelli, Via Vivaldi 43, 81100 Caserta, Italy
| | - Alessandra Gallo
- Dipartimento di Biologia ed Evoluzione degli Organismi Marini, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Napoli, Italy
| | - Sabrina Esposito
- Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Università della Campania L. Vanvitelli, Via Vivaldi 43, 81100 Caserta, Italy
| | - Gabriella Chieffi Baccari
- Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Università della Campania L. Vanvitelli, Via Vivaldi 43, 81100 Caserta, Italy
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Vilhena-Franco T, Valentim-Lima E, Reis LC, Elias LLK, Antunes-Rodrigues J, Mecawi AS. Role of AMPA and NMDA receptors on vasopressin and oxytocin secretion induced by hypertonic extracellular volume expansion. J Neuroendocrinol 2018; 30:e12633. [PMID: 29998612 DOI: 10.1111/jne.12633] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 07/08/2018] [Indexed: 01/06/2023]
Abstract
Vasopressin (AVP) and oxytocin (OT) are essential for the control of extracellular fluid osmolality and volume. Secretion of these hormones is modulated by several mechanisms, including NMDA and AMPA L-glutamate receptors in magnocellular cells of paraventricular (PVN) and supraoptic (SON) hypothalamic nuclei. Thus, to better understand the participation of L-glutamate on the neuroendocrine control of AVP and OT, this work evaluated the effects of intracerebroventricular (icv) NMDA and AMPA receptor antagonists on plasma AVP and OT levels induced by extracellular volume expansion (EVE). Cannulated rats received icv NMDA (AP5) and AMPA (NBQX) antagonists in 10 and 30nmol/5μl/rat doses and were subjected to either isotonic (0.15 M NaCl, 2ml/100g) or hypertonic (0.30 M NaCl, 2ml/100g) EVE. Blood samples were collected for plasma AVP and OT determination. Isotonic EVE did not change plasma AVP and OT levels, but hypertonic EVE increased both AVP and OT plasma levels. AP5 reduced plasma AVP, but it did not change the OT level induced by hypertonic EVE. On the other hand, NBQX reduced plasma OT, but did not alter the AVP plasma level. Our data shows that L-glutamate controls the secretion of neurohypophyseal hormones through the NMDA receptor for AVP release, and through the AMPA receptor for OT release, both in response to hypertonic EVE. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Tatiane Vilhena-Franco
- Department of Physiology Ribeirão, Preto Medical School, São Paulo University, Ribeirão Preto, São Paulo, Brazil
| | - Evandro Valentim-Lima
- Department of Physiological Sciences, Institute of Biological and Health Sciences, Federal Rural University of Rio de Janeiro, Seropédica, Rio de Janeiro, Brazil
| | - Luís C Reis
- Department of Physiological Sciences, Institute of Biological and Health Sciences, Federal Rural University of Rio de Janeiro, Seropédica, Rio de Janeiro, Brazil
| | - Lucila L K Elias
- Department of Physiology Ribeirão, Preto Medical School, São Paulo University, Ribeirão Preto, São Paulo, Brazil
| | - Jose Antunes-Rodrigues
- Department of Physiology Ribeirão, Preto Medical School, São Paulo University, Ribeirão Preto, São Paulo, Brazil
| | - André S Mecawi
- Department of Physiological Sciences, Institute of Biological and Health Sciences, Federal Rural University of Rio de Janeiro, Seropédica, Rio de Janeiro, Brazil
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Jalali M, Zendehdel M, Babapour V, Gilanpour H. Interaction Between Central Oxytocinergic and Glutamatergic Systems on Food Intake in Neonatal Chicks: Role of NMDA and AMPA Receptors. Int J Pept Res Ther 2017. [DOI: 10.1007/s10989-017-9664-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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8
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Teng BL, Nonneman RJ, Agster KL, Nikolova VD, Davis TT, Riddick NV, Baker LK, Pedersen CA, Jarstfer MB, Moy SS. Prosocial effects of oxytocin in two mouse models of autism spectrum disorders. Neuropharmacology 2013; 72:187-96. [PMID: 23643748 DOI: 10.1016/j.neuropharm.2013.04.038] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Revised: 03/23/2013] [Accepted: 04/22/2013] [Indexed: 12/17/2022]
Abstract
Clinical evidence suggests that oxytocin treatment improves social deficits and repetitive behavior in autism spectrum disorders (ASDs). However, the neuropeptide has a short plasma half-life and poor ability to penetrate the blood-brain barrier. In order to facilitate the development of more bioavailable oxytocinergic compounds as therapeutics to treat core ASD symptoms, small animal models must be validated for preclinical screens. This study examined the preclinical utility of two inbred mouse strains, BALB/cByJ and C58/J, that exhibit phenotypes relevant to core ASD symptoms. Mice from both strains were intraperitoneally administered oxytocin, using either acute or sub-chronic regimens. Acute oxytocin did not increase sociability in BALB/cByJ; however, sub-chronic oxytocin had significant prosocial effects in both BALB/cByJ and C58/J. Increased sociability was observed 24 h following the final oxytocin dose in BALB/cByJ, while prosocial effects of oxytocin emerged 1-2 weeks post-treatment in C58/J. Furthermore, acute oxytocin decreased motor stereotypy in C58/J and did not induce hypoactivity or anxiolytic-like effects in an open field test. This study demonstrates that oxytocin administration can attenuate social deficits and repetitive behavior in mouse models of ASD, dependent on dose regimen and genotype. These findings provide validation of the BALB/cByJ and C58/J models as useful platforms for screening novel drugs for intervention in ASDs and for elucidating the mechanisms contributing to the prosocial effects of oxytocin.
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Affiliation(s)
- Brian L Teng
- Carolina Institute for Developmental Disabilities, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA.
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Katane M, Homma H. D-Aspartate--an important bioactive substance in mammals: a review from an analytical and biological point of view. J Chromatogr B Analyt Technol Biomed Life Sci 2011; 879:3108-21. [PMID: 21524944 DOI: 10.1016/j.jchromb.2011.03.062] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Revised: 03/23/2011] [Accepted: 03/30/2011] [Indexed: 01/08/2023]
Abstract
It was long believed that D-amino acids were either unnatural isomers or laboratorial artifacts and that the important functions of amino acids were exerted only by l-amino acids. However, recent investigations have shown that a variety of D-amino acids are present in mammals and that they play important roles in physiological functions in the body. Among the free d-amino acids that have been identified in mammals, D-aspartate (D-Asp) has been shown to play a crucial role in the neuroendocrine and endocrine systems as well as in the central nervous system. Here, we present an overview of recent studies of free D-Asp, focusing on the analytical methods in real biological matrices, expression and localization in tissues and cells, biological and physiological activities, biosynthesis, degradation, cellular transport, and possible relevance to disease. In addition to frequently used techniques for the enantiomeric determination of amino acids, including high-performance liquid chromatography and enzymatic methods, the recent development of analytical methods is also described.
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Affiliation(s)
- Masumi Katane
- Laboratory of Biomolecular Science, Department of Pharmaceutical Life Sciences, Kitasato University, 5-9-1 Shirokane, Tokyo 108-8641, Japan
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Popesku JT, Mennigen JA, Chang JP, Trudeau VL. Dopamine D1 receptor blockage potentiates AMPA-stimulated luteinising hormone release in the goldfish. J Neuroendocrinol 2011; 23:302-9. [PMID: 21276102 DOI: 10.1111/j.1365-2826.2011.02114.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Previous microarray analyses of the goldfish hypothalamus led us to hypothesise that dopamine could potentially inhibit the excitatory effects of glutamate on luteinising hormone (LH). Post-spawning female goldfish were pre-treated (-4.5 h) with either saline (C; control), SCH 23390 (S; D(1) -receptor antagonist) or sulpiride (L; D(2) -receptor antagonist), followed by an i.p. injection, at -0.5 h, of saline or the glutamate agonist AMPA (A, SA or LA). Blood, hypothalamus and telencephalon tissues were collected. Serum LH was not affected in the S, L, A, or LA groups relative to control as determined by radioimmunoassay. The SA group, however, showed a 289% (P<0.0005) increase in serum LH compared to either treatment alone or control. Real-time reverse transcriptase-polymerase chain reaction identified the mRNAs for ionotropic (Gria2a, Gria4) glutamate receptor subunits, activin βa, isotocin, and cGnRH-II as being significantly affected by some of the treatments. The same experiment conducted with sexually-regressed female fish showed a very different LH profile, indicating that this mechanism is seasonally-dependent. We also show that i.p. injection of 1 μg/g isotocin was able to increase LH levels by 167% in sexually regressed female fish relative to controls. Taken together, these results demonstrate that blockage of the D(1) receptor primes post-spawning goldfish for AMPA-stimulated LH release, and provides further insights into the central regulation of reproduction.
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Affiliation(s)
- J T Popesku
- Centre for Advanced Research in Environmental Genomics (CAREG), Department of Biology, University of Ottawa, Ottawa, Canada
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Yamamoto A, Tanaka H, Ishida T, Horiike K. D-aspartate oxidase localisation in pituitary and pineal glands of the female pig. J Neuroendocrinol 2010; 22:1165-72. [PMID: 20819121 DOI: 10.1111/j.1365-2826.2010.02066.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Recent evidence has shown that D-aspartate modulates hormone secretion in the vertebral neuroendocrine system. Because only D-aspartate oxidase (DDO) can degrade D-aspartate, we determined DDO localisation in the pituitary and pineal glands to elucidate the control mechanisms of local D-aspartate concentration. Brain tissues and pituitary and pineal glands of the female pigs contained a similar DDO activity of 0.38-0.66 U/g protein. However, approximately ten-fold higher concentrations of D-aspartate (0.27-0.35 μmol/g protein) were found in both glands. To determine the distribution of immunoreactive DDO, we made a rabbit polyclonal antibody specific to porcine DDO using a recombinant porcine enzyme. DDO immunoreactivity was found in the cytoplasm of a subgroup of cells in the anterior and intermediate lobes, in a part of nerve processes and terminals in the posterior lobe, and in the cytoplasm of a small group of pinealocytes. We used dual-label immunocytochemistry to determine which pituitary hormones colocalise with DDO, and whether DDO and D-aspartate immunoreactivity is reciprocal. In the pituitary gland, almost all proopiomelanocortin-positive cells colocalised DDO, whereas only growth hormone-positive cells colocalised D-aspartate. D-aspartate immunoreactivity was not detected where DDO immunoreactivity was found. The present study suggests that DDO plays important roles to prevent undesirable off-target action of D-aspartate by strictly controlling local D-aspartate concentration in the pituitary and pineal glands.
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Affiliation(s)
- A Yamamoto
- Department of Biochemistry and Molecular Biology, Shiga University of Medical Science, Ohtsu, Shiga, Japan
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Yamamoto A, Tanaka H, Ishida T, Horiike K. Immunohistochemical localization of d-aspartate oxidase in porcine peripheral tissues. Amino Acids 2010; 41:529-36. [DOI: 10.1007/s00726-010-0785-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2010] [Accepted: 10/06/2010] [Indexed: 11/29/2022]
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13
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Irani BG, Donato J, Olson DP, Lowell BB, Sacktor TC, Reyland ME, Tolson KP, Zinn AR, Ueta Y, Sakata I, Zigman JM, Elias CF, Clegg DJ. Distribution and neurochemical characterization of protein kinase C-theta and -delta in the rodent hypothalamus. Neuroscience 2010; 170:1065-79. [PMID: 20691763 DOI: 10.1016/j.neuroscience.2010.07.064] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2010] [Revised: 07/29/2010] [Accepted: 07/31/2010] [Indexed: 11/24/2022]
Abstract
PKC-theta (PKC-θ), a member of the novel protein kinase C family (nPKC), regulates a wide variety of functions in the periphery. However, its presence and role in the CNS has remained largely unknown. Recently, we demonstrated the presence of PKC-θ in the arcuate hypothalamic nucleus (ARC) and knockdown of PKC-θ from the ARC protected mice from developing diet-induced obesity. Another isoform of the nPKC group, PKC-delta (PKC-δ), is expressed in several non-hypothalamic brain sites including the thalamus and hippocampus. Although PKC-δ has been implicated in regulating hypothalamic glucose homeostasis, its distribution in the hypothalamus has not previously been described. In the current study, we used immunohistochemistry to examine the distribution of PKC-θ and -δ immunoreactivity in rat and mouse hypothalamus. We found PKC-θ immunoreactive neurons in several hypothalamic nuclei including the ARC, lateral hypothalamic area, perifornical area and tuberomammillary nucleus. PKC-δ immunoreactive neurons were found in the paraventricular and supraoptic nuclei. Double-label immunohistochemisty in mice expressing green fluorescent protein either with the long form of leptin receptor (LepR-b) or in orexin (ORX) neurons indicated that PKC-θ is highly colocalized in lateral hypothalamic ORX neurons but not in lateral hypothalamic LepR-b neurons. Double-label immunohistochemistry in oxytocin-enhanced yellow fluorescent protein mice or arginine vasopressin-enhanced green fluorescent protein (AVP-EGFP) transgenic rats revealed a high degree of colocalization of PKC-δ within paraventricular and supraoptic oxytocin neurons but not the vasopressinergic neurons. We conclude that PKC-θ and -δ are expressed in different hypothalamic neuronal populations.
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Affiliation(s)
- B G Irani
- Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-8854, USA
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14
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D-Aspartate Oxidase: The Sole Catabolic Enzyme Acting on Free D-Aspartate in Mammals. Chem Biodivers 2010; 7:1435-49. [DOI: 10.1002/cbdv.200900250] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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15
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Salmina AB, Lopatina O, Ekimova MV, Mikhutkina SV, Higashida H. CD38/cyclic ADP-ribose system: a new player for oxytocin secretion and regulation of social behaviour. J Neuroendocrinol 2010; 22:380-92. [PMID: 20141572 DOI: 10.1111/j.1365-2826.2010.01970.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Oxytocin is important for regulating a number of physiological processes. Disruption of the secretion, metabolism or action of oxytocin results in an impairment of reproductive function, social and sexual behaviours, and stress responses. This review discusses current views on the regulation and autoregulation of oxytocin release in the hypothalamic-neurohypophysial system, with special focus on the activity of the CD38/cADP-ribose system as a new component in this regulation. Data from our laboratories indicate that an impairment of this system results in alterations of oxytocin secretion and abnormal social behaviour, thus suggesting new clues that help in our understanding of the pathogenesis of neurodevelopmental disorders.
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Affiliation(s)
- A B Salmina
- Department of Biochemistry, Medical, Pharmaceutical and Toxicological Chemistry, Krasnoyarsk State Medical University, Krasnoyarsk 660022, Russia.
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16
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Durand D, Pampillo M, Caruso C, Lasaga M. Role of metabotropic glutamate receptors in the control of neuroendocrine function. Neuropharmacology 2008; 55:577-83. [PMID: 18616955 DOI: 10.1016/j.neuropharm.2008.06.022] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2008] [Revised: 05/23/2008] [Accepted: 06/12/2008] [Indexed: 11/25/2022]
Abstract
Glutamate exerts its effects through binding and activation of two classes of specific receptors: ionotropic (iGluRs) and metabotropic (mGluRs). Group I mGluR includes mGluR1 and mGluR5 subtypes, group II includes mGluR2 and mGluR3 subtypes and group III includes the subtypes mGluR 4, 6, 7 and 8. Glutamate and its receptors are found in all key hypothalamic areas critically involved in reproduction and neuroendocrine function. To date, considerable data support an important role for iGluRs in the control of neuroendocrine function; however, the role of mGluRs as regulators of hypothalamic-pituitary function has not been clearly elucidated. mGluRs could be exerting a fine tune on the release of hypothalamic factors that regulate hormone release such as Substance P, GABA, alpha-MSH and CRH. Group II mGluR exert a direct inhibitory effect on anterior pituitary prolactin and GH secretion. Moreover, some group II mGluR agonists, like LY 354,740 and LY 379,268, can modulate PRL secretion from the anterior pituitary through their actions as dopamine receptor agonists. Evidence suggests a role for group III mGluR subtypes in stress-related behavioral disorders. Several reports indicate that selective ligands for mGluR subtypes have potential for the treatment of a wide variety of neurological and psychiatric disorders, including depression, anxiety disorders, schizophrenia, epilepsy and Alzheimer's disease among others. Since converging lines of evidence suggest a role for mGluRs subtypes in neuroendocrine regulation of hormone secretion, mGluRs neuroendocrine actions must be taken in consideration to insure proper treatment of these diseases. Moreover, discovery of selective agonists provides an opportunity to investigate the physiological role of mGluR subtypes and to directly test the neuroendocrine actions of mGluRs. Finally, mGluRs selective agonists may have an impact in the treatment of conditions involving chronic stress, such as depression and anxiety disorders, since they regulate neuroendocrine stress circuits involving the HPA axis and stress-sensitive hormones such as oxytocin and prolactin. This review aims to provide a survey of our current understanding of the effects of mGluR activation on neuroendocrine function.
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Affiliation(s)
- Daniela Durand
- Research Center in Reproduction, School of Medicine, University of Buenos Aires, Paraguay 2155, Piso 10, 1121 Buenos Aires, Argentina
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17
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Funakoshi M, Sekine M, Katane M, Furuchi T, Yohda M, Yoshikawa T, Homma H. Cloning and functional characterization of Arabidopsis thaliana D-amino acid aminotransferase--D-aspartate behavior during germination. FEBS J 2008; 275:1188-200. [PMID: 18318836 DOI: 10.1111/j.1742-4658.2008.06279.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The understanding of D-amino acid metabolism in higher plants lags far behind that in mammals, for which the biological functions of these unique amino acids have already been elucidated. In this article, we report on the biochemical behavior of D-amino acids (particularly D-Asp) and relevant metabolic enzymes in Arabidopsis thaliana. During germination and growth of the plant, a transient increase in D-Asp levels was observed, suggesting that D-Asp is synthesized in the plant. Administration of D-Asp suppressed growth, although the inhibitory mechanism responsible for this remains to be clarified. Exogenous D-Asp was efficiently incorporated and metabolized, and was converted to other D-amino acids (D-Glu and D-Ala). We then studied the related metabolic enzymes, and consequently cloned and characterized A. thaliana D-amino acid aminotransferase, which is presumably involved in the metabolism of D-Asp in the plant by catalyzing transamination between D-amino acids. This is the first report of cDNA cloning and functional characterization of a D-amino acid aminotransferase in eukaryotes. The results presented here provide important information for understanding the significance of D-amino acids in the metabolism of higher plants.
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Affiliation(s)
- Miya Funakoshi
- School of Pharmaceutical Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, Japan
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18
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Katane M, Seida Y, Sekine M, Furuchi T, Homma H. Caenorhabditis eleganshas two genes encoding functionald-aspartate oxidases. FEBS J 2006; 274:137-49. [PMID: 17140416 DOI: 10.1111/j.1742-4658.2006.05571.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Four cDNA clones that were annotated in the database as encoding d-amino acid oxidase (DAAO) or d-aspartate oxidase (DASPO) were isolated by RT-PCR from Caenorhabditis elegans RNA. The proteins (Y69Ap, C47Ap, F18Ep, and F20Hp) encoded by the cloned cDNAs were expressed in Escherichia coli as recombinant proteins with an N-terminal His-tag. All proteins except F20Hp were recovered in the soluble fractions. The recombinant Y69Ap has functional DAAO activity, as it can deaminate neutral and basic d-amino acids, whereas the recombinants C47Ap and F18Ep have functional DASPO activities, as they can deaminate acidic d-amino acids. Additional experiments using purified recombinant proteins revealed that Y69Ap deaminates d-Arg more efficiently than d-Ala and d-Met, and that C47Ap and F18Ep show distinct kinetic properties against d-Asp, d-Glu, and N-methyl-d-Asp. This is the first time that cDNA cloning of invertebrate DAAO and DASPO genes has been reported. In addition, our study reveals for the first time that C. elegans has at least two genes encoding functional DASPOs and one gene encoding DAAO, although it had previously been thought that organisms only bear one copy each of these genes. The two C. elegans DASPOs differ in their substrate specificities and possibly also in their subcellular localization.
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Affiliation(s)
- Masumi Katane
- Laboratory of Biomolecular Science, School of Pharmaceutical Sciences, Kitasato University, Tokyo, Japan
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19
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Kawasaki A, Shutoh F, Nogami H, Hisano S. VGLUT2 expression is up-regulated in neurohypophysial vasopressin neurons of the rat after osmotic stimulation. Neurosci Res 2006; 56:124-7. [PMID: 16842872 DOI: 10.1016/j.neures.2006.05.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2006] [Revised: 05/18/2006] [Accepted: 05/22/2006] [Indexed: 11/21/2022]
Abstract
A second vesicular glutamate transporter (VGLUT2) is detected in magnocellular neurons in the rat hypothalamus. The present study revealed what phenotype of neurons express VGLUT2 mRNA by the histological method. We found that most vasopressin (VP) neurons and several oxytocin (OT) neurons express VGLUT2 mRNA. VGLUT2 gene expression in VP and OT neurons is enhanced with osmotic challenges. In the neurohypophysis, VGLUT2-staining in OT terminals was reduced with osmotic stimulation. These results indicate that VGLUT2 is principally expressed in VP neurons and also in some OT neurons and that VGLUT2 in VP and OT neurons is involved in osmotic regulation.
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Affiliation(s)
- Akiko Kawasaki
- Laboratory of Neuroendocrinology, Institute of Basic Medical Sciences, University of Tsukuba, Tsukuba, Japan.
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20
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Zehra Minbay F, Eyigor O, Cavusoglu I. Kainic acid activates oxytocinergic neurons through non-nmda glutamate receptors. Int J Neurosci 2006; 116:587-600. [PMID: 16644519 DOI: 10.1080/00207450600592123] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
The present study assessed if kainic acid activates oxytocinergic neurons and this activation is blocked by 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX). Dual immunohistochemistry for oxytocin and c-Fos showed that oxytocin neurons in SON and PVN express c-Fos following kainic acid administration, a significant increase when compared to the control group. Administration of CNQX prior to kainic acid caused a significant reduction. The results suggested the participation of non-NMDA receptors in the regulation of oxytocin neurons because the administration of kainic acid activates these neurons and this activation is blocked by CNQX administration.
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Affiliation(s)
- Fatma Zehra Minbay
- Department of Histology and Embryology, Uludag University Faculty of Medicine, Bursa, Turkey.
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21
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Homma H. Biochemistry of D-aspartate in mammalian cells. Amino Acids 2006; 32:3-11. [PMID: 16755369 DOI: 10.1007/s00726-006-0354-6] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2006] [Accepted: 01/10/2006] [Indexed: 12/23/2022]
Abstract
Recent investigations have shown that D-aspartate (D-Asp) plays an important physiological role(s) in the mammalian body. Here, several recent studies of free D-Asp metabolism in mammals, focusing on cellular localization in tissues, intracellular localization, biosynthesis, efflux, uptake and degradation are reviewed. D-Asp in mammalian tissues is present in specific cells, indicating the existence of specific molecular components that regulate D-Asp levels and localization in tissues. In the rat pheochromocytoma cell line (PC12) and its subclones, D-Asp is synthesized intracellularly, most likely by Asp racemase(s). Endogenous D-Asp apparently has two different intracellular localization patterns: cytoplasmic and vesicular. In PC12 cells, D-Asp release can occur through three distinct pathways: 1) spontaneous, continuous release of cytoplasmic D-Asp, which is not associated with a specific stimulus; 2) release of cytoplasmic D-Asp via a volume-sensitive organic anion channel that connects the cytoplasm and extracellular space; 3) exocytotic discharge of vesicular D-Asp. Under certain conditions, D-Asp can be released via a mechanism that involves the L-Glu transporter. D-Asp is thus apparently in dynamic flux at the cellular level to carry out its physiological function(s) in mammals.
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Affiliation(s)
- H Homma
- Laboratory of Biomolecular Science, School of Pharmaceutical Sciences, Kitasato University, Tokyo, Japan.
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22
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Koyama H, Adachi M, Sekine M, Katane M, Furuchi T, Homma H. Cytoplasmic localization and efflux of endogenous d-aspartate in pheochromocytoma 12 cells. Arch Biochem Biophys 2006; 446:131-9. [PMID: 16427600 DOI: 10.1016/j.abb.2005.12.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2005] [Revised: 12/09/2005] [Accepted: 12/15/2005] [Indexed: 11/16/2022]
Abstract
In our previous reports [Z. Long, H. Homma, J.-A. Lee, T. Fukushima, T. Santa, T. Iwatsubo, R. Yamada, K. Imai, FEBS Lett. 434 (1998) 231-235; Z. Long, M. Sekine, M. Adachi, T. Furuchi, K. Imai, N. Nimura, H. Homma, Arch. Biochem. Biophys. 404 (2002) 92-97], we demonstrated for the first time that D-aspartate (D-Asp) is actually synthesized in cultured mammalian cells such as PC12, MPT1, and GH3 cells. After its synthesis, this unique amino acid is spontaneously and continuously released into the extracellular space during cell culture. In the current study, we characterized two different types of D-Asp efflux in PC12 cells. One is a spontaneous and continuous form of release of cytoplasmic origin that does not involve exocytotic efflux of vesicular origin. Endogenous D-Asp is predominantly localized to the cytoplasm of cells, and this form of D-Asp release presents a striking contrast to exocytotic, quantal discharge of vesicular dopamine. The other form of efflux is also of cytoplasmic origin and occurs through volume-sensitive organic anion channels that are opened upon hyposmotic stimuli. Interestingly, this latter form of efflux is potentiated by acetylcholine stimulation.
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Affiliation(s)
- H Koyama
- Laboratory of Biomolecular Science, School of Pharmaceutical Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
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23
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Caruso C, Durand D, Watanobe H, Lasaga M. NMDA and group I metabotropic glutamate receptors activation modulates substance P release from the arcuate nucleus and median eminence. Neurosci Lett 2005; 393:60-4. [PMID: 16226374 DOI: 10.1016/j.neulet.2005.09.042] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2005] [Revised: 09/14/2005] [Accepted: 09/16/2005] [Indexed: 10/25/2022]
Abstract
Glutamate participates in the regulation of secretion of several neuropeptides, including substance P (SP). Glutamate acts through ionotropic (iGluR) and metabotropic (mGluR) receptors. We have investigated whether glutamate receptor agonists and antagonists could affect SP release from the arcuate nucleus and the median eminence (ARC/ME). An increase in SP-like immunoreactivity (SP-LI) release from ARC/ME was induced by glutamate and N-methyl-D-aspartate (NMDA). This increase was prevented by D-(-)-2-amino-5-phosphono pentanoic acid (DAP5) (0.1mM), a specific NMDA antagonist and by (RS)-1-aminoindan-1,5-dicarboxylic acid (AIDA) (0.1 mM), a selective antagonist of group I mGluR. The selective non-NMDA receptor antagonist 6,7-dinitroquinoxaline-2,3(1H-4H)-dione (DNQX) (0.1mM) and (RS)-alpha-methyl-4-tetrazolylphenylglycine (MTPG) (0.1 mM), a group II and III mGluRs antagonist, did not affect the stimulatory effect of glutamate. A group I selective agonist, (S)-3,5-dihydroxyphenylglycine (DHPG) induced a significant increase in SP-LI release. Supporting the participation of nitric oxide (NO) in the effect of glutamate on SP-LI release, NAME (0.5 mM), a NO synthase inhibitor, reduced the glutamate-induced increase in SP-LI release from ARC/ME. Similarly, glutamate did not induce an increase in SP-LI release in the presence of meloxicam (0.1 mM) (a cyclooxygenase-2 (COX-2) specific inhibitor) indicating that prostaglandins production may also be involved in the glutamate effect. These data indicate that glutamate increases SP-LI release from the ARC/ME by acting through NMDA and group I mGluRs in the male rat. This stimulatory effect could be mediated by nitric oxide and prostaglandin production.
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Affiliation(s)
- Carla Caruso
- Centro de Investigaciones en Reproducción, School of Medicine, University of Buenos Aires, Paraguay 2155, Piso 10, C1121ABG, Argentina
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24
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Kawasaki A, Hoshi K, Kawano M, Nogami H, Yoshikawa H, Hisano S. Up-regulation of VGLUT2 expression in hypothalamic-neurohypophysial neurons of the rat following osmotic challenge. Eur J Neurosci 2005; 22:672-80. [PMID: 16101749 DOI: 10.1111/j.1460-9568.2005.04240.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A second vesicular glutamate transporter (VGLUT2) has been reported to be expressed in neurosecretory neurons of the hypothalamic-neurohypophysial system. To study its role in the neurosecretory neurons, we evaluated the expression of the VGLUT2 gene in the paraventricular (PVN) and supraoptic (SON) nuclei as well as the immunoreactivity in the neurohypophysis under euhydrated and chronic hyperosmotic conditions with in situ hybridization and immunohistochemistry. The intensity of hybridization signals in the PVN, SON and thalamus of rats subjected to water deprivation for 7 days, or drinking 2% NaCl for 4 or 7 days, was compared with that of euhydrated rats (control). The overall intensity in the entire PVN or SON, but not the thalamus, was higher in osmotically stimulated rats than in controls. Within the PVN, a significantly higher intensity of signals than that of controls was found only in the dorsolateral posterior magnocellular region in 4-day salt-loaded rats and in all subregions in water-deprived or 7-day salt-loaded rats. The intensity in the SON was higher in the stimulated rats than in controls, regardless of subregions. In the neurohypophysis, VGLUT2 staining was frequently localized in vasopressin terminals of control rats and was apparently reduced in stimulated rats. These results indicate that VGLUT2 is principally expressed in magnocellular vasopressin neurons, suggesting some local effect of intrinsic glutamate on neurohypophysial hormone secretion.
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Affiliation(s)
- Akiko Kawasaki
- Laboratory of Neuroendocrinology, Institute of Basic Medical Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
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25
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Koyama H, Sekine M, Furuchi T, Katane M, Nimura N, Shimamoto K, Nakajima T, Homma H. A novel L-glutamate transporter inhibitor reveals endogenous D-aspartate homeostasis in rat pheochromocytoma MPT1 cells. Life Sci 2005; 76:2933-44. [PMID: 15820504 DOI: 10.1016/j.lfs.2004.10.057] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2004] [Accepted: 10/26/2004] [Indexed: 11/20/2022]
Abstract
We previously reported for the first time that D-aspartate (D-Asp) is biosynthesized by cultured mammalian cells such as pheochromocytoma (PC)12 cells and its subclone MPT1 (FEBS Lett. 434 (1998) 231, Arch. Biochem. Biophys. 404 (2002) 92). We speculated that D-Asp levels in the intra- and extracellular spaces of the cultured cells are maintained in a dynamic state of homeostasis. To test this here, we utilized a novel and potent L-Glu transporter inhibitor, TFB-TBOA. This inhibitor proved to be a genuine nontransportable blocker of the transporter even during long periods of culture. Use of this inhibitor with MPT1 cells confirmed that D-Asp levels are in a dynamic steady state where it is constantly released into the extracellular space by a yet undefined mechanism as well as being constantly and intensively taken up by the cells via the L-Glu transporter. We estimated the rate with which D-Asp is constitutively released from MPT1 cells is approx. 3.8 pmol/h/1x10(5) cells.
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Affiliation(s)
- Hayato Koyama
- School of Pharmaceutical Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
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26
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Adachi M, Koyama H, Long Z, Sekine M, Furuchi T, Imai K, Nimura N, Shimamoto K, Nakajima T, Homma H. l-Glutamate in the extracellular space regulates endogenous d-aspartate homeostasis in rat pheochromocytoma MPT1 cells. Arch Biochem Biophys 2004; 424:89-96. [PMID: 15019840 DOI: 10.1016/j.abb.2004.01.016] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2003] [Revised: 01/24/2004] [Indexed: 12/25/2022]
Abstract
In previous studies [FEBS Lett. 434 (1998) 231, Arch. Biochem. Biophys. 404 (2002) 92], we demonstrated for the first time that D-aspartate (D-Asp) is synthesized in cultured mammalian cell lines, such as pheochromocytoma 12 (PC12) and its subclone, MPT1. Our current focus is analysis of the dynamics of D-Asp homeostasis in these cells. In this communication, we show that L-glutamate (Glu) and L-Glu transporter substrates in the extracellular space regulate the homeostasis of endogenous D-Asp in MPT1 cells. D-Asp is apparently in dynamic homeostasis, whereby endogenous D-Asp is constantly released into the extracellular space by an undefined mechanism, and continuously and intensively taken up into cells by an L-Glu transporter. Under these conditions, L-Glu and its transporter substrates in the medium may competitively inhibit the uptake of D-Asp via the transporter, resulting in accumulation of the amino acid in the extracellular space. We additionally demonstrate that DL-TBOA, a well-established L-Glu transporter inhibitor, is taken up by the transporter during long time intervals, but not on a short time-scale.
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Affiliation(s)
- Minako Adachi
- School of Pharmaceutical Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
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27
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D'Aniello A, Spinelli P, De Simone A, D'Aniello S, Branno M, Aniello F, Fisher GH, Di Fiore MM, Rastogi RK. Occurrence and neuroendocrine role ofD-aspartic acid andN-methyl-D-aspartic acid inCiona intestinalis. FEBS Lett 2003; 552:193-8. [PMID: 14527686 DOI: 10.1016/s0014-5793(03)00921-9] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Probes for the occurrence of endogenous D-aspartic acid (D-Asp) and N-methyl-D-aspartic acid (NMDA) in the neural complex and gonads of a protochordate, the ascidian Ciona intestinalis, have confirmed the presence of these two excitatory amino acids and their involvement in hormonal activity. A hormonal pathway similar to that which occurs in vertebrates has been discovered. In the cerebral ganglion D-Asp is synthesized from L-Asp by an aspartate racemase. Then, D-Asp is transferred through the blood stream into the neural gland where it gives rise to NMDA by means of an NMDA synthase. NMDA, in turn, passes from the neuronal gland into the gonads where it induces the synthesis and release of a gonadotropin-releasing hormone (GnRH). The GnRH in turn modulates the release and synthesis of testosterone and progesterone in the gonads, which are implicated in reproduction.
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Affiliation(s)
- Antimo D'Aniello
- Laboratory of Neurobiology, Stazione Zoologica 'A. Dohrn', Villa Comunale, 80121 Naples, Italy.
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28
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Currás-Collazo MC, Gillard ER, Jin J, Pandika J. Vasopressin and oxytocin decrease excitatory amino acid release in adult rat supraoptic nucleus. J Neuroendocrinol 2003; 15:182-90. [PMID: 12535160 DOI: 10.1046/j.1365-2826.2003.00976.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Oxytocin and vasopressin reduce the amplitude of excitatory postsynaptic responses in magnocellular neuroendocrine cells of the supraoptic nucleus (SON). To test whether synaptic glutamate release is modulated by these neuropeptides, we examined the combined effect of vasopressin and oxytocin on depolarization-induced glutamate and aspartate release from acutely dissected rat SON or fronto-parietal cortex punches. Glutamate release was stimulated with 60 mm K+ for 5-10 min and measured using ion exchange chromatography or high-performance liquid chromatography. During depolarization with high K+, extracellular glutamate levels increased, on average, to 204% of control values. In the presence of vasopressin/oxytocin, K+-stimulated glutamate and aspartate release were significantly reduced by 34% and 62%, respectively, in the SON. Treatment with the aminopeptidase inhibitor amastatin did not mimic the effects of exogenous vasopressin/oxytocin on glutamate or aspartate release, suggesting that, under the conditions tested here, amastatin treatment may produce more complex effects. The effects of exogenous neuropeptides are likely mediated by oxytocin and/or vasopressin receptors, as the oxytocin- and V1a-receptor antagonist, Manning Compound (10-100 micro m), partially reversed the effects of vasopressin/oxytocin on SON glutamate release. In contrast, in cortical punches, glutamate release was enhanced by high K+, but vasopressin/oxytocin did not significantly reduce glutamate/aspartate release, consistent with the relatively sparse distribution of vasopressin/oxytocin receptors in fronto-parietal cortex. These findings suggest that locally released oxytocin and vasopressin may autoregulate SON magnocellular neuroendocrine cell activity in part by modulating the release of excitatory amino acids from afferent terminals targeting these cells and/or from other cellular sources.
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Affiliation(s)
- M C Currás-Collazo
- Department of Cell Biology and Neuroscience, University of California, Riverside, California, USA.
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Pampillo M, Scimonelli T, Duvilanski BH, Celis ME, Seilicovich A, Lasaga M. The activation of metabotropic glutamate receptors differentially affects GABA and alpha-melanocyte stimulating hormone release from the hypothalamus and the posterior pituitary of male rats. Neurosci Lett 2002; 327:95-8. [PMID: 12098644 DOI: 10.1016/s0304-3940(02)00386-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The aim of the present study was to investigate the effect of metabotropic glutamate receptor (mGluR) activation on gamma-aminobutyric acid (GABA) and alpha-melanocyte stimulating hormone (alpha-MSH) release from hypothalamic fragments and posterior pituitaries. The actions of a number of subtype-selective mGluR agonists were monitored. A group I mGluR agonist, (S)-3-hydroxyphenylglycine (3-HPG; 0.5 mM), decreased K+-induced hypothalamic GABA release. (RS)-1-Aminoindan-1,5-dicarboxylic acid (AIDA), a specific group I mGluR antagonist (0.2 mM), blocked the effect of 3-HPG. (2S, 1'S, 2'S)-2-(Carboxycyclopropyl) glycine (L-CCG-I) and L-serine-O-phosphate (L-SOP; 0.01-1 mM), agonists of group II and III mGluRs, respectively, did not modify hypothalamic evoked GABA release. Group I mGluR activation decreased, whereas group III increased and group II induced no changes in GABA release from the posterior pituitary. 3-HPG (1 mM) and L-CCG-I (0.1 mM) decreased, whereas L-SOP (0.01-0.1 mM) did not change alpha-MSH release from hypothalamic fragments. No agonists of the three mGluR groups modified alpha-MSH release from the posterior pituitary. These results indicate that activation of mGluRs differentially affects GABA and alpha-MSH release from the hypothalamus and the posterior pituitary.
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Affiliation(s)
- Macarena Pampillo
- Centro de Investigaciones en Reproducción, Facultad de Medicina, Universidad de Buenos Aires, Piso 10, Buenos Aires, Argentina
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