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Szabó P, Bonet S, Hetényi R, Hanna D, Kovács Z, Prisztóka G, Križalkovičová Z, Szentpéteri J. Systematic review: pain, cognition, and cardioprotection-unpacking oxytocin's contributions in a sport context. Front Physiol 2024; 15:1393497. [PMID: 38915776 PMCID: PMC11194439 DOI: 10.3389/fphys.2024.1393497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Accepted: 05/13/2024] [Indexed: 06/26/2024] Open
Abstract
Introduction This systematic review investigates the interplay between oxytocin and exercise; in terms of analgesic, anti-inflammatory, pro-regenerative, and cardioprotective effects. Furthermore, by analyzing measurement methods, we aim to improve measurement validity and reliability. Methods Utilizing PRISMA, GRADE, and MECIR protocols, we examined five databases with a modified SPIDER search. Including studies on healthy participants, published within the last 20 years, based on keywords "oxytocin," "exercise" and "measurement," 690 studies were retrieved initially (455 unique records). After excluding studies of clinically identifiable diseases, and unpublished and reproduction-focused studies, 175 studies qualified for the narrative cross-thematic and structural analysis. Results The analysis resulted in five categories showing the reciprocal impact of oxytocin and exercise: Exercise (50), Physiology (63), Environment (27), Social Context (65), and Stress (49). Exercise-induced oxytocin could promote tissue regeneration, with 32 studies showing its analgesic and anti-inflammatory effects, while 14 studies discussed memory and cognition. Furthermore, empathy-associated OXTR rs53576 polymorphism might influence team sports performance. Since dietary habits and substance abuse can impact oxytocin secretion too, combining self-report tests and repeated salivary measurements may help achieve precision. Discussion Oxytocin's effect on fear extinction and social cognition might generate strategies for mental training, and technical, and tactical development in sports. Exercise-induced oxytocin can affect the amount of stress experienced by athletes, and their response to it. However, oxytocin levels could depend on the type of sport in means of contact level, exercise intensity, and duration. The influence of oxytocin on athletes' performance and recovery could have been exploited due to its short half-life. Examining oxytocin's complex interactions with exercise paves the way for future research and application in sports science, psychology, and medical disciplines. Systematic Review Registration https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=512184, identifier CRD42024512184.
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Affiliation(s)
- Péter Szabó
- Faculty of Sciences, Institute of Sports Science and Physical Education, University of Pécs, Pécs, Hungary
- Faculty of Humanities, University of Pécs, Pécs, Hungary
- Medical School, Institute of Transdisciplinary Discoveries, University of Pécs, Pécs, Hungary
| | - Sara Bonet
- Faculty of Medicine Osijek, Josip Juraj Strossmayer University of Osijek, Osijek, Croatia
| | - Roland Hetényi
- RoLink Biotechnology Kft., Pécs, Hungary
- Hungarian National Blood Transfusion Service, Budapest, Hungary
- Szentágothai Research Centre, University of Pécs, Pécs, Hungary
- National Virology Laboratory, University of Pécs, Pécs, Hungary
| | - Dániel Hanna
- RoLink Biotechnology Kft., Pécs, Hungary
- Hungarian National Blood Transfusion Service, Budapest, Hungary
- Szentágothai Research Centre, University of Pécs, Pécs, Hungary
- National Virology Laboratory, University of Pécs, Pécs, Hungary
| | - Zsófia Kovács
- Faculty of Sciences, Institute of Sports Science and Physical Education, University of Pécs, Pécs, Hungary
| | - Gyöngyvér Prisztóka
- Faculty of Sciences, Institute of Sports Science and Physical Education, University of Pécs, Pécs, Hungary
| | - Zuzana Križalkovičová
- Faculty of Health Sciences, Institute of Physiotherapy and Sport Science, Department of Sport Science, Pécs, Hungary
| | - József Szentpéteri
- Medical School, Institute of Transdisciplinary Discoveries, University of Pécs, Pécs, Hungary
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Ferreira-Neto HC, Antunes VR, Stern JE. Purinergic P2 and glutamate NMDA receptor coupling contributes to osmotically driven excitability in hypothalamic magnocellular neurosecretory neurons. J Physiol 2021; 599:3531-3547. [PMID: 34053068 DOI: 10.1113/jp281411] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 05/28/2021] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Purinergic and glutamatergic signalling pathways play a key role in regulating the activity of hypothalamic magnocellular neurosecretory neurons (MNNs). However, the precise cellular mechanisms by which ATP and glutamate act in concert to regulate osmotically driven MNN neuronal excitability remains unknown. Here, we report that ATP acts on purinergic P2 receptors in MNNs to potentiate in a Ca2+ -dependent manner extrasynaptic NMDAR function. The P2-NMDAR coupling is engaged in response to an acute hyperosmotic stimulation, contributing to osmotically driven firing activity in MNNs. These results help us to better understand the precise mechanisms contributing to the osmotic regulation of firing activity and hormone release from MNNs. ABSTRACT The firing activity of hypothalamic magnocellular neurosecretory neurons (MNNs) located in the paraventricular nucleus (PVN) and supraoptic nucleus (SON) is coordinated by the combined, fine-tuned action of intrinsic membrane properties, synaptic and extrasynaptic signalling. Among these, purinergic and glutamatergic signalling pathways have been shown to play a key role regulating the activity of MNNs. However, the precise cellular mechanisms by which ATP and glutamate act in concert to regulate osmotically driven MNN neuronal excitability remains unknown. Whole-cell patch-clamp recordings obtained from MNNs showed that ATP (100 μM) induced an increase in firing rate, an effect that was blocked by either 4-[[4-formyl-5-hydroxy-6-methyl-3-[(phosphonooxy)methyl]2-pyridinyl]azo]1,3-benzenedisulfonic acid tetrasodium salt (PPADS) (10 μM) or kynurenic acid (1 mm). While ATP did not affect the frequency or magnitude of glutamatergic excitatory postsynaptic currents (EPSCs), it induced an inward shift in the holding current that was prevented by PPADS or kynurenic acid treatment, suggesting that ATP enhances a tonic extrasynaptic glutamatergic excitatory current. We observed that ATP-potentiated glutamatergic receptor-mediated currents were evoked by focal application of L-glu (1 mm) and NMDA (50 μM), but not AMPA (50 μM). ATP potentiation of NMDA-evoked currents was blocked by PPADS (10 μM) and by chelation of intracellular Ca2+ with BAPTA (10 mm). Finally, we report that a hyperosmotic stimulus (mannitol 1%, +55 mOsm/kgH2 O) potentiated NMDA-evoked currents and increased MNN firing activity, effects that were blocked by PPADS. Taken together, our data support a functional excitatory coupling between P2 and extrasynaptic NMDA receptors in MNNs, which is engaged in response to an acute hyperosmotic stimulus.
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Affiliation(s)
- H C Ferreira-Neto
- Neuroscience Institute, Georgia State University, Atlanta, Georgia, USA
| | - V R Antunes
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| | - J E Stern
- Neuroscience Institute, Georgia State University, Atlanta, Georgia, USA
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He Z, Young L, Ma XM, Guo Q, Wang L, Yang Y, Luo L, Yuan W, Li L, Zhang J, Hou W, Qiao H, Jia R, Tai F. Increased anxiety and decreased sociability induced by paternal deprivation involve the PVN-PrL OTergic pathway. eLife 2019; 8:44026. [PMID: 31084703 PMCID: PMC6516825 DOI: 10.7554/elife.44026] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 04/14/2019] [Indexed: 12/22/2022] Open
Abstract
Early adverse experiences often have devastating consequences. However, whether preweaning paternal deprivation (PD) affects emotional and social behaviors and their underlying neural mechanisms remain unexplored. Using monogamous mandarin voles, we found that PD increased anxiety-like behavior and attenuated social preference in adulthood. PD also decreased the number of oxytocin (OT)-positive neurons projecting from the paraventricular nucleus (PVN) and reduced the levels of the medial prefrontal cortex OT receptor protein in females and of the OT receptor and V1a receptor proteins in males. Intra-prelimbic cortical OT injections reversed the PD-induced changes in anxiety-like behavior and social preferences. Optogenetic activation of the prelimbic cortex OT terminals from PVN OT neurons reversed the PD-induced changes in emotion and social preference behaviors, whereas optogenetic inhibition was anxiogenic and impaired social preference in naive voles. These findings demonstrate that PD increases anxiety-like behavior and attenuates social preferences through the involvement of PVN OT neuron projections to the prelimbic cortex. Parental care early in life is essential for normal development of the brain in humans and some other animals. It also lays the ground work for healthy behaviors later in life. Many studies have looked at the importance of a mother’s care, but less attention has been paid to the role played by fathers. Research shows that children who grow up without a father are at risk of emotional and behavioral problems later in life. But it is not clear how missing a father’s care affects brain development. Oxytocin, a chemical produced by a part of the brain called the paraventricular nucleus, plays a key role in parental bonding. Another part of the brain called the prelimbic cortex regulates many emotions and many complex behaviors. Studying animals, like the mandarin vole, that form strong bonds with both parents is one way to learn more about how the loss of paternal care affects oxytocin or emotional and behavioral health. Now, He et al. show that mandarin voles raised without a father are more anxious and socialize less with other voles than those raised with a father. The voles deprived of paternal care also have fewer oxytocin-producing cells in the paraventricular nucleus and fewer receptors for oxytocin in the prelimbic cortex. Injecting oxytocin into the prelimbic cortex eliminated the anxious and antisocial behavior seen in the voles lacking paternal care. Using a technique called optogenetics to restore the release of oxytocin in the prelimbic cortex reduced anxious behavior and restored normal social interactions. Using the same approach to interfere with communication between the paraventricular nucleus and prelimbic cortex in voles raised with a father also triggered anxious and antisocial behavior. The experiments reveal that fathers play an important role in brain and behavioral development in mandarin voles. He et al. show that a lack of paternal care leads to deficits in oxytocin and a poor communication between the paraventricular nucleus and prelimbic cortex that contribute to emotional and social abnormalities in the voles. More studies are needed to determine father’s care has similar effects in humans. But if this relationship is confirmed, it might lead scientists to develop new strategies for treating psychiatric disorders in people deprived of paternal care.
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Affiliation(s)
- Zhixiong He
- Institute of Brain and Behavioral Sciences, College of Life Sciences, Shaanxi Normal University, Xi'an, China
| | - Larry Young
- Department of Psychiatry and Behavioral Sciences, Silvio O. Conte Center for Oxytocin and Social Cognition, Center for Translational Social Neuroscience, Yerkes National Primate Research Center, Emory University, Atlanta, United States.,Center for Social Neural Networks, University of Tsukuba, Tsukuba, Japan
| | - Xin-Ming Ma
- Institute of Brain and Behavioral Sciences, College of Life Sciences, Shaanxi Normal University, Xi'an, China.,Department of Neuroscience, University of Connecticut Health Center, Farmington, United States
| | - Qianqian Guo
- Institute of Brain and Behavioral Sciences, College of Life Sciences, Shaanxi Normal University, Xi'an, China
| | - Limin Wang
- Institute of Brain and Behavioral Sciences, College of Life Sciences, Shaanxi Normal University, Xi'an, China
| | - Yang Yang
- Institute of Brain and Behavioral Sciences, College of Life Sciences, Shaanxi Normal University, Xi'an, China
| | - Luo Luo
- Institute of Brain and Behavioral Sciences, College of Life Sciences, Shaanxi Normal University, Xi'an, China
| | - Wei Yuan
- Institute of Brain and Behavioral Sciences, College of Life Sciences, Shaanxi Normal University, Xi'an, China
| | - Laifu Li
- Institute of Brain and Behavioral Sciences, College of Life Sciences, Shaanxi Normal University, Xi'an, China
| | - Jing Zhang
- Institute of Brain and Behavioral Sciences, College of Life Sciences, Shaanxi Normal University, Xi'an, China
| | - Wenjuan Hou
- Institute of Brain and Behavioral Sciences, College of Life Sciences, Shaanxi Normal University, Xi'an, China
| | - Hui Qiao
- Institute of Brain and Behavioral Sciences, College of Life Sciences, Shaanxi Normal University, Xi'an, China
| | - Rui Jia
- Institute of Brain and Behavioral Sciences, College of Life Sciences, Shaanxi Normal University, Xi'an, China
| | - Fadao Tai
- Institute of Brain and Behavioral Sciences, College of Life Sciences, Shaanxi Normal University, Xi'an, China
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Johnson ZV, Young LJ. Oxytocin and vasopressin neural networks: Implications for social behavioral diversity and translational neuroscience. Neurosci Biobehav Rev 2017; 76:87-98. [PMID: 28434591 DOI: 10.1016/j.neubiorev.2017.01.034] [Citation(s) in RCA: 179] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Revised: 12/15/2016] [Accepted: 01/25/2017] [Indexed: 12/11/2022]
Abstract
Oxytocin- and vasopressin-related systems are present in invertebrate and vertebrate bilaterian animals, including humans, and exhibit conserved neuroanatomical and functional properties. In vertebrates, these systems innervate conserved neural networks that regulate social learning and behavior, including conspecific recognition, social attachment, and parental behavior. Individual and species-level variation in central organization of oxytocin and vasopressin systems has been linked to individual and species variation in social learning and behavior. In humans, genetic polymorphisms in the genes encoding oxytocin and vasopressin peptides and/or their respective target receptors have been associated with individual variation in social recognition, social attachment phenotypes, parental behavior, and psychiatric phenotypes such as autism. Here we describe both conserved and variable features of central oxytocin and vasopressin systems in the context of social behavioral diversity, with a particular focus on neural networks that modulate social learning, behavior, and salience of sociosensory stimuli during species-typical social contexts.
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Affiliation(s)
- Zachary V Johnson
- Silvio O. Conte Center for Oxytocin and Social Cognition, Center for Translational Social Neuroscience, Department of Psychiatry and Behavioral Sciences, Yerkes National Primate Research Center, Emory University, Atlanta, GA 30329, USA; School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA.
| | - Larry J Young
- Silvio O. Conte Center for Oxytocin and Social Cognition, Center for Translational Social Neuroscience, Department of Psychiatry and Behavioral Sciences, Yerkes National Primate Research Center, Emory University, Atlanta, GA 30329, USA.
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Busnardo C, Crestani CC, Fassini A, Resstel LBM, Corrêa FMA. NMDA and non-NMDA glutamate receptors in the paraventricular nucleus of the hypothalamus modulate different stages of hemorrhage-evoked cardiovascular responses in rats. Neuroscience 2016; 320:149-59. [PMID: 26861418 DOI: 10.1016/j.neuroscience.2016.02.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Revised: 01/18/2016] [Accepted: 02/01/2016] [Indexed: 10/22/2022]
Abstract
Here we report the involvement of N-Methyl-d-Aspartate (NMDA) and non-NMDA glutamate receptors from the paraventricular nucleus of the hypothalamus (PVN) in the mediation of cardiovascular changes observed during hemorrhage and post-bleeding periods. In addition, the present study provides further evidence of the involvement of circulating vasopressin and cardiac sympathetic activity in cardiovascular responses to hemorrhage. Systemic treatment with the V1-vasopressin receptor antagonist dTyr(CH2)5(Me)AVP (50 μg/kg, i.v.) increased the latency to the onset of hypotension during hemorrhage and slowed post-bleeding recovery of blood pressure. Systemic treatment with the β1-adrenergic receptor antagonist atenolol (1 mg/kg, i.v.) also increased the latency to the onset of hypotension during hemorrhage. Moreover, atenolol reversed the hemorrhage-induced tachycardia into bradycardia. Bilateral microinjection of the selective NMDA glutamate receptor antagonist LY235959 (2 nmol/100 nL) into the PVN blocked the hypotensive response to hemorrhage and reduced the tachycardia during the post-hemorrhage period. Systemic treatment with dTyr(CH2)5(Me)AVP inhibited the effect of LY235959 on hemorrhage-induced hypotension, without affecting the post-bleeding tachycardia. PVN treatment with the selective non-NMDA receptor antagonist NBQX (2 nmol/100 nL) reduced the recovery of blood pressure to normal levels in the post-bleeding phase and reduced hemorrhage-induced tachycardia. Combined blockade of both NMDA and non-NMDA glutamate receptors in the PVN completely abolished the hypotensive response in the hemorrhage period and reduced the tachycardiac response in the post-hemorrhage period. These results indicate that local PVN glutamate neurotransmission is involved in the neural pathway mediating cardiovascular responses to hemorrhage, via an integrated control involving autonomic nervous system activity and vasopressin release into the circulation.
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Affiliation(s)
- C Busnardo
- Department of Pharmacology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.
| | - C C Crestani
- School of Pharmaceutical Sciences, Univ. Estadual Paulista-UNESP, Araraquara, SP, Brazil
| | - A Fassini
- Department of Pharmacology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - L B M Resstel
- Department of Pharmacology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - F M A Corrêa
- Department of Pharmacology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
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VGLUTs in Peripheral Neurons and the Spinal Cord: Time for a Review. ISRN NEUROLOGY 2013; 2013:829753. [PMID: 24349795 PMCID: PMC3856137 DOI: 10.1155/2013/829753] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Accepted: 08/25/2013] [Indexed: 02/07/2023]
Abstract
Vesicular glutamate transporters (VGLUTs) are key molecules for the incorporation of glutamate in synaptic vesicles across the nervous system, and since their discovery in the early 1990s, research on these transporters has been intense and productive. This review will focus on several aspects of VGLUTs research on neurons in the periphery and the spinal cord. Firstly, it will begin with a historical account on the evolution of the morphological analysis of glutamatergic systems and the pivotal role played by the discovery of VGLUTs. Secondly, and in order to provide an appropriate framework, there will be a synthetic description of the neuroanatomy and neurochemistry of peripheral neurons and the spinal cord. This will be followed by a succinct description of the current knowledge on the expression of VGLUTs in peripheral sensory and autonomic neurons and neurons in the spinal cord. Finally, this review will address the modulation of VGLUTs expression after nerve and tissue insult, their physiological relevance in relation to sensation, pain, and neuroprotection, and their potential pharmacological usefulness.
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Malet M, Vieytes CA, Lundgren KH, Seal RP, Tomasella E, Seroogy KB, Hökfelt T, Gebhart GF, Brumovsky PR. Transcript expression of vesicular glutamate transporters in lumbar dorsal root ganglia and the spinal cord of mice - effects of peripheral axotomy or hindpaw inflammation. Neuroscience 2013; 248:95-111. [PMID: 23727452 PMCID: PMC3800240 DOI: 10.1016/j.neuroscience.2013.05.044] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Revised: 05/22/2013] [Accepted: 05/22/2013] [Indexed: 11/30/2022]
Abstract
Using specific riboprobes, we characterized the expression of vesicular glutamate transporter (VGLUT)₁-VGLUT₃ transcripts in lumbar 4-5 (L4-5) dorsal root ganglions (DRGs) and the thoracolumbar to lumbosacral spinal cord in male BALB/c mice after a 1- or 3-day hindpaw inflammation, or a 7-day sciatic nerve axotomy. Sham animals were also included. In sham and contralateral L4-5 DRGs of injured mice, VGLUT₁-, VGLUT₂- and VGLUT₃ mRNAs were expressed in ∼45%, ∼69% or ∼17% of neuron profiles (NPs), respectively. VGLUT₁ was expressed in large and medium-sized NPs, VGLUT₂ in NPs of all sizes, and VGLUT₃ in small and medium-sized NPs. In the spinal cord, VGLUT₁ was restricted to a number of NPs at thoracolumbar and lumbar segments, in what appears to be the dorsal nucleus of Clarke, and in mid laminae III-IV. In contrast, VGLUT₂ was present in numerous NPs at all analyzed spinal segments, except the lateral aspects of the ventral horns, especially at the lumbar enlargement, where it was virtually absent. VGLUT₃ was detected in a discrete number of NPs in laminae III-IV of the dorsal horn. Axotomy resulted in a moderate decrease in the number of DRG NPs expressing VGLUT₃, whereas VGLUT₁ and VGLUT₂ were unaffected. Likewise, the percentage of NPs expressing VGLUT transcripts remained unaltered after hindpaw inflammation, both in DRGs and the spinal cord. Altogether, these results confirm previous descriptions on VGLUTs expression in adult mice DRGs, with the exception of VGLUT₁, whose protein expression was detected in a lower percentage of mouse DRG NPs. A detailed account on the location of neurons expressing VGLUTs transcripts in the adult mouse spinal cord is also presented. Finally, the lack of change in the number of neurons expressing VGLUT₁ and VGLUT₂ transcripts after axotomy, as compared to data on protein expression, suggests translational rather than transcriptional regulation of VGLUTs after injury.
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Affiliation(s)
- M Malet
- Faculty of Biomedical Sciences, Austral University, Buenos Aires, Argentina; CONICET (Consejo Nacional de Investigaciones Científicas y Técnicas), Buenos Aires, Argentina
| | - C A Vieytes
- Faculty of Biomedical Sciences, Austral University, Buenos Aires, Argentina
| | - K H Lundgren
- Department of Neurology, University of Cincinnati, Cincinnati, OH, USA
| | - R P Seal
- Pittsburgh Center for Pain Research, Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, USA
| | - E Tomasella
- Faculty of Biomedical Sciences, Austral University, Buenos Aires, Argentina; CONICET (Consejo Nacional de Investigaciones Científicas y Técnicas), Buenos Aires, Argentina
| | - K B Seroogy
- Department of Neurology, University of Cincinnati, Cincinnati, OH, USA
| | - T Hökfelt
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - G F Gebhart
- Pittsburgh Center for Pain Research, Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, USA
| | - P R Brumovsky
- Faculty of Biomedical Sciences, Austral University, Buenos Aires, Argentina; CONICET (Consejo Nacional de Investigaciones Científicas y Técnicas), Buenos Aires, Argentina; Pittsburgh Center for Pain Research, Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, USA.
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Knobloch H, Charlet A, Hoffmann L, Eliava M, Khrulev S, Cetin A, Osten P, Schwarz M, Seeburg P, Stoop R, Grinevich V. Evoked Axonal Oxytocin Release in the Central Amygdala Attenuates Fear Response. Neuron 2012; 73:553-66. [DOI: 10.1016/j.neuron.2011.11.030] [Citation(s) in RCA: 748] [Impact Index Per Article: 62.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/28/2011] [Indexed: 01/26/2023]
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Some lumbar sympathetic neurons develop a glutamatergic phenotype after peripheral axotomy with a note on VGLUT₂-positive perineuronal baskets. Exp Neurol 2011; 230:258-72. [PMID: 21596036 DOI: 10.1016/j.expneurol.2011.05.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Revised: 04/27/2011] [Accepted: 05/01/2011] [Indexed: 01/01/2023]
Abstract
Glutamate is the main excitatory neurotransmitter in the nervous system, including in primary afferent neurons. However, to date a glutamatergic phenotype of autonomic neurons has not been described. Therefore, we explored the expression of vesicular glutamate transporter (VGLUT) types 1, 2 and 3 in lumbar sympathetic chain (LSC) and major pelvic ganglion (MPG) of naïve BALB/C mice, as well as after pelvic nerve axotomy (PNA), using immunohistochemistry and in situ hybridization. Colocalization with activating transcription factor-3 (ATF-3), tyrosine hydroxylase (TH), vesicular acetylcholine transporter (VAChT) and calcitonin gene-related peptide was also examined. Sham-PNA, sciatic nerve axotomy (SNA) or naïve mice were included. In naïve mice, VGLUT(2)-like immunoreactivity (LI) was only detected in fibers and varicosities in LSC and MPG; no ATF-3-immunoreactive (IR) neurons were visible. In contrast, PNA induced upregulation of VGLUT(2) protein and transcript, as well as of ATF-3-LI in subpopulations of LSC neurons. Interestingly, VGLUT(2)-IR LSC neurons coexpressed ATF-3, and often lacked the noradrenergic marker TH. SNA only increased VGLUT(2) protein and transcript in scattered LSC neurons. Neither PNA nor SNA upregulated VGLUT(2) in MPG neurons. We also found perineuronal baskets immunoreactive either for VGLUT(2) or the acetylcholinergic marker VAChT in non-PNA MPGs, usually around TH-IR neurons. VGLUT(1)-LI was restricted to some varicosities in MPGs, was absent in LSCs, and remained largely unaffected by PNA or SNA. This was confirmed by the lack of expression of VGLUT(1) or VGLUT(3) mRNAs in LSCs, even after PNA or SNA. Taken together, axotomy of visceral and non-visceral nerves results in a glutamatergic phenotype of some LSC neurons. In addition, we show previously non-described MPG perineuronal glutamatergic baskets.
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Chernigovskaya E, Atochin D, Yamova L, Huang P, Glazova M. Immunohistochemical expression of Bcl-2, p53 and caspase-9 in hypothalamus magnocellular centers of nNOS knockout mice following water deprivation. Biotech Histochem 2010; 86:333-9. [PMID: 20662604 DOI: 10.3109/10520295.2010.501706] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
We studied the interactions between apoptosis regulator proteins (Bcl-2, p53 and caspase-9) and neuronal nitric oxide in vasopressinergic magnocellular centers of the hypothalamus using neuronal nitric oxide synthase (nNOS) gene knockout mice. nNOS gene deletion resulted in accumulation of Bcl-2, p53 and caspase-9 in the paraventricular (PVN) and supraoptic (SON) nuclei in controls. Dehydration increased the levels of all three apoptosis regulator proteins studied in nuclei of wild type mice. In the hypothalamus magnocellular centers of nNOS knockout mice, however, expression of Bcl-2, p53 and caspase-9 was unchanged after dehydration. The number of magnocellular neurons did not change in the SON and PVN of nNOS deficient mice compared to wild type, and after dehydration, cell death was not observed in either nucleus of wild type or knockout mice despite activation of apoptosis regulator protein expression. Thus, we demonstrated that gene disruption of nNOS prevents activation of Bcl-2, p53 and caspase-9 expression during water deprivation, and that nNOS deficiency did not affect survival of magnocellular neurons of the hypothalamus.
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Affiliation(s)
- E Chernigovskaya
- Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, 44 Thorez pr., Saint-Petersburg 194223, Russia
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Kocsis ZS, Molnár CS, Watanabe M, Daneels G, Moechars D, Liposits Z, Hrabovszky E. Demonstration of vesicular glutamate transporter-1 in corticotroph cells in the anterior pituitary of the rat. Neurochem Int 2009; 56:479-86. [PMID: 20025917 DOI: 10.1016/j.neuint.2009.12.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2009] [Accepted: 12/11/2009] [Indexed: 11/30/2022]
Abstract
Recent immunohistochemical studies of the rat adenohypophysis identified type-2 vesicular glutamate transporter (VGLUT2), a marker for glutamatergic neuronal phenotype, in high percentages of adenohypophysial gonadotrophs and thyrotrophs. The presence and molecular identity of amino acid neurotransmitters in the remaining hormone producing cell types are unknown. In the present study we addressed the putative synthesis of another glutamatergic marker, VGLUT1 by adenohypophysial cells. Immunohistochemical studies revealed VGLUT1 immunoreactivity in a small subset of polygonal medium-sized cells in the anterior lobe. Western blot analysis revealed a single major 60 kDa protein band in the adenohypophysis. Furthermore, the expression of VGLUT1 mRNA was confirmed by reverse transcription-polymerase chain reaction followed by sequence analysis of the amplicon. In contrast with rats which only showed VGLUT1 signal in the anterior lobe of the pituitary, mice contained high levels of VGLUT1 immunoreactivity in the intermediate, in addition to the anterior lobe. No signal was present in VGLUT1-knockout mice, providing evidence for specificity. In rats, results of colocalization studies with dual-immunofluorescent labeling provided evidence for VGLUT1 immunoreactivity in 45.9% of corticotrophs and 7.7% of luteinizing hormone beta-immunopositive gonadotrophs. Cells of the other peptide hormone phenotypes were devoid of VGLUT1 signal. A few cells in the adenohypophysis expressed both VGLUT1 and VGLUT2 immunoreactivities. The presence of the glutamate markers VGLUT1 and VGLUT2 in distinct populations of peptide hormone-secreting hypophysial cells highly indicates the involvement of endogenous glutamate release in autocrine/paracrine regulatory mechanisms. The biological function of adenohypophysial glutamate will require clarification.
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Affiliation(s)
- Zsuzsa S Kocsis
- Laboratory of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest 1083, Hungary
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12
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Dal Bo G, Bérubé-Carrière N, Mendez JA, Leo D, Riad M, Descarries L, Lévesque D, Trudeau LE. Enhanced glutamatergic phenotype of mesencephalic dopamine neurons after neonatal 6-hydroxydopamine lesion. Neuroscience 2008; 156:59-70. [PMID: 18706980 DOI: 10.1016/j.neuroscience.2008.07.032] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2008] [Revised: 07/14/2008] [Accepted: 07/15/2008] [Indexed: 10/21/2022]
Abstract
There is increasing evidence that a subset of midbrain dopamine (DA) neurons uses glutamate as a co-transmitter and expresses vesicular glutamate transporter (VGLUT) 2, one of the three vesicular glutamate transporters. In the present study, double in situ hybridization was used to examine tyrosine hydroxylase (TH) and VGLUT2 mRNA expression during the embryonic development of these neurons, and postnatally, in normal rats and rats injected with 6-hydroxydopamine (6-OHDA) at P4 to destroy partially DA neurons. At embryonic days 15 and 16, there was a regional overlap in the labeling of TH and VGLUT2 mRNA in the ventral mesencephalon, which was no longer found at late embryonic stages (E18-E21) and postnatally. In normal pups from P5 to P15, only 1-2% of neurons containing TH mRNA in the ventral tegmental area (VTA) and substantia nigra, pars compacta, also displayed VGLUT2 mRNA. In contrast, after the cerebroventricular administration of 6-OHDA at P4, 26% of surviving DA neurons in the VTA of P15 rats expressed VGLUT2. To search for a colocalization of TH and VGLUT2 protein in axon terminals of these neurons, the nucleus accumbens of normal and 6-OHDA-lesioned P15 rats was examined by electron microscopy after dual immunocytochemical labeling. In normal rats, VGLUT2 protein was found in 28% of TH positive axon terminals in the core of nucleus accumbens. In 6-OHDA-lesioned rats, the total number of TH positive terminals was considerably reduced, and yet the proportion also displaying VGLUT2 immunoreactivity was modestly but significantly increased (37%). These results lead to the suggestion that the glutamatergic phenotype of a VTA DA neurons is highly plastic, repressed toward the end of normal embryonic development, and derepressed postnatally following injury. They also support the hypothesis of co-release of glutamate and DA by mesencephalic neurons in vivo, at least in the developing brain.
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Affiliation(s)
- G Dal Bo
- Department of Pharmacology, Faculty of Medicine, Université de Montréal, C.P. 6128, Succursale Centre-Ville, Montréal, QC, Canada H3C 3J7
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13
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Abstract
L-glutamate, the main excitatory neurotransmitter, influences virtually all neurones of the neuroendocrine hypothalamus via synaptic mechanisms. Vesicular glutamate transporters (VGLUT1-3), which selectively accumulate L-glutamate into synaptic vesicles, provide markers with which to visualise glutamatergic neurones in histological preparations; excitatory neurones in the endocrine hypothalamus synthesise the VGLUT2 isoform. Results of recent dual-label in situ hybridisation studies indicate that glutamatergic neurones in the preoptic area and the hypothalamic paraventricular, supraoptic and periventricular nuclei include parvocellular and magnocellular neurosecretory neurones which secrete peptide neurohormones into the bloodstream to regulate endocrine functions. Neurosecretory terminals of GnRH, TRH, CRF-, somatostatin-, oxytocin- and vasopressin-secreting neurones contain VGLUT2 immunoreactivity, suggesting the co-release of glutamate with hypophysiotrophic peptides. The presence of VGLUT2 also indicates glutamate secretion from non-neuronal endocrine cells, including gonadotrophs and thyrotrophs of the anterior pituitary. Results of in vitro studies show that ionotropic glutamate receptor analogues can elicit hormone secretion at neuroendocrine/endocrine release sites. Structural constituents of the median eminence, adenohypophysis and neurohypophysis contain elements of glutamatergic transmission, including glutamate receptors and enzymes of the glutamate/glutamine cycle. The synthesis of VGLUT2 exhibits robust up-regulation in response to certain endocrine challenges, indicating that altered glutamatergic signalling may represent an important adaptive mechanism. This review article discusses the newly emerged non-synaptic role of glutamate in neuroendocrine and endocrine communication.
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Affiliation(s)
- E Hrabovszky
- Laboratory of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
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Kashiwagi H, Yamazaki K, Takekuma Y, Ganapathy V, Sugawara M. Regulatory mechanisms of SNAT2, an amino acid transporter, in L6 rat skeletal muscle cells by insulin, osmotic shock and amino acid deprivation. Amino Acids 2008; 36:219-30. [PMID: 18330498 DOI: 10.1007/s00726-008-0050-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2007] [Accepted: 02/15/2008] [Indexed: 10/22/2022]
Abstract
Several studies have demonstrated that the activity of system A is upregulated by insulin, osmotic shock and amino acid deprivation. However, the mechanisms are not clear. We carried out studies using L6 rat skeletal muscle cells to clarify the mechanisms of upregulation of system A activity by insulin, osmotic shock and amino acid deprivation. The upregulation was found to be due to an increase in Vmax, not Km. Chloroquine and wortmannin inhibited the upregulation induced by insulin stimulation and amino acid deprivation but not that induced by osmotic shock. On the other hand, cycloheximide and actinomycin D inhibited the upregulation by each stimulation. Moreover, PD98059 and SP600125 inhibited only amino acid deprivation-induced upregulation and SB202190 inhibited only insulin-induced upregulation. Our findings indicate that the mechanisms of upregulation of system A activity by insulin, osmotic shock and amino acid deprivation are different in L6 cells. Western blot and RT-PCR analysis showed an increase in system A at the protein and mRNA levels with each stimulation.
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Affiliation(s)
- Hitoshi Kashiwagi
- Department of Pharmacy, Hokkaido University Hospital, Sapporo, Hokkaido, Japan
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15
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Konno J, Yoshida S, Ina A, Ohmomo H, Shutoh F, Nogami H, Hisano S. Upregulated expression of neuropeptide Y in hypothalamic–pituitary system of rats by chronic dexamethasone administration. Neurosci Res 2008; 60:259-65. [DOI: 10.1016/j.neures.2007.11.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2007] [Revised: 10/30/2007] [Accepted: 11/14/2007] [Indexed: 10/22/2022]
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Llewellyn-Smith IJ, Martin CL, Fenwick NM, Dicarlo SE, Lujan HL, Schreihofer AM. VGLUT1 and VGLUT2 innervation in autonomic regions of intact and transected rat spinal cord. J Comp Neurol 2007; 503:741-67. [PMID: 17570127 DOI: 10.1002/cne.21414] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Fast excitatory neurotransmission to sympathetic and parasympathetic preganglionic neurons (SPN and PPN) is glutamatergic. To characterize this innervation in spinal autonomic regions, we localized immunoreactivity for vesicular glutamate transporters (VGLUTs) 1 and 2 in intact cords and after upper thoracic complete transections. Preganglionic neurons were retrogradely labeled by intraperitoneal Fluoro-Gold or with cholera toxin B (CTB) from superior cervical, celiac, or major pelvic ganglia or adrenal medulla. Glutamatergic somata were localized with in situ hybridization for VGLUT mRNA. In intact cords, all autonomic areas contained abundant VGLUT2-immunoreactive axons and synapses. CTB-immunoreactive SPN and PPN received many close appositions from VGLUT2-immunoreactive axons. VGLUT2-immunoreactive synapses occurred on Fluoro-Gold-labeled SPN. Somata with VGLUT2 mRNA occurred throughout the spinal gray matter. VGLUT2 immunoreactivity was not noticeably affected caudal to a transection. In contrast, in intact cords, VGLUT1-immunoreactive axons were sparse in the intermediolateral cell column (IML) and lumbosacral parasympathetic nucleus but moderately dense above the central canal. VGLUT1-immunoreactive close appositions were rare on SPN in the IML and the central autonomic area and on PPN. Transection reduced the density of VGLUT1-immunoreactive axons in sympathetic subnuclei but increased their density in the parasympathetic nucleus. Neuronal cell bodies with VGLUT1 mRNA occurred only in Clarke's column. These data indicate that SPN and PPN are densely innervated by VGLUT2-immunoreactive axons, some of which arise from spinal neurons. In contrast, the VGLUT1-immunoreactive innervation of spinal preganglionic neurons is sparse, and some may arise from supraspinal sources. Increased VGLUT1 immunoreactivity after transection may correlate with increased glutamatergic transmission to PPN.
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Affiliation(s)
- Ida J Llewellyn-Smith
- Cardiovascular Medicine and Centre for Neuroscience, Flinders University, Bedford Park, South Australia 5042, Australia.
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Hrabovszky E, Deli L, Turi GF, Kalló I, Liposits Z. Glutamatergic innervation of the hypothalamic median eminence and posterior pituitary of the rat. Neuroscience 2007; 144:1383-92. [PMID: 17175111 DOI: 10.1016/j.neuroscience.2006.10.053] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2006] [Revised: 10/26/2006] [Accepted: 10/28/2006] [Indexed: 11/18/2022]
Abstract
Recent studies have localized the glutamatergic cell marker type-2 vesicular glutamate transporter (VGLUT2) to distinct peptidergic neurosecretory systems that regulate hypophysial functions in rats. The present studies were aimed to map the neuronal sources of VGLUT2 in the median eminence and the posterior pituitary, the main terminal fields of hypothalamic neurosecretory neurons. Neurons innervating these regions were identified by the uptake of the retrograde tract-tracer Fluoro-Gold (FG) from the systemic circulation, whereas glutamatergic perikarya of the hypothalamus were visualized via the radioisotopic in situ hybridization detection of VGLUT2 mRNA. The results of dual-labeling studies established that the majority of neurons accumulating FG and also expressing VGLUT2 mRNA were located within the paraventricular, periventricular and supraoptic nuclei and around the organum vasculosum of the lamina terminalis and the preoptic area. In contrast, only few FG-accumulating cells exhibited VGLUT2 mRNA signal in the arcuate nucleus. Dual-label immunofluorescent studies of the median eminence and posterior pituitary to determine the subcellular location of VGLUT2, revealed the association of VGLUT2 immunoreactivity with SV2 protein, a marker for small clear vesicles in neurosecretory endings. Electron microscopic studies using pre-embedding colloidal gold labeling confirmed the localization of VGLUT2 in small clear synaptic vesicles. These data suggest that neurosecretory neurons located mainly within the paraventricular, anterior periventricular and supraoptic nuclei and around the organum vasculosum of the lamina terminalis and the preoptic area secrete glutamate into the fenestrated vessels of the median eminence and posterior pituitary. The functional aspects of the putative neuropeptide/glutamate co-release from neuroendocrine terminals remain to be elucidated.
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Affiliation(s)
- E Hrabovszky
- Laboratory of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, P.O. Box 67, 1450 Budapest, Hungary
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Yamaguchi K, Yamada T. Involvement of anteroventral third ventricular AMPA/kainate receptors in both hyperosmotic and hypovolemic AVP secretion in conscious rats. Brain Res Bull 2006; 71:183-92. [PMID: 17113945 DOI: 10.1016/j.brainresbull.2006.09.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2006] [Revised: 09/07/2006] [Accepted: 09/07/2006] [Indexed: 02/05/2023]
Abstract
The area of the brain called the anteroventral third ventricular region (AV3V) includes three different subtypes of glutamate receptor, as well as neural circuits controlling fluid balance and cardiovascular and neuroendocrine functions. Although our previous data indicate the ability of AV3V N-methyl-d-aspartate (NMDA) and metabotropic receptors to provoke vasopressin (AVP)-releasing, pressor and hyperglycemic responses, the roles of non-NMDA receptors selective for alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid and kainate have not been elucidated to date. To address this question, the effects of intracerebral infusion with FWD or NBQX (specific agonist and antagonist for non-NMDA receptors, respectively) on plasma AVP, glucose, osmolality, electrolytes and cardiovascular parameters were examined in conscious rats in the absence or presence of an osmotic or volemic stimulus. When applied topically to AV3V structures such as the median preoptic nucleus, FWD augmented plasma AVP, osmolality, glucose and arterial pressure in a dose-associated fashion. All responses of the variables were abolished by pre-administering NBQX, which exerted no conspicuous effect on any variable except arterial pressure. It was revealed that NBQX administration in AV3V structures such as the median preoptic nucleus and the periventricular nucleus inhibited the rise of plasma AVP in response to intravenous infusion with hypertonic saline or removal of systemic blood through the femoral artery. Elevation of plasma osmolality and sodium evoked by osmotic load, and elevation of plasma osmolality, glucose and angiotensin II and decrease of arterial pressure caused by bleeding, were not significantly affected by NBQX treatment. These results suggest that AV3V non-NMDA receptors, as well as NMDA receptors, may elicit AVP-releasing, pressor and hyperglycemic actions when stimulated in the basal state, and may facilitate AVP secretion under both hyperosmotic and hypovolemic conditions, without contributing to cardiovascular, blood glucose or other responses.
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Affiliation(s)
- Ken'ichi Yamaguchi
- Department of Homeostatic Regulation and Development, Niigata University Graduate School of Medical and Dental Sciences, Asahimachi-Dori 1-757, Niigata City, Niigata Prefecture 951-8510, Japan.
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Hrabovszky E, Kalló I, Turi GF, May K, Wittmann G, Fekete C, Liposits Z. Expression of vesicular glutamate transporter-2 in gonadotrope and thyrotrope cells of the rat pituitary. Regulation by estrogen and thyroid hormone status. Endocrinology 2006; 147:3818-25. [PMID: 16675529 DOI: 10.1210/en.2005-1229] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Immunocytochemical studies of the rat adenohypophysis identified a cell population that exhibits immunoreactivity for type-2 vesicular glutamate transporter (VGLUT2), a marker for glutamatergic neuronal phenotype. The in situ hybridization detection of VGLUT2 mRNA expression in adenohypophysial cells verified that VGLUT2 immunoreactivity is due to local synthesis of authentic VGLUT2. Dual-immunofluorescent studies of the hypophyses from male rats showed the presence of VGLUT2 in high percentages of LH (93.3 +/- 1.3%)-, FSH (44.7 +/- 3.9%)-, and TSH (70.0 +/- 5.6%)-immunoreactive cells and its much lower incidence in cells of the prolactin, GH, and ACTH phenotypes. Quantitative in situ hybridization studies have established that the administration of a single dose of 17-beta-estradiol (20 microg/kg; sc) to ovariectomized rats significantly elevated VGLUT2 mRNA in the adenohypophysis 16 h postinjection. Thyroid hormone dependence of VGLUT2 expression was addressed by the comparison of hybridization signals in animal models of hypo- and hyperthyroidism to those in euthyroid controls. Although hyperthyroidism had no effect on VGLUT2 mRNA, hypothyroidism increased adenohypophysial VGLUT2 mRNA levels. This coincided with a decreased ratio of VGLUT2-immunoreactive TSH cells, regarded as a sign of enhanced secretion. The presence of the glutamate marker VGLUT2 in gonadotrope and thyrotrope cells, and its up-regulation by estrogen or hypothyroidism, address the possibility that endocrine cells of the adenohypophysis may cosecrete glutamate with peptide hormones in an estrogen- and thyroid status-regulated manner. The exact roles of endogenous glutamate observed primarily in gonadotropes and thyrotropes, including its putative involvement in autocrine/paracrine regulatory mechanisms, will require clarification.
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Affiliation(s)
- Erik Hrabovszky
- Laboratory of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Szigony u. 43, Budapest, 1083 Hungary.
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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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Hrabovszky E, Csapó AK, Kalló I, Wilheim T, Túri GF, Liposits Z. Localization and osmotic regulation of vesicular glutamate transporter-2 in magnocellular neurons of the rat hypothalamus. Neurochem Int 2006; 48:753-61. [PMID: 16481069 DOI: 10.1016/j.neuint.2005.12.013] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2005] [Accepted: 12/21/2005] [Indexed: 12/01/2022]
Abstract
In this report we present immunocytochemical and in situ hybridization evidence that magnocellular vasopressin and oxytocin neurons in the hypothalamic supraoptic and paraventricular nuclei express type-2 vesicular glutamate transporter, a marker for their glutamatergic neuronal phenotype. To address the issue of whether an increase in magnocellular neuron activity coincides with the altered synthesis of the endogenous glutamate marker, we have introduced a new dual-label in situ hybridization method which combines fluorescent and autoradiographic signal detection components for vasopressin and vesicular glutamate transporter-2 mRNAs, respectively. Application of this technique provided evidence that 2% sodium chloride in the drinking water for 7 days produced a robust and significant increase of vesicular glutamate transporter-2 mRNA in vasopressin neurons of the supraoptic nucleus. The immunocytochemical labeling of pituitary sections, followed by the densitometric analysis of vesicular glutamate transporter-2 immunoreactivity in the posterior pituitary, revealed a concomitant increase in vesicular glutamate transporter-2 protein levels at the major termination site of the magnocellular axons. These data demonstrate that magnocellular oxytocin as well as vasopressin cells contain the glutamatergic marker vesicular glutamate transporter-2, similarly to most of the parvicellular neurosecretory neurons examined so far. The robust increase in vesicular glutamate transporter-2 mRNA and immunoreactivity after salt loading suggests that the cellular levels of vesicular glutamate transporter-2 in vasopressin neurons are regulated by alterations in water-electrolyte balance. In addition to the known synaptic actions of excitatory amino acids in magnocellular nuclei, the new observations suggest novel mechanisms whereby glutamate of endogenous sources can regulate magnocellular neuronal functions.
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Affiliation(s)
- E Hrabovszky
- Laboratory of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Szigony u. 43, Budapest 1083, Hungary.
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