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Xiao F, Hu A, Meng B, Zhang Y, Han W, Su J. PVH-Peri5 Pathway for Stress-Coping Oromotor and Anxious Behaviors in Mice. J Dent Res 2023; 102:227-237. [PMID: 36303441 DOI: 10.1177/00220345221130305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Stressful stimuli can activate the hypothalamic-pituitary-adrenal (HPA) axis. Clinically, it has been widely reported that stressful events are often accompanied by teeth clenching and bruxism, while mastication (chewing) can promote coping with stress. Trigeminal motoneurons in the trigeminal motor nucleus supplying the chewing muscles receive direct inputs from interneurons within the peritrigeminal premotor area (Peri5). Previous studies found that the paraventricular hypothalamic nucleus (PVH) participates in trigeminal activities during stressful events. However, the neural pathway by which the stress-induced oral movements alleviate stress is largely unknown. We hypothesized that paraventricular-trigeminal circuits might be associated with the stress-induced chewing movements and anxiety levels. First, we observed the stress-coping effect of wood gnawing on stress-induced anxiety, with less anxiety-like behaviors seen in the open field test and elevated plus maze, as well as decreased corticosterone and blood glucose levels, in response to stress in mice. We then found that excitotoxic lesions of PVH reduced the effect of gnawing on stress, reflected in more anxiety-like behaviors; this emphasizes the importance of the PVH in stress responses. Anterograde, retrograde, transsynaptic, and nontranssynaptic tracing through central and peripheral injections confirmed monosynaptic projections from PVH to Peri5. We discovered that PVH receives proprioceptive sensory inputs from the jaw muscle and periodontal ligaments, as well as provides motor outputs via the mesencephalic trigeminal nucleus (Me5) and Peri5. Next, pathway-specific functional manipulation by chemogenetic inhibition was conducted to further explore the role of PVH-Peri5 monosynaptic projections. Remarkably, PVH-Peri5 inhibition decreased gnawing but did not necessarily reduce stress-induced anxiety. Moreover, neuropeptide B (NPB) was expressed in Peri5-projecting PVH neurons, indicating that NPB signaling may mediate the effects of PVH-Peri5. In conclusion, our data revealed a PVH-Peri5 circuit that plays a role in the stress response via its associations with oromotor movements and relative anxiety-like behaviors.
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Affiliation(s)
- F Xiao
- Department of Prosthodontics, Stomatological Hospital and Dental School of Tongji University, Shanghai Engineering Research Center of Tooth Restoration and Regeneration, Shanghai, China
| | - A Hu
- Department of Prosthodontics, Stomatological Hospital and Dental School of Tongji University, Shanghai Engineering Research Center of Tooth Restoration and Regeneration, Shanghai, China
| | - B Meng
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA, USA.,Department of Neurology, Emory University School of Medicine, Atlanta, GA, USA
| | - Y Zhang
- Department of Prosthodontics, Stomatological Hospital and Dental School of Tongji University, Shanghai Engineering Research Center of Tooth Restoration and Regeneration, Shanghai, China
| | - W Han
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York City, NY, USA
| | - J Su
- Department of Prosthodontics, Stomatological Hospital and Dental School of Tongji University, Shanghai Engineering Research Center of Tooth Restoration and Regeneration, Shanghai, China
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Ji YY, Liu X, Li X, Xiao YF, Ma T, Wang J, Feng Y, Shi J, Wang MQ, Li JL, Lai JH. Activation of the Vpdm VGLUT1-VPM pathway contributes to anxiety-like behaviors induced by malocclusion. Front Cell Neurosci 2022; 16:995345. [PMID: 36605612 PMCID: PMC9807610 DOI: 10.3389/fncel.2022.995345] [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: 07/15/2022] [Accepted: 11/29/2022] [Indexed: 12/24/2022] Open
Abstract
Occlusal disharmony has a negative impact on emotion. The mesencephalic trigeminal nucleus (Vme) neurons are the primary afferent nuclei that convey proprioceptive information from proprioceptors and low-threshold mechanoreceptors in the periodontal ligament and jaw muscles in the cranio-oro-facial regions. The dorsomedial part of the principal sensory trigeminal nucleus (Vpdm) and the ventral posteromedial nucleus (VPM) of thalamus have been proven to be crucial relay stations in ascending pathway of proprioception. The VPM sends numerous projections to primary somatosensory areas (SI), which modulate emotion processing. The present study aimed to demonstrate the ascending trigeminal-thalamic-cortex pathway which would mediate malocclusion-induced negative emotion. Unilateral anterior crossbite (UAC) model created by disturbing the dental occlusion was applied. Tract-tracing techniques were used to identify the existence of Vme-Vpdm-VPM pathway and Vpdm-VPM-SI pathway. Chemogenetic and optogenetic methods were taken to modulate the activation of VpdmVGLUT1 neurons and the Vpdm-VPM pathway. Morphological evidence indicated the involvement of the Vme-Vpdm-VPM pathway, Vpdm-VPM-SI pathway and VpdmVGLUT1-VPM pathway in orofacial proprioception in wild-type mice and vesicular glutamate transporter 1 (VGLUT1): tdTomato mice, respectively. Furthermore, chemogenetic inhibition of VpdmVGLUT1 neurons and the Vpdm-VPM pathway alleviated anxiety-like behaviors in a unilateral anterior crossbite (UAC) model, whereas chemogenetic activation induced anxiety-like behaviors in controls and did not aggravate these behaviors in UAC mice. Finally, optogenetic inhibition of the VpdmVGLUT1-VPM pathway in VGLUT1-IRES-Cre mice reversed UAC-induced anxiety comorbidity. In conclusion, these results suggest that the VpdmVGLUT1-VPM neural pathway participates in the modulation of malocclusion-induced anxiety comorbidity. These findings provide new insights into the links between occlusion and emotion and deepen our understanding of the impact of occlusal disharmony on brain dysfunction.
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Affiliation(s)
- Yuan-Yuan Ji
- College of Forensic Science, Xi’an Jiaotong University, Xi’an, China,Department of Anatomy, School of Medicine, Northwest University, Xi’an, China,Department of Anatomy, K. K. Leung Brain Research Centre, Fourth Military Medical University, Xi’an, China
| | - Xin Liu
- State Key Laboratory of Military Stomatology, Department of Oral Anatomy and Physiology, National Clinical Research Center for Oral Diseases, Shaanxi International Joint Research Center for Oral Diseases, School of Stomatology, Fourth Military Medical University, Xi’an, China,Department of Stomatology, The 960th Hospital of People’s Liberation Army, Jinan, China
| | - Xin Li
- Department of Stomatology, The 960th Hospital of People’s Liberation Army, Jinan, China
| | - Yi-Fan Xiao
- Department of Anatomy, School of Medicine, Northwest University, Xi’an, China
| | - Teng Ma
- Functional and Molecular Imaging Key Lab of Shaanxi Province, Department of Radiology, Tangdu Hospital, Fourth Military Medical University, Xi’an, China
| | - Jian Wang
- Department of Neurosurgery, Tangdu Hospital, Fourth Military Medical University, Xi’an, China
| | - Yue Feng
- College of Forensic Science, Xi’an Jiaotong University, Xi’an, China
| | - Juan Shi
- Department of Anatomy, K. K. Leung Brain Research Centre, Fourth Military Medical University, Xi’an, China
| | - Mei-Qing Wang
- State Key Laboratory of Military Stomatology, Department of Oral Anatomy and Physiology, National Clinical Research Center for Oral Diseases, Shaanxi International Joint Research Center for Oral Diseases, School of Stomatology, Fourth Military Medical University, Xi’an, China,*Correspondence: Mei-Qing Wang,
| | - Jin-Lian Li
- Department of Anatomy, School of Medicine, Northwest University, Xi’an, China,Department of Anatomy, K. K. Leung Brain Research Centre, Fourth Military Medical University, Xi’an, China,Jin-Lian Li,
| | - Jiang-Hua Lai
- College of Forensic Science, Xi’an Jiaotong University, Xi’an, China,Jiang-Hua Lai,
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Zhao YJ, Liu Y, Wang J, Li Q, Zhang ZM, Tu T, Lei R, Zhang M, Chen YJ. Activation of the Mesencephalic Trigeminal Nucleus Contributes to Masseter Hyperactivity Induced by Chronic Restraint Stress. Front Cell Neurosci 2022; 16:841133. [PMID: 35480958 PMCID: PMC9035558 DOI: 10.3389/fncel.2022.841133] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 03/11/2022] [Indexed: 12/12/2022] Open
Abstract
Psychological stress is commonly accepted to be closely associated with masticatory muscle disorder, which is the main symptom of temporomandibular disorder (TMD). Previous studies have confirmed that exposure to stress may cause masticatory muscle hyperactivity. However, the central mechanism underlying this process remains unclear. The mesencephalic trigeminal nucleus (Vme), which resides in the brainstem, is the primary afferent center for masticatory proprioception and plays a key role in oral–motor movements by projecting to the trigeminal motor nucleus (Vmo). Therefore, the present study was designed to examine the role of Vme neurons in masseter overactivity induced by chronic stress. We found that subjecting mice to restraint stress (6 h/day) for 14 days caused significant anxiety-like behavior, obvious masseter overactivity, and markedly enhanced electrophysiological excitability of Vme neurons. By using anterograde tract tracing combined with immunofluorescence staining methods, we observed vesicular glutamate transporter 1 (VGLUT1)-positive glutamatergic projections from the Vme to the Vmo. Moreover, chronic restraint stress (CRS) elevated the expression of VGLUT1 and choline acetyltransferase (ChAT) in Vmo. Furthermore, administration of VGLUT1-targeted short hairpin RNA (shRNA) into the bilateral Vme significantly suppressed the enhanced overexcitability of Vme neurons, downregulated the overexpression of VGLUT1 and ChAT in the Vmo, and attenuated the elevated overactivity of the masseter caused by CRS. Taken together, we showed that CRS can excite neurons in the Vme, enhancing glutamatergic excitatory projections from the Vme to the Vmo and resulting in masseter muscle overactivity. These findings provide us with a novel central mechanism underlying the correlation between psychological factors and TMD.
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Affiliation(s)
- Ya-Juan Zhao
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi International Joint Research Center for Oral Diseases, Department of General Dentistry and Emergency, School of Stomatology, Fourth Military Medical University, Xi’an, China
| | - Yang Liu
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi International Joint Research Center for Oral Diseases, Department of General Dentistry and Emergency, School of Stomatology, Fourth Military Medical University, Xi’an, China
| | - Jian Wang
- Department of Cardiothoracic Surgery, General Hospital of Western Theater Command, Chengdu, China
| | - Qiang Li
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi International Joint Research Center for Oral Diseases, Department of General Dentistry and Emergency, School of Stomatology, Fourth Military Medical University, Xi’an, China
| | - Zhou-Ming Zhang
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi International Joint Research Center for Oral Diseases, Department of General Dentistry and Emergency, School of Stomatology, Fourth Military Medical University, Xi’an, China
| | - Teng Tu
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi International Joint Research Center for Oral Diseases, Department of General Dentistry and Emergency, School of Stomatology, Fourth Military Medical University, Xi’an, China
| | - Rong Lei
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi International Joint Research Center for Oral Diseases, Department of General Dentistry and Emergency, School of Stomatology, Fourth Military Medical University, Xi’an, China
| | - Min Zhang
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi International Joint Research Center for Oral Diseases, Department of General Dentistry and Emergency, School of Stomatology, Fourth Military Medical University, Xi’an, China
- Min Zhang,
| | - Yong-Jin Chen
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi International Joint Research Center for Oral Diseases, Department of General Dentistry and Emergency, School of Stomatology, Fourth Military Medical University, Xi’an, China
- *Correspondence: Yong-Jin Chen,
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Shi M, Liu X, Zhang C, Zhang H, Liu Q, Wang D, Liu X, Li J, Wang M. Effect of dental malocclusion on cerebellar neuron activation via the dorsomedial part of the principal sensory trigeminal nucleus. Eur J Oral Sci 2021; 129:e12788. [PMID: 33945647 PMCID: PMC8453929 DOI: 10.1111/eos.12788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 03/10/2021] [Accepted: 03/12/2021] [Indexed: 11/30/2022]
Abstract
Occlusion has been proposed to play a role for body posture and balance, both of which are mediated mainly by the cerebellum. The dorsomedial part of the principal sensory trigeminal nucleus (Vpdm) has direct projection to the cerebellum. The experimental unilateral anterior crossbite (UAC) has an impact on the motor nuclei in the brain stem via trigeminal mesencephalic nucleus (Vme). The current aim was to explore whether UAC has an impact on Vpdm‐cerebellum circuit. The inferior alveolar nerve was injected into cholera toxin B subunit (CTb), the cerebellum was injected into fluoro‐gold (FG), and the Vpdm was injected into biotinylated dextran amine (BDA) to identify the activation of Vpdm‐cerebellum circuit by UAC. Data indicated that there were more neuronal nuclei (NeuN)/CTb/FG triple‐labelled neurons and NeuN/CTb/vesicular glutamate transporter 1(VGLUT1) triple‐labelled neurons in the Vpdm, and more NeuN/BDA/ VGLUT1 triple‐labelled neurons in the cerebellum of rats with UAC than in control rats. The VGLUT1 expression in the Vpdm and cerebellum in the UAC group was higher than that in control rats. These findings indicate an excitatory impact of UAC on the Vpdm‐cerebellum pathway and support the role of occlusion for body posture and balance.
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Affiliation(s)
- Minghong Shi
- School of Stomatology, The Third Affiliated Hospital of Xinxiang Medical University, Xinxiang, China.,Department of Oral Anatomy and Physiology, School of Stomatology, The Fourth Military Medical University, Xi'an, China
| | - Xin Liu
- Department of Oral Anatomy and Physiology, School of Stomatology, The Fourth Military Medical University, Xi'an, China.,Department of Stomatology, The 960th Hospital of People's Liberation Army, Jinan, China
| | - Chunkui Zhang
- Department of Anatomy, Histology and Embryology and K.K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China
| | - Hongyun Zhang
- Department of Oral Anatomy and Physiology, School of Stomatology, The Fourth Military Medical University, Xi'an, China
| | - Qian Liu
- Department of Oral Anatomy and Physiology, School of Stomatology, The Fourth Military Medical University, Xi'an, China
| | - Dongmei Wang
- School of Stomatology, The Third Affiliated Hospital of Xinxiang Medical University, Xinxiang, China
| | - Xiaodong Liu
- Department of Oral Anatomy and Physiology, School of Stomatology, The Fourth Military Medical University, Xi'an, China
| | - Jinlian Li
- Department of Anatomy, Histology and Embryology and K.K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China
| | - Meiqing Wang
- School of Stomatology, The Third Affiliated Hospital of Xinxiang Medical University, Xinxiang, China.,Department of Oral Anatomy and Physiology, School of Stomatology, The Fourth Military Medical University, Xi'an, China
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Paik SK, Yoshida A, Bae YC. Development of γ-aminobutyric acid-, glycine-, and glutamate-immunopositive boutons on the rat genioglossal motoneurons. Brain Struct Funct 2021; 226:889-900. [PMID: 33475854 DOI: 10.1007/s00429-021-02216-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 01/08/2021] [Indexed: 12/13/2022]
Abstract
Detailed information about the development of excitatory and inhibitory synapses on the genioglossal (GG) motoneuron may help to understand the mechanism of fine control of GG motoneuron firing and the coordinated tongue movement during postnatal development. For this, we investigated the development of γ-aminobutyric acid (GABA)-immunopositive (GABA +), glycine + (Gly +), and glutamate + (Glut +) axon terminals (boutons) on the somata of rat GG motoneurons at a postnatal day 2 (P2), P6 and P18 by retrograde labeling of GG motoneurons with horseradish peroxidase, electron microscopic postembedding immunogold staining with GABA, Gly, and Glut antisera, and quantitative analysis. The number of boutons per GG motoneuron somata and the mean length of bouton apposition, measures of bouton size and synaptic covering percentage, were significantly increased from P2/P6 to P18. The number and fraction of GABA + only boutons of all boutons decreased significantly, whereas those of Gly + only boutons increased significantly from P2/P6 to P18, suggesting developmental switch from GABAergic to glycinergic synaptic transmission. The fraction of mixed GABA +/Gly + boutons of all boutons was the highest among inhibitory bouton types throughout the postnatal development. The fractions of excitatory and inhibitory boutons of all boutons remained unchanged during postnatal development. These findings reveal a distinct developmental pattern of inhibitory synapses on the GG motoneurons different from that on spinal or trigeminal motoneurons, which may have an important role in the regulation of the precise and coordinated movements of the tongue during the maturation of the oral motor system.
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Affiliation(s)
- Sang Kyoo Paik
- Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, 188-1, 2-Ga, Samdeok-Dong, Jung-Gu, Daegu, 700-412, Korea
| | - Atsushi Yoshida
- Department of Oral Anatomy and Neurobiology, Graduate School of Dentistry, Osaka University, Osaka, 565-0871, Japan
| | - Yong Chul Bae
- Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, 188-1, 2-Ga, Samdeok-Dong, Jung-Gu, Daegu, 700-412, Korea.
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Liu X, Shi M, Ren H, Xie M, Zhang C, Wang D, Liu X, Li J, Wang M. Excitatory Impact of Dental Occlusion on Dorsal Motor Nucleus of Vagus. Front Neural Circuits 2021; 15:638000. [PMID: 33776655 PMCID: PMC7994330 DOI: 10.3389/fncir.2021.638000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 02/19/2021] [Indexed: 11/13/2022] Open
Abstract
Neurons in the trigeminal mesencephalic nucleus (Vme) have axons that branch peripherally to innervate the orofacial region and project centrally to several motor nuclei in brainstem. The dorsal motor nucleus of vagus nerve (DMV) resides in the brainstem and takes a role in visceral motor function such as pancreatic exocrine secretion. The present study aimed to demonstrate the presence of Vme-DMV circuit, activation of which would elicit a trigeminal neuroendocrine response. A masticatory dysfunctional animal model termed unilateral anterior crossbite (UAC) model created by disturbing the dental occlusion was used. Cholera toxin B subunit (CTb) was injected into the inferior alveolar nerve of rats to help identify the central axon terminals of Vme neurons around the choline acetyltransferase (ChAT) positive motor neurons in the DMV. The level of vesicular glutamate transporter 1 (VGLUT1) expressed in DMV, the level of acetylcholinesterase (AChE) expressed in pancreas, the level of glucagon and insulin expression in islets and serum, and the blood glucose level were detected and compared between UAC and the age matched sham-operation control mice. Data indicated that compared with the controls, there were more CTb/VGLUT1 double labeled axon endings around the ChAT positive neurons in the DMV of UAC groups. Mice in UAC group expressed a higher VGLUT1 protein level in DMV, AChE protein level in pancreas, glucagon and insulin level in islet and serum, and higher postprandial blood glucose level, but lower fasting blood glucose level. All these were reversed at 15-weeks when UAC cessation was performed from 11-weeks (all, P < 0.05). Our findings demonstrated Vme-DMV circuit via which the aberrant occlusion elicited a trigeminal neuroendocrine response such as alteration in the postprandial blood glucose level. Dental occlusion is proposed as a potential therapeutic target for reversing the increased postprandial glucose level.
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Affiliation(s)
- Xin Liu
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi International Joint Research Center for Oral Diseases, Department of Oral Anatomy and Physiology, School of Stomatology, The Fourth Military Medical University, Xi'an, China
| | - Minghong Shi
- School of Stomatology, The Third Affiliated Hospital of Xinxiang Medical University, Xinxiang, China
| | - Haotian Ren
- Department of Stomatology, Changhai Hospital, The Second Military Medical University, Shanghai, China
| | - Mianjiao Xie
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi International Joint Research Center for Oral Diseases, Department of Oral Anatomy and Physiology, School of Stomatology, The Fourth Military Medical University, Xi'an, China
| | - Chunkui Zhang
- Department of Anatomy, Histology and Embryology and K.K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China
| | - Dongmei Wang
- School of Stomatology, The Third Affiliated Hospital of Xinxiang Medical University, Xinxiang, China
| | - Xiaodong Liu
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi International Joint Research Center for Oral Diseases, Department of Oral Anatomy and Physiology, School of Stomatology, The Fourth Military Medical University, Xi'an, China
| | - Jinlian Li
- Department of Anatomy, Histology and Embryology and K.K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China
| | - Meiqing Wang
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi International Joint Research Center for Oral Diseases, Department of Oral Anatomy and Physiology, School of Stomatology, The Fourth Military Medical University, Xi'an, China.,School of Stomatology, The Third Affiliated Hospital of Xinxiang Medical University, Xinxiang, China
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7
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Du X, Li J, Li M, Yang X, Qi Z, Xu B, Liu W, Xu Z, Deng Y. Research progress on the role of type I vesicular glutamate transporter (VGLUT1) in nervous system diseases. Cell Biosci 2020; 10:26. [PMID: 32158532 PMCID: PMC7057577 DOI: 10.1186/s13578-020-00393-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 02/24/2020] [Indexed: 12/14/2022] Open
Abstract
Glutamate (Glu) is the predominant excitatory neurotransmitter in the central nervous system (CNS). Glutamatergic transmission is critical for controlling neuronal activity. In presynaptic neurons, Glu is stored in synaptic vesicles and released by stimulation. The homeostasis of glutamatergic system is maintained by a set of transporters in the membrane of synaptic vesicles. The family of vesicular Glu transporters in mammals is comprised of three highly homologous proteins: VGLUT1-3. Among them, VGLUT1 accounts for the largest proportion. However, most of the Glu is transported into the synaptic vesicles via the type 1 vesicle Glu transporter (VGLUT1). So, the expression of particular VGLUT1 is largely complementary with limited overlap and so far it is most specific markers for neurons that use Glu as neurotransmitter. Controlling the activity of VGLUT1 could potentially modulate the efficiency of excitatory neuro-transmission and change the filling level of synaptic vesicles. This review summarizes the recent knowledge concerning molecular and functional characteristic of VGLUT1, their development, contribution to a series of central nervous system and peripheral nervous system diseases such as learning and memory disorders, Alzheimer's disease, Parkinson's disease and sensitized nociception or pain pathology et al.
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Affiliation(s)
- Xianchao Du
- Department of Environmental Health, School of Public Health, China Medical University, Shenyang, 110122 Liaoning People’s Republic of China
| | - Jiashuo Li
- Department of Environmental Health, School of Public Health, China Medical University, Shenyang, 110122 Liaoning People’s Republic of China
| | - Minghui Li
- Department of Environmental Health, School of Public Health, China Medical University, Shenyang, 110122 Liaoning People’s Republic of China
| | - Xinxin Yang
- Department of Environmental Health, School of Public Health, China Medical University, Shenyang, 110122 Liaoning People’s Republic of China
| | - Zhipeng Qi
- Department of Environmental Health, School of Public Health, China Medical University, Shenyang, 110122 Liaoning People’s Republic of China
| | - Bin Xu
- Department of Environmental Health, School of Public Health, China Medical University, Shenyang, 110122 Liaoning People’s Republic of China
| | - Wei Liu
- Department of Environmental Health, School of Public Health, China Medical University, Shenyang, 110122 Liaoning People’s Republic of China
| | - Zhaofa Xu
- Department of Environmental Health, School of Public Health, China Medical University, Shenyang, 110122 Liaoning People’s Republic of China
| | - Yu Deng
- Department of Environmental Health, School of Public Health, China Medical University, Shenyang, 110122 Liaoning People’s Republic of China
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8
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Park SK, Hong JH, Jung JK, Ko HG, Bae YC. Vesicular Glutamate Transporter 1 (VGLUT1)- and VGLUT2-containing Terminals on the Rat Jaw-closing γ-Motoneurons. Exp Neurobiol 2019; 28:451-457. [PMID: 31495074 PMCID: PMC6751869 DOI: 10.5607/en.2019.28.4.451] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2019] [Revised: 05/22/2019] [Accepted: 07/08/2019] [Indexed: 11/19/2022] Open
Abstract
Currently, compared to jaw-closing (JC) α-motoneurons, the information on the distribution and morphology of glutamatergic synapses on the jaw-closing (JC) γ-motoneurons, which may help elucidate the mechanism of isometric contraction of the JC muscle, is very limited. This study investigated the distribution and ultrastructural features of vesicular glutamate transporter 1 (VGLUT1)- and VGLUT2-immunopositive (+) axon terminals (boutons) on JC γ-motoneurons by retrograde tracing with horseradish peroxidase, electron microscopic immunocytochemistry, and quantitative analysis. About 35% of the boutons on identified JC γ-motoneurons were VGLUT+, and of those, 99% were VGLUT2+. The fraction of VGLUT1+ boutons of all boutons and the percentage of membrane of JC γ-motoneurons covered by these boutons were significantly lower than those for the JC α-motoneurons, revealed in our previous work. The bouton volume, mitochondrial volume, and active zone area of the VGLUT2+ boutons on the JC γ-motoneurons were uniformly small. These findings suggest that the JC γ-motoneurons, in contrast to the JC α-motoneurons, receive generally weak glutamatergic synaptic input almost exclusively from VGLUT2+ premotoneurons that form direct synapse with motoneurons.
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Affiliation(s)
- Sook Kyung Park
- Department of Anatomy and Neurobiology, Kyungpook National University, Daegu 41940, Korea
| | - Jae Hyun Hong
- Department of Anatomy and Neurobiology, Kyungpook National University, Daegu 41940, Korea
| | - Jae Kwang Jung
- Department of Oral Medicine, School of Dentistry, Kyungpook National University, Daegu 41940, Korea
| | - Hyoung-Gon Ko
- Department of Anatomy and Neurobiology, Kyungpook National University, Daegu 41940, Korea
| | - Yong Chul Bae
- Department of Anatomy and Neurobiology, Kyungpook National University, Daegu 41940, Korea
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Liu X, Zhou KX, Yin NN, Zhang CK, Shi MH, Zhang HY, Wang DM, Xu ZJ, Zhang JD, Li JL, Wang MQ. Malocclusion Generates Anxiety-Like Behavior Through a Putative Lateral Habenula-Mesencephalic Trigeminal Nucleus Pathway. Front Mol Neurosci 2019; 12:174. [PMID: 31427925 PMCID: PMC6689965 DOI: 10.3389/fnmol.2019.00174] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 07/01/2019] [Indexed: 01/06/2023] Open
Abstract
Malocclusion is an important risk factor for temporomandibular disorder (TMD), a series of disorders characterized by dysfunction in the orofacial region involving the temporomandibular joint (TMJ) and jaw muscles. We recently showed that experimental unilateral anterior crossbite (UAC) produced masseter hyperactivity through a circuit involving the periodontal proprioception, trigeminal mesencephalic nucleus (Vme), and trigeminal motor nucleus (Vmo). Anxiety is a common complication in patients with TMD. The lateral habenula (LHb) is involved in emotional modulation and has direct projections to the Vme. Therefore, the present research examined whether UAC facilitates excitatory input from the LHb to the Vme and, subsequently, anxiety-like behaviors in rats. The LHb activation was evaluated by the electrophysiological recording, assessment of vesicular glutamate transporter-2 (VGLUT2) mRNA expression, and measurement of anxiety-like behaviors. The effects of LHb activity on Vme were evaluated by electrophysiological recording from Vme neurons and local changes in VGLUT2 protein density. UAC produced anxiety in modeled rats and increased neuronal activity in the LHb. VGLUT2 mRNA expression was also increased in the LHb. Further, VGLUT2-positive boutons were observed in close apposite upon parvalbumin (PV)-labeled Vme neurons. VGLUT2 protein expression was also increased in the Vme. Significantly, injection of VGLUT2-targeted shRNA into the LHb reduced the expression of VGLUT2 protein in the Vme, attenuated UAC-associated anxiety-like behaviors, and attenuated electrophysiological changes in the Vme neurons. In conclusion, we show that UAC activates the LHb neurons as well as the periodontal proprioceptive pathway to provide excitatory input to the Vme and produce anxiety in rats. These findings provide a rationale for suppressing activity of the LHb to attenuate both the physical and psychological effects of TMD.
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Affiliation(s)
- Xin Liu
- State Key Laboratory of Military Stomatology, Department of Oral Anatomy and Physiology, National Clinical Research Center for Oral Diseases & Shaanxi International Joint Research Center for Oral Diseases, School of Stomatology, The Fourth Military Medical University, Xi'an, China.,Department of Stomatology, The 960th Hospital of People's Liberation Army, Jinan, China
| | - Kai-Xiang Zhou
- Department of Anatomy, Histology and Embryology and K.K. Leung Brain Research Center, The Fourth Military Medical University, Xi'an, China
| | - Nan-Nan Yin
- Department of Stomatology, The 960th Hospital of People's Liberation Army, Jinan, China
| | - Chun-Kui Zhang
- Department of Anatomy, Histology and Embryology and K.K. Leung Brain Research Center, The Fourth Military Medical University, Xi'an, China
| | - Ming-Hong Shi
- State Key Laboratory of Military Stomatology, Department of Oral Anatomy and Physiology, National Clinical Research Center for Oral Diseases & Shaanxi International Joint Research Center for Oral Diseases, School of Stomatology, The Fourth Military Medical University, Xi'an, China
| | - Hong-Yun Zhang
- State Key Laboratory of Military Stomatology, Department of Oral Anatomy and Physiology, National Clinical Research Center for Oral Diseases & Shaanxi International Joint Research Center for Oral Diseases, School of Stomatology, The Fourth Military Medical University, Xi'an, China
| | - Dong-Mei Wang
- Department of Oral Medicine, School of Stomatology, Xinxiang Medical University, Xinxiang, China
| | - Zi-Jun Xu
- School of Clinical Medicine, University of South China, Hengyang, China
| | - Jing-Dong Zhang
- Department of Anesthesiology, University of Cincinnati Medical College of Medicine, Cincinnati, OH, United States
| | - Jin-Lian Li
- Department of Anatomy, Histology and Embryology and K.K. Leung Brain Research Center, The Fourth Military Medical University, Xi'an, China
| | - Mei-Qing Wang
- State Key Laboratory of Military Stomatology, Department of Oral Anatomy and Physiology, National Clinical Research Center for Oral Diseases & Shaanxi International Joint Research Center for Oral Diseases, School of Stomatology, The Fourth Military Medical University, Xi'an, China
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10
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Paik SK, Yoo HI, Choi SK, Bae JY, Park SK, Bae YC. Distribution of excitatory and inhibitory axon terminals on the rat hypoglossal motoneurons. Brain Struct Funct 2019; 224:1767-1779. [PMID: 31006070 DOI: 10.1007/s00429-019-01874-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 04/11/2019] [Indexed: 12/19/2022]
Abstract
Detailed information about the excitatory and inhibitory synapses on the hypoglossal motoneurons may help understand the neural mechanism for control of the hypoglossal motoneuron excitability and hence the precise and coordinated movements of the tongue during chewing, swallowing and licking. For this, we investigated the distribution of GABA-, glycine (Gly)- and glutamate (Glut)-immunopositive (+) axon terminals on the genioglossal (GG) motoneurons by retrograde tracing, electron microscopic immunohistochemistry, and quantitative analysis. Small GG motoneurons (< 400 μm2 in cross-sectional area) had fewer primary dendrites, significantly higher nuclear/cytoplasmic ratio, and smaller membrane area covered by synaptic boutons than large GG motoneurons (> 400 μm2). The fraction of inhibitory boutons (GABA + only, Gly + only, and mixed GABA +/Gly + boutons) of all boutons was significantly higher for small GG motoneurons than for large ones, whereas the fraction of Glut + boutons was significantly higher for large GG motoneurons than for small ones. Almost all boutons (> 95%) on both small and large GG motoneurons were GABA + , Gly + or Glut + . The frequency of mixed GABA +/Gly + boutons was the highest among inhibitory boutons types for both small and large GG motoneurons. These findings may elucidate the anatomical substrate for precise regulation of the motoneuron firing required for the fine movements of the tongue, and also suggest that the excitability of small and large GG motoneurons may be regulated differently.
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Affiliation(s)
- Sang Kyoo Paik
- Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, 188-1, 2-Ga, Samdeok-Dong, Jung-Gu, Daegu, 700-412, South Korea
| | - Hong Il Yoo
- Department of Anatomy and Neuroscience, College of Medicine, Eulji University, 77 Gyeryong-ro 771 beon-gil, Jung-Gu, Daejeon, 34824, South Korea
| | - Seung Ki Choi
- Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, 188-1, 2-Ga, Samdeok-Dong, Jung-Gu, Daegu, 700-412, South Korea
| | - Jin Young Bae
- Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, 188-1, 2-Ga, Samdeok-Dong, Jung-Gu, Daegu, 700-412, South Korea
| | - Sook Kyung Park
- Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, 188-1, 2-Ga, Samdeok-Dong, Jung-Gu, Daegu, 700-412, South Korea
| | - Yong Chul Bae
- Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, 188-1, 2-Ga, Samdeok-Dong, Jung-Gu, Daegu, 700-412, South Korea.
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11
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Liu X, Zhang C, Liu Q, Zhou K, Yin N, Zhang H, Shi M, Liu X, Wang M. Dental malocclusion stimulates neuromuscular circuits associated with temporomandibular disorders. Eur J Oral Sci 2018; 126:466-475. [DOI: 10.1111/eos.12579] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Xin Liu
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi International Joint Research Center for Oral Diseases; Department of Oral Anatomy and Physiology; School of Stomatology; The Fourth Military Medical University; Xi'an China
- Department of Stomatology; The 456th Hospital of People's Liberation Army; Jinan China
| | - Chunkui Zhang
- Department of Anatomy, Histology and Embryology and K.K. Leung Brain Research Centre; The Fourth Military Medical University; Xi'an China
| | - Qian Liu
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi International Joint Research Center for Oral Diseases; Department of Oral Anatomy and Physiology; School of Stomatology; The Fourth Military Medical University; Xi'an China
| | - Kaixiang Zhou
- Department of Anatomy, Histology and Embryology and K.K. Leung Brain Research Centre; The Fourth Military Medical University; Xi'an China
| | - Nannan Yin
- Department of Stomatology; The 456th Hospital of People's Liberation Army; Jinan China
| | - Hongyun Zhang
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi International Joint Research Center for Oral Diseases; Department of Oral Anatomy and Physiology; School of Stomatology; The Fourth Military Medical University; Xi'an China
| | - Minghong Shi
- School of Stomatology; The Third Affiliated Hospital of Xinxiang Medical University; Xinxiang China
| | - Xiaodong Liu
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi International Joint Research Center for Oral Diseases; Department of Oral Anatomy and Physiology; School of Stomatology; The Fourth Military Medical University; Xi'an China
| | - Meiqing Wang
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi International Joint Research Center for Oral Diseases; Department of Oral Anatomy and Physiology; School of Stomatology; The Fourth Military Medical University; Xi'an China
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12
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Zhang FX, Ge SN, Dong YL, Shi J, Feng YP, Li Y, Li YQ, Li JL. Vesicular glutamate transporter isoforms: The essential players in the somatosensory systems. Prog Neurobiol 2018; 171:72-89. [PMID: 30273635 DOI: 10.1016/j.pneurobio.2018.09.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 08/28/2018] [Accepted: 09/23/2018] [Indexed: 02/08/2023]
Abstract
In nervous system, glutamate transmission is crucial for centripetal conveyance and cortical perception of sensory signals of different modalities, which necessitates vesicular glutamate transporters 1-3 (VGLUT 1-3), the three homologous membrane-bound protein isoforms, to load glutamate into the presysnaptic vesicles. These VGLUTs, especially VGLUT1 and VGLUT2, selectively label and define functionally distinct neuronal subpopulations at each relay level of the neural hierarchies comprising spinal and trigeminal sensory systems. In this review, by scrutinizing each structure of the organism's fundamental hierarchies including dorsal root/trigeminal ganglia, spinal dorsal horn/trigeminal sensory nuclear complex, somatosensory thalamic nuclei and primary somatosensory cortex, we summarize and characterize in detail within each relay the neuronal clusters expressing distinct VGLUT protein/transcript isoforms, with respect to their regional distribution features (complementary distribution in some structures), axonal terminations/peripheral innervations and physiological functions. Equally important, the distribution pattern and characteristics of VGLUT1/VGLUT2 axon terminals within these structures are also epitomized. Finally, the correlation of a particular VGLUT isoform and its physiological role, disclosed thus far largely via studying the peripheral receptors, is generalized by referring to reports on global and conditioned VGLUT-knockout mice. Also, researches on VGLUTs relating to future direction are tentatively proposed, such as unveiling the elusive differences between distinct VGLUTs in mechanism and/or pharmacokinetics at ionic/molecular level, and developing VGLUT-based pain killers.
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Affiliation(s)
- Fu-Xing Zhang
- Department of Anatomy and K.K. Leung Brain Research Centre, School of Basic Medicine, The Fourth Military Medical University, Xi'an 710032, PR China
| | - Shun-Nan Ge
- Department of Anatomy and K.K. Leung Brain Research Centre, School of Basic Medicine, The Fourth Military Medical University, Xi'an 710032, PR China; Department of Neurosurgery, Tangdu Hospital, The Fourth Military Medical University, Xi'an 710038, PR China
| | - Yu-Lin Dong
- Department of Anatomy and K.K. Leung Brain Research Centre, School of Basic Medicine, The Fourth Military Medical University, Xi'an 710032, PR China
| | - Juan Shi
- Department of Anatomy and K.K. Leung Brain Research Centre, School of Basic Medicine, The Fourth Military Medical University, Xi'an 710032, PR China
| | - Yu-Peng Feng
- Department of Anatomy and K.K. Leung Brain Research Centre, School of Basic Medicine, The Fourth Military Medical University, Xi'an 710032, PR China
| | - Yang Li
- Department of Neurosurgery, Tangdu Hospital, The Fourth Military Medical University, Xi'an 710038, PR China
| | - Yun-Qing Li
- Department of Anatomy and K.K. Leung Brain Research Centre, School of Basic Medicine, The Fourth Military Medical University, Xi'an 710032, PR China; Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, PR China.
| | - Jin-Lian Li
- Department of Anatomy and K.K. Leung Brain Research Centre, School of Basic Medicine, The Fourth Military Medical University, Xi'an 710032, PR China.
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13
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Yoshida A, Moritani M, Nagase Y, Bae YC. Projection and synaptic connectivity of trigeminal mesencephalic nucleus neurons controlling jaw reflexes. J Oral Sci 2018. [PMID: 28637975 DOI: 10.2334/josnusd.16-0845] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
Neurons in the trigeminal mesencephalic nucleus (Vmes) receive deep sensation (proprioception) from jaw-closing muscle spindles and periodontal ligaments and project primarily to the jaw-closing motoneuron pool (jaw-closing nucleus) of the trigeminal motor nucleus and to the supratrigeminal nucleus. Numerous articles have described the morphology and physiology of the central projections of Vmes afferents originating from the muscle spindles and periodontal ligaments. However, no report has provided a detailed description of projection and synaptic connectivity, especially of single afferents, and their functional implications. In this review, we reanalyze data obtained by single intra-axonal recording and labeling of functionally identified Vmes muscle spindle afferents and periodontal ligament afferents and by electron microscopic observation of their projection features and synaptic organization of boutons, to compare the data for the jaw-closing nucleus and supratrigeminal nucleus. Our analysis shows that each Vmes afferent type has characteristic projection pattern and synaptic feature that may be important in jaw-reflex control.
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Affiliation(s)
- Atsushi Yoshida
- Department of Oral Anatomy and Neurobiology, Graduate School of Dentistry, Osaka University
| | - Masayuki Moritani
- Department of Physical Therapy, Faculty of Health Science, Morinomiya University of Medical Sciences
| | - Yoshitaka Nagase
- Department of Acupuncture, Takarazuka University of Medical and Health Care
| | - Yong Chul Bae
- Department of Anatomy, School of Dentistry, Kyungpook National University
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14
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Vesicular glutamate transporter 1 (VGLUT1)- and VGLUT2-immunopositive axon terminals on the rat jaw-closing and jaw-opening motoneurons. Brain Struct Funct 2018; 223:2323-2334. [DOI: 10.1007/s00429-018-1636-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 02/19/2018] [Indexed: 12/16/2022]
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15
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Synapse Formation in Monosynaptic Sensory-Motor Connections Is Regulated by Presynaptic Rho GTPase Cdc42. J Neurosci 2017; 36:5724-35. [PMID: 27225763 DOI: 10.1523/jneurosci.2146-15.2016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 04/13/2016] [Indexed: 01/04/2023] Open
Abstract
UNLABELLED Spinal reflex circuit development requires the precise regulation of axon trajectories, synaptic specificity, and synapse formation. Of these three crucial steps, the molecular mechanisms underlying synapse formation between group Ia proprioceptive sensory neurons and motor neurons is the least understood. Here, we show that the Rho GTPase Cdc42 controls synapse formation in monosynaptic sensory-motor connections in presynaptic, but not postsynaptic, neurons. In mice lacking Cdc42 in presynaptic sensory neurons, proprioceptive sensory axons appropriately reach the ventral spinal cord, but significantly fewer synapses are formed with motor neurons compared with wild-type mice. Concordantly, electrophysiological analyses show diminished EPSP amplitudes in monosynaptic sensory-motor circuits in these mutants. Temporally targeted deletion of Cdc42 in sensory neurons after sensory-motor circuit establishment reveals that Cdc42 does not affect synaptic transmission. Furthermore, addition of the synaptic organizers, neuroligins, induces presynaptic differentiation of wild-type, but not Cdc42-deficient, proprioceptive sensory neurons in vitro Together, our findings demonstrate that Cdc42 in presynaptic neurons is required for synapse formation in monosynaptic sensory-motor circuits. SIGNIFICANCE STATEMENT Group Ia proprioceptive sensory neurons form direct synapses with motor neurons, but the molecular mechanisms underlying synapse formation in these monosynaptic sensory-motor connections are unknown. We show that deleting Cdc42 in sensory neurons does not affect proprioceptive sensory axon targeting because axons reach the ventral spinal cord appropriately, but these neurons form significantly fewer presynaptic terminals on motor neurons. Electrophysiological analysis further shows that EPSPs are decreased in these mice. Finally, we demonstrate that Cdc42 is involved in neuroligin-dependent presynaptic differentiation of proprioceptive sensory neurons in vitro These data suggest that Cdc42 in presynaptic sensory neurons is essential for proper synapse formation in the development of monosynaptic sensory-motor circuits.
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16
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Verstegen AMJ, Vanderhorst V, Gray PA, Zeidel ML, Geerling JC. Barrington's nucleus: Neuroanatomic landscape of the mouse "pontine micturition center". J Comp Neurol 2017; 525:2287-2309. [PMID: 28340519 PMCID: PMC5832452 DOI: 10.1002/cne.24215] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 03/16/2017] [Accepted: 03/17/2017] [Indexed: 12/12/2022]
Abstract
Barrington's nucleus (Bar) is thought to contain neurons that trigger voiding and thereby function as the "pontine micturition center." Lacking detailed information on this region in mice, we examined gene and protein markers to characterize Bar and the neurons surrounding it. Like rats and cats, mice have an ovoid core of medium-sized Bar neurons located medial to the locus coeruleus (LC). Bar neurons express a GFP reporter for Vglut2, develop from a Math1/Atoh1 lineage, and exhibit immunoreactivity for NeuN. Many neurons in and around this core cluster express a reporter for corticotrophin-releasing hormone (BarCRH ). Axons from BarCRH neurons project to the lumbosacral spinal cord and ramify extensively in two regions: the dorsal gray commissural and intermediolateral nuclei. BarCRH neurons have unexpectedly long dendrites, which may receive synaptic input from the cerebral cortex and other brain regions beyond the core afferents identified previously. Finally, at least five populations of neurons surround Bar: rostral-dorsomedial cholinergic neurons in the laterodorsal tegmental nucleus; lateral noradrenergic neurons in the LC; medial GABAergic neurons in the pontine central gray; ventromedial, small GABAergic neurons that express FoxP2; and dorsolateral glutamatergic neurons that express FoxP2 in the pLC and form a wedge dividing Bar from the dorsal LC. We discuss the implications of this new information for interpreting existing data and future experiments targeting BarCRH neurons and their synaptic afferents to study micturition and other pelvic functions.
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Affiliation(s)
- Anne M. J. Verstegen
- Department of Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts
- Division of Endocrinology, Beth Israel Deaconess Medical Center, Boston, Massachusetts
- Department of Medicine & Neurology, Harvard Medical School, Boston, Massachusetts
| | - Veronique Vanderhorst
- Department of Medicine & Neurology, Harvard Medical School, Boston, Massachusetts
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, Massachusetts
| | - Paul A. Gray
- Department of Anatomy & Neurobiology, Washington University School of Medicine, Saint Louis, Missouri
- Indigo Ag, Inc., Charlestown, Massachusetts
| | - Mark L. Zeidel
- Department of Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts
- Department of Medicine & Neurology, Harvard Medical School, Boston, Massachusetts
| | - Joel C. Geerling
- Department of Medicine & Neurology, Harvard Medical School, Boston, Massachusetts
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, Massachusetts
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17
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Geerling JC, Yokota S, Rukhadze I, Roe D, Chamberlin NL. Kölliker-Fuse GABAergic and glutamatergic neurons project to distinct targets. J Comp Neurol 2017; 525:1844-1860. [PMID: 28032634 DOI: 10.1002/cne.24164] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 10/16/2016] [Accepted: 10/31/2016] [Indexed: 01/01/2023]
Abstract
The Kölliker-Fuse nucleus (KF) is known primarily for its respiratory function as the "pneumotaxic center" or "pontine respiratory group." Considered part of the parabrachial (PB) complex, KF contains glutamatergic neurons that project to respiratory-related targets in the medulla and spinal cord (Yokota, Oka, Tsumori, Nakamura, & Yasui, 2007). Here we describe an unexpected population of neurons in the caudal KF and adjacent lateral crescent subnucleus (PBlc), which are γ-aminobutyric acid (GABA)ergic and have an entirely different pattern of projections than glutamatergic KF neurons. First, immunofluorescence, in situ hybridization, and Cre-reporter labeling revealed that many of these GABAergic neurons express FoxP2 in both rats and mice. Next, using Cre-dependent axonal tracing in Vgat-IRES-Cre and Vglut2-IRES-Cre mice, we identified different projection patterns from GABAergic and glutamatergic neurons in this region. GABAergic neurons in KF and PBlc project heavily and almost exclusively to trigeminal sensory nuclei, with minimal projections to cardiorespiratory nuclei in the brainstem, and none to the spinal cord. In contrast, glutamatergic KF neurons project heavily to the autonomic, respiratory, and motor regions of the medulla and spinal cord previously identified as efferent targets mediating KF cardiorespiratory effects. These findings identify a novel, GABAergic subpopulation of KF/PB neurons with a distinct efferent projection pattern targeting the brainstem trigeminal sensory system. Rather than regulating breathing, we propose that these neurons influence vibrissal sensorimotor function.
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Affiliation(s)
- Joel C Geerling
- Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts.,Division of Sleep Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts.,Department of Neurology, University of Iowa Hospital and Clinics, Iowa City, Iowa
| | - Shigefumi Yokota
- Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts.,Department of Anatomy and Morphological Neuroscience, Shimane University School of Medicine, Izumo, Japan
| | - Irma Rukhadze
- Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts.,Division of Sleep Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts.,V.A. Greater Los Angeles Healthcare System, Los Angeles, California.,Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Dan Roe
- Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts
| | - Nancy L Chamberlin
- Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts.,Division of Sleep Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts
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18
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Liu X, Zhang C, Wang D, Zhang H, Liu X, Li J, Wang M. Proprioceptive mechanisms in occlusion-stimulated masseter hypercontraction. Eur J Oral Sci 2017; 125:127-134. [PMID: 28145597 DOI: 10.1111/eos.12331] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/09/2016] [Indexed: 12/12/2022]
Abstract
Neurons in the trigeminal mesencephalic nucleus (Vme) have an axon that branches peripherally to innervate the orofacial region and projects centrally to the trigeminal motor nucleus (Vmo). They function as the primary neurons conveying proprioceptive messages. The present study aimed to demonstrate the presence of a periodontal-Vme-Vmo circuit and to provide evidence for its involvement in an experimental unilateral anterior crossbite (UAC) model, which can induce osteoarthritis in the temporomandibular joint. Cholera toxin B subunit (CTb) was injected into the inferior alveolar nerve of rats to help identify the central axon terminals of Vme neurons in the Vmo. The levels of vesicular glutamate transporter 1 (VGLUT1) expressed in the periodontal region, Vme, Vmo, and masseter, and the level of acetylcholinesterase (AChE) expressed in the masseter, were assessed in UAC rats and controls. In CTb-treated rats, many CTb-labeled cell bodies and endings were identified in the Vme and in the Vmo, respectively. In UAC rats, VGLUT1 was expressed at a statistically significantly higher level in the periodontal ligament, Vme, Vmo, and masseter than it was in control rats. The level of AChE protein was 1.97 times higher in UAC rat masseter compared with control rat masseter. These findings reveal a trigeminal mechanism underlying masseter hyperactivity induced by an altered occlusion.
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Affiliation(s)
- Xin Liu
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi International Joint Research Center for Oral Diseases, Department of Oral Anatomy and Physiology, School of Stomatology, The Fourth Military Medical University, Xi'an, China
| | - Chunkui Zhang
- Department of Anatomy, Histology and Embryology and K.K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China
| | - Dongmei Wang
- School of Stomatology, The Third Affiliated Hospital of Xinxiang Medical University, Xinxiang, China
| | - Hongyun Zhang
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi International Joint Research Center for Oral Diseases, Department of Oral Anatomy and Physiology, School of Stomatology, The Fourth Military Medical University, Xi'an, China
| | - Xiaodong Liu
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi International Joint Research Center for Oral Diseases, Department of Oral Anatomy and Physiology, School of Stomatology, The Fourth Military Medical University, Xi'an, China
| | - Jinlian Li
- Department of Anatomy, Histology and Embryology and K.K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China
| | - Meiqing Wang
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi International Joint Research Center for Oral Diseases, Department of Oral Anatomy and Physiology, School of Stomatology, The Fourth Military Medical University, Xi'an, China
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Descending control of itch transmission by the serotonergic system via 5-HT1A-facilitated GRP-GRPR signaling. Neuron 2014; 84:821-34. [PMID: 25453842 DOI: 10.1016/j.neuron.2014.10.003] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/26/2014] [Indexed: 12/26/2022]
Abstract
UNLABELLED Central serotonin (5-hydroxytryptophan, 5-HT) modulates somatosensory transduction, but how it achieves sensory modality-specific modulation remains unclear. Here we report that enhancing serotonergic tone via administration of 5-HT potentiates itch sensation, whereas mice lacking 5-HT or serotonergic neurons in the brainstem exhibit markedly reduced scratching behavior. Through pharmacological and behavioral screening, we identified 5-HT1A as a key receptor in facilitating gastrin-releasing peptide (GRP)-dependent scratching behavior. Coactivation of 5-HT1A and GRP receptors (GRPR) greatly potentiates subthreshold, GRP-induced Ca(2+) transients, and action potential firing of GRPR(+) neurons. Immunostaining, biochemical, and biophysical studies suggest that 5-HT1A and GRPR may function as receptor heteromeric complexes. Furthermore, 5-HT1A blockade significantly attenuates, whereas its activation contributes to, long-lasting itch transmission. Thus, our studies demonstrate that the descending 5-HT system facilitates GRP-GRPR signaling via 5-HT1A to augment itch-specific outputs, and a disruption of crosstalk between 5-HT1A and GRPR may be a useful antipruritic strategy. VIDEO ABSTRACT
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20
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Csaba Z, Krejci E, Bernard V. Postsynaptic muscarinic m2 receptors at cholinergic and glutamatergic synapses of mouse brainstem motoneurons. J Comp Neurol 2013. [PMID: 23184757 DOI: 10.1002/cne.23268] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
In many brain areas, few cholinergic synapses are identified. Acetylcholine is released into the extracellular space and acts through diffuse transmission. Motoneurons, however, are contacted by numerous cholinergic terminals, indicating synaptic cholinergic transmission on them. The muscarinic m2 receptor is the major acetylcholine receptor subtype of motoneurons; therefore, we analyzed the localization of the m2 receptor in correlation with synapses by electron microscopic immunohistochemistry in the mouse trigeminal, facial, and hypoglossal motor nuclei. In all nuclei, m2 receptors were localized at the membrane of motoneuronal perikarya and dendrites. The m2 receptors were concentrated at cholinergic synapses located on the perikarya and most proximal dendrites. However, m2 receptors at cholinergic synapses represented only a minority (<10%) of surface m2 receptors. The m2 receptors were also enriched at glutamatergic synapses in both motoneuronal perikarya and dendrites. A relatively large proportion (20-30%) of plasma membrane-associated m2 receptors were located at glutamatergic synapses. In conclusion, the effect of acetylcholine on motoneuron populations might be mediated through a synaptic as well as diffuse type of transmission.
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Affiliation(s)
- Zsolt Csaba
- Université Paris Descartes, 75006 Paris, France.
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Vesicular Glutamate Transporters in Axons That Innervate the Human Dental Pulp. J Endod 2012; 38:470-4. [DOI: 10.1016/j.joen.2011.12.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Revised: 12/07/2011] [Accepted: 12/08/2011] [Indexed: 11/15/2022]
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Paik SK, Kwak WK, Bae JY, Na YK, Park SY, Yi HW, Ahn DK, Ottersen OP, Yoshida A, Bae YC. Development of γ-aminobutyric acid-, glycine-, and glutamate-immunopositive boutons on rat jaw-opening motoneurons. J Comp Neurol 2012; 520:1212-26. [DOI: 10.1002/cne.22771] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Li Z, Ge S, Zhang F, Zhang T, Mizuno N, Hioki H, Kaneko T, Gao G, Li J. Distribution of Gephyrin-Immunoreactivity in the Trigeminal Motor Nucleus: An Immunohistochemical Study in Rats. Anat Rec (Hoboken) 2012; 295:641-51. [DOI: 10.1002/ar.22426] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Accepted: 01/10/2012] [Indexed: 11/11/2022]
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Honma S, Kato A, Shi L, Yatani H, Wakisaka S. Vesicular Glutamate Transporter Immunoreactivity in the Periodontal Ligament of the Rat Incisor. Anat Rec (Hoboken) 2011; 295:160-6. [DOI: 10.1002/ar.21465] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2011] [Accepted: 06/26/2011] [Indexed: 11/10/2022]
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Zhang F, Pang Y, Zhang M, Zhang T, Dong Y, Lai C, Shum D, Chan Y, Li J, Li Y. Expression of vesicular glutamate transporters in peripheral vestibular structures and vestibular nuclear complex of rat. Neuroscience 2011; 173:179-89. [DOI: 10.1016/j.neuroscience.2010.11.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2010] [Revised: 11/08/2010] [Accepted: 11/09/2010] [Indexed: 11/17/2022]
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Abstract
The main text of this chapter, written by James P. Lund, summarizes most of the work related to the neural control of mastication that he conducted with his collaborators throughout the years. From his early PhD work showing that mastication is centrally patterned to his latest work related to the interaction between pain and movement, Lund will have addressed many essential questions regarding the organization and functioning of the masticatory central pattern generator (CPG). His earliest studies examined how the CPG modulates reflexes and the excitability of primary afferents, interneurons, and motoneurons forming their circuitry. He then tackled the question of how the CPG itself was modulated by different types of sensory and cortical inputs. Another series of studies focused on the organization of the subpopulations of neurons forming the CPG, their intrinsic and network properties. Shortly before his untimely passing, he had turned his attention to the potential contribution of muscle spindle afferents to the patterning of mastication as well as to the development of chronic muscle pain.
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Affiliation(s)
- James P Lund
- Faculty of Dentistry, McGill University, Montreal, Quebec, Canada
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Lund JP, Sadeghi S, Athanassiadis T, Caram Salas N, Auclair F, Thivierge B, Arsenault I, Rompré P, Westberg KG, Kolta A. Assessment of the potential role of muscle spindle mechanoreceptor afferents in chronic muscle pain in the rat masseter muscle. PLoS One 2010; 5:e11131. [PMID: 20559566 PMCID: PMC2886111 DOI: 10.1371/journal.pone.0011131] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2009] [Accepted: 05/11/2010] [Indexed: 12/02/2022] Open
Abstract
Background The phenotype of large diameter sensory afferent neurons changes in several models of neuropathic pain. We asked if similar changes also occur in “functional” pain syndromes. Methodology/Principal Findings Acidic saline (AS, pH 4.0) injections into the masseter muscle were used to induce persistent myalgia. Controls received saline at pH 7.2. Nocifensive responses of Experimental rats to applications of Von Frey Filaments to the masseters were above control levels 1–38 days post-injection. This effect was bilateral. Expression of c-Fos in the Trigeminal Mesencephalic Nucleus (NVmes), which contains the somata of masseter muscle spindle afferents (MSA), was above baseline levels 1 and 4 days after AS. The resting membrane potentials of neurons exposed to AS (n = 167) were hyperpolarized when compared to their control counterparts (n = 141), as were their thresholds for firing, high frequency membrane oscillations (HFMO), bursting, inward and outward rectification. The amplitude of HFMO was increased and spontaneous ectopic firing occurred in 10% of acid-exposed neurons, but never in Controls. These changes appeared within the same time frame as the observed nocifensive behaviour. Ectopic action potentials can travel centrally, but also antidromically to the peripheral terminals of MSA where they could cause neurotransmitter release and activation of adjacent fibre terminals. Using immunohistochemistry, we confirmed that annulospiral endings of masseter MSA express the glutamate vesicular transporter VGLUT1, indicating that they can release glutamate. Many capsules also contained fine fibers that were labelled by markers associated with nociceptors (calcitonin gene-related peptide, Substance P, P2X3 receptors and TRPV1 receptors) and that expressed the metabotropic glutamate receptor, mGluR5. Antagonists of glutamatergic receptors given together with the 2nd injection of AS prevented the hypersensitivity observed bilaterally but were ineffective if given contralaterally. Conclusions/Significance Low pH leads to changes in several electrical properties of MSA, including initiation of ectopic action potentials which could propagate centrally but could also invade the peripheral endings causing glutamate release and activation of nearby nociceptors within the spindle capsule. This peripheral drive could contribute both to the transition to, and maintenance of, persistent muscle pain as seen in some “functional” pain syndromes.
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Affiliation(s)
- James P Lund
- Groupe de Recherche sur le Système Nerveux Central du Fonds de Recherche en Santé du Québec, Department of Physiology, Université de Montréal, Montréal, Québec, Canada
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Ge SN, Ma YF, Hioki H, Wei YY, Kaneko T, Mizuno N, Gao GD, Li JL. Coexpression of VGLUT1 and VGLUT2 in trigeminothalamic projection neurons in the principal sensory trigeminal nucleus of the rat. J Comp Neurol 2010; 518:3149-68. [DOI: 10.1002/cne.22389] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Hioki H, Nakamura H, Ma YF, Konno M, Hayakawa T, Nakamura KC, Fujiyama F, Kaneko T. Vesicular glutamate transporter 3-expressing nonserotonergic projection neurons constitute a subregion in the rat midbrain raphe nuclei. J Comp Neurol 2009; 518:668-86. [DOI: 10.1002/cne.22237] [Citation(s) in RCA: 165] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Pang YW, Ge SN, Nakamura KC, Li JL, Xiong KH, Kaneko T, Mizuno N. Axon terminals expressing vesicular glutamate transporter VGLUT1 or VGLUT2 within the trigeminal motor nucleus of the rat: Origins and distribution patterns. J Comp Neurol 2009; 512:595-612. [DOI: 10.1002/cne.21894] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Action-based body maps in the spinal cord emerge from a transitory floating organization. J Neurosci 2008; 28:5494-503. [PMID: 18495883 DOI: 10.1523/jneurosci.0651-08.2008] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
During development primary afferents grow into and establish neuronal connections in the spinal cord, thereby forming the basis for how we perceive sensory information and control our movements. In the somatosensory system, myriads of primary afferents, conveying information from different body locations and sensory modalities, get organized in the dorsal horn of the spinal cord so that spinal multisensory circuits receive topographically ordered information. How this intricate pathfinding is brought about during development is, however, largely unknown. Here we show that a body representation closely related to motor patterns emerges from a transitory floating and plastic organization through profound activity-dependent rewiring, involving both sprouting and elimination of afferent connections, and provide evidence for cross-modality interactions in the alignment of the multisensory input. Thus, far from being inborn and stereotypic, the dorsal horn of the spinal cord now appears to be a highly adaptive brain-body interface.
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Wang Y, Pang YW, Dong YL, Zhang FX, Li JL, Li YQ. Localization of vesicular glutamate transporters in the peripheral vestibular system of rat. Neurosci Bull 2007; 23:175-9. [PMID: 17612597 PMCID: PMC5550633 DOI: 10.1007/s12264-007-0026-x] [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: 10/22/2022] Open
Abstract
OBJECTIVE To examine the vesicular glutamate transporters (VGluTs: VGluT1-VGluT3) in the peripheral vestibular system. METHODS The vestibular structures, including Scarpa's ganglion (vestibular ganglion, VG), maculae of utricle and saccule, and ampullary cristae, from normal Sprague-Dawley rats were processed immunohistochemically for VGluTs, by avidin-biotinylated peroxidase complex method, with 3-3'-diaminobenzidine (DAB) as chromogen. RESULTS (1) VGluT1 was localized to partial neurons of VG and to the putative primary afferent fibers innervating vestibular end-organs. (2) Intense VGluT3 immunoreactivity was detected in large number of sensory epithelia cells, and weak labeling of VGluT3-positive afferent fibers was in the maculae and ampullary cristae. (3) No or very weak VGluT2 immunoreactivity was observed in the VG and acoustic maculae. CONCLUSION These results provide the morphological support that glutamate exists in the peripheral vestibular system, and it may play an important role in the centripetal vestibular transmission.
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Affiliation(s)
- Yuan Wang
- Department of Anatomy and K.K. Leung Brain Research Centre, The Fourth Military Medical University, Xi’an, 710032 China
- Department of Stomatology, The Fourth Military Medical University, Xi’an, 710032 China
| | - You-Wang Pang
- Department of Anatomy and K.K. Leung Brain Research Centre, The Fourth Military Medical University, Xi’an, 710032 China
- Department of Orthopaedics, The 180th Hospital of PLA, Quanzhou, 362000 China
| | - Yu-Lin Dong
- Department of Anatomy and K.K. Leung Brain Research Centre, The Fourth Military Medical University, Xi’an, 710032 China
| | - Fu-Xing Zhang
- Department of Anatomy and K.K. Leung Brain Research Centre, The Fourth Military Medical University, Xi’an, 710032 China
| | - Jin-Lian Li
- Department of Anatomy and K.K. Leung Brain Research Centre, The Fourth Military Medical University, Xi’an, 710032 China
| | - Yun-Qing Li
- Department of Anatomy and K.K. Leung Brain Research Centre, The Fourth Military Medical University, Xi’an, 710032 China
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Lazarov NE. Neurobiology of orofacial proprioception. ACTA ACUST UNITED AC 2007; 56:362-83. [PMID: 17915334 DOI: 10.1016/j.brainresrev.2007.08.009] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2007] [Accepted: 08/22/2007] [Indexed: 12/29/2022]
Abstract
Primary sensory fibers innervating the head region derive from neurons of both the trigeminal ganglion (TG) and mesencephalic trigeminal nucleus (MTN). The trigeminal primary proprioceptors have their cell bodies in the MTN. Unlike the TG cells, MTN neuronal somata are centrally located within the brainstem and receive synaptic inputs that potentially modify their output. They are a crucial component of the neural circuitry responsible for the generation and control of oromotor activities. Gaining an insight into the chemical neuroanatomy of the MTN is, therefore, of fundamental importance for the understanding of neurobiology of the head proprioceptive system. This paper summarizes the recent advances in our knowledge of pre- and postsynaptic mechanisms related to orofacial proprioceptive signaling in mammals. It first briefly describes the neuroanatomy of the MTN, which is involved in the processing of proprioceptive information from the face and oral cavity, and then focuses on its neurochemistry. In order to solve the puzzle of the chemical coding of the mammalian MTN, we review the expression of classical neurotransmitters and their receptors in mesencephalic trigeminal neurons. Furthermore, we discuss the relationship of neuropeptides and their corresponding receptors in relaying of masticatory proprioception and also refer to the interactions with other atypical neuromessengers and neurotrophic factors. In extension of previous inferences, we provide conclusive evidence that the levels of transmitters vary according to the environmental conditions thus implying the neuroplasticity of mesencephalic trigeminal neurons. Finally, we have also tried to give an integrated functional account of the MTN neurochemical profiles.
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Affiliation(s)
- Nikolai E Lazarov
- Department of Anatomy and Histology, Faculty of Medicine, Medical University-Sofia, 2, Zdrave Street, BG-1431 Sofia, Bulgaria.
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Hippenmeyer S, Huber RM, Ladle DR, Murphy K, Arber S. ETS Transcription Factor Erm Controls Subsynaptic Gene Expression in Skeletal Muscles. Neuron 2007; 55:726-40. [PMID: 17785180 DOI: 10.1016/j.neuron.2007.07.028] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2007] [Revised: 06/22/2007] [Accepted: 07/24/2007] [Indexed: 11/23/2022]
Abstract
Accumulation of specific proteins at synaptic structures is essential for synapse assembly and function, but mechanisms regulating local protein enrichment remain poorly understood. At the neuromuscular junction (NMJ), subsynaptic nuclei underlie motor axon terminals within extrafusal muscle fibers and are transcriptionally distinct from neighboring nuclei. In this study, we show that expression of the ETS transcription factor Erm is highly concentrated at subsynaptic nuclei, and its mutation in mice leads to severe downregulation of many genes with normally enriched subsynaptic expression. Erm mutant mice display an expansion of the muscle central domain in which acetylcholine receptor (AChR) clusters accumulate, show gradual fragmentation of AChR clusters, and exhibit symptoms of muscle weakness mimicking congenital myasthenic syndrome (CMS). Together, our findings define Erm as an upstream regulator of a transcriptional program selective to subsynaptic nuclei at the NMJ and underscore the importance of transcriptional control of local synaptic protein accumulation.
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Affiliation(s)
- Simon Hippenmeyer
- Biozentrum, Department of Cell Biology, University of Basel, Klingelbergstrasse 70, 4056 Basel, Switzerland
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Shigenaga Y, Bae YC, Moritani M, Yoshida A. Spatial distribution patterns of excitatory and inhibitory synapses in the dendritic tree differ between jaw-closing and -opening motoneurons. Arch Oral Biol 2007; 52:321-4. [PMID: 17174264 DOI: 10.1016/j.archoralbio.2006.11.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2006] [Revised: 11/02/2006] [Accepted: 11/02/2006] [Indexed: 11/23/2022]
Abstract
This paper reviews recent data on the spatial distribution of inhibitory and excitatory synapses on the dendritic tree of jaw-closing (JC) and -opening (JO) motoneurons in the cat, in which a combination of techniques employing intracellular injections of horseradish peroxidase and postembedding immunogold labelling was used. The dendritic tree is divided into three segments: primary and distal dendrites and intermediate dendrites between the two segments. The proportion of inhibitory boutons (immunoreactive for GABA and/or glycine) is slightly higher than proportion of excitatory boutons (immunoreactive for glutamate) in JC motoneurons, but this trend is reversed in JO motoneurons. In the two kinds of motoneuron, boutons immunoreactive to glycine alone are more numerous than boutons double-labelled to GABA and glycine, which, in turn, occur more frequently than boutons immunoreactive to GABA alone. In JC motoneurons, the packing density (number of boutons per 100 microm(2)) of the inhibitory boutons decreases somatofugally, but this trend is not applicable to the excitatory boutons. In contrast, the packing density of the inhibitory and excitatory boutons in JO motoneurons does not significantly differ among the three dendritic compartments, though it is slightly higher for the excitatory than the inhibitory ones on each dendritic segment. These differences have important implications for synaptic integration in JC and JO motoneurons.
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Affiliation(s)
- Yoshio Shigenaga
- Department of Oral Anatomy and Neurobiology, Graduate School of Dentistry, Osaka University, Suita, Osaka 565-0871, Japan.
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