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Lee PR, Kim J, Rossi HL, Chung S, Han SY, Kim J, Oh SB. Transcriptional profiling of dental sensory and proprioceptive trigeminal neurons using single-cell RNA sequencing. Int J Oral Sci 2023; 15:45. [PMID: 37749100 PMCID: PMC10519964 DOI: 10.1038/s41368-023-00246-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Revised: 08/30/2023] [Accepted: 08/31/2023] [Indexed: 09/27/2023] Open
Abstract
Dental primary afferent (DPA) neurons and proprioceptive mesencephalic trigeminal nucleus (MTN) neurons, located in the trigeminal ganglion and the brainstem, respectively, are essential for controlling masticatory functions. Despite extensive transcriptomic studies on various somatosensory neurons, there is still a lack of knowledge about the molecular identities of these populations due to technical challenges in their circuit-validated isolation. Here, we employed high-depth single-cell RNA sequencing (scRNA-seq) in combination with retrograde tracing in mice to identify intrinsic transcriptional features of DPA and MTN neurons. Our transcriptome analysis revealed five major types of DPA neurons with cell type-specific gene enrichment, some of which exhibit unique mechano-nociceptive properties capable of transmitting nociception in response to innocuous mechanical stimuli in the teeth. Furthermore, we discovered cellular heterogeneity within MTN neurons that potentially contribute to their responsiveness to mechanical stretch in the masseter muscle spindles. Additionally, DPA and MTN neurons represented sensory compartments with distinct molecular profiles characterized by various ion channels, receptors, neuropeptides, and mechanoreceptors. Together, our study provides new biological insights regarding the highly specialized mechanosensory functions of DPA and MTN neurons in pain and proprioception.
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Affiliation(s)
- Pa Reum Lee
- Department of Neurobiology and Physiology, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, Republic of Korea
| | - Jihoon Kim
- Genomics and Computational Biology Graduate Group, University of Pennsylvania, Philadelphia, PA, USA
| | - Heather Lynn Rossi
- Department of Pathobiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Sena Chung
- Department of Neurobiology and Physiology, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea
| | - Seung Yub Han
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Junhyong Kim
- Genomics and Computational Biology Graduate Group, University of Pennsylvania, Philadelphia, PA, USA.
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA.
| | - Seog Bae Oh
- Department of Neurobiology and Physiology, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea.
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Park SK, Devi AP, Bae JY, Cho YS, Ko HG, Kim DY, Bae YC. Synaptic connectivity of urinary bladder afferents in the rat superficial dorsal horn and spinal parasympathetic nucleus. J Comp Neurol 2019; 527:3002-3013. [PMID: 31168784 DOI: 10.1002/cne.24725] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 05/30/2019] [Accepted: 05/30/2019] [Indexed: 11/06/2022]
Abstract
That visceral sensory afferents are functionally distinct from their somatic analogues has been known for a long time but the detailed knowledge of their synaptic connections and neurotransmitters at the first relay nucleus in the spinal cord has been limited. To provide information on these topics, we investigated the synapses and neurotransmitters of identified afferents from the urinary bladder to the superficial laminae of the rat spinal dorsal horn (DH) and the spinal parasympathetic nucleus (SPN) by tracing with horseradish peroxidase, quantitative electron microscopical analysis, and immunogold staining for GABA and glycine. In the DH, most bladder afferent boutons formed synapses with 1-2 postsynaptic dendrites, whereas in the SPN, close to a half of them formed synapses with 3-8 postsynaptic dendrites. The number of postsynaptic dendrites and dendritic spines per bladder afferent bouton, both measures of synaptic divergence and of potential for synaptic plasticity at a single bouton level, were significantly higher in the SPN than in the DH. Bladder afferent boutons frequently received inhibitory axoaxonic synapses from presynaptic endings in the DH but rarely in the SPN. The presynaptic endings were GABA- and/or glycine-immunopositive. The bouton volume, mitochondrial volume, and active zone area, all determinants of synaptic strength, of the bladder afferent boutons were positively correlated with the number of postsynaptic dendrites. These findings suggest that visceral sensory information conveyed via the urinary bladder afferents is processed differently in the DH than in the SPN, and differently from the way somatosensory information is processed in the spinal cord.
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Affiliation(s)
- Sook Kyung Park
- Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, Daegu, South Korea
| | - Angom Pushparani Devi
- Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, Daegu, South Korea
| | - Jin Young Bae
- Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, Daegu, South Korea
| | - Yi Sul Cho
- Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, Daegu, South Korea
| | - Hyoung-Gon Ko
- Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, Daegu, South Korea
| | - Duk Yoon Kim
- Department of Urology, School of Medicine, Catholic University of Daegu, Daegu, South Korea
| | - Yong Chul Bae
- Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, Daegu, South Korea
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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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Bae JY, Mun CJ, Kim YS, Ahn DK, Bae YC. Quantitative ultrastructural analysis of fibers expressing parvalbumin, calretinin, calbindin D-28k, stage specific embryonic antigen-4, and phosphorylated neurofilament 200 in the peripheral sensory root of the rat trigeminal ganglion. J Comp Neurol 2018; 526:2204-2214. [DOI: 10.1002/cne.24476] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 04/02/2018] [Accepted: 05/14/2018] [Indexed: 11/07/2022]
Affiliation(s)
- Jin Young Bae
- Department of Anatomy and Neurobiology, School of Dentistry; Kyungpook National University; Daegu South Korea
| | - Cheol Ju Mun
- Department of Anatomy and Neurobiology, School of Dentistry; Kyungpook National University; Daegu South Korea
| | - Yun Sook Kim
- Department of Anatomy and Neurobiology, School of Dentistry; Kyungpook National University; Daegu South Korea
| | - Dong Kuk Ahn
- Department of Physiology, School of Dentistry; Kyungpook National University; Daegu South Korea
| | - Yong Chul Bae
- Department of Anatomy and Neurobiology, School of Dentistry; Kyungpook National University; Daegu South Korea
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Kawasaki Y, Saito M, Won J, Bae JY, Sato H, Toyoda H, Kuramoto E, Kogo M, Tanaka T, Kaneko T, Oh SB, Bae YC, Kang Y. Inhibition of GluR Current in Microvilli of Sensory Neurons via Na +-Microdomain Coupling Among GluR, HCN Channel, and Na +/K + Pump. Front Cell Neurosci 2018; 12:113. [PMID: 29740287 PMCID: PMC5928758 DOI: 10.3389/fncel.2018.00113] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 04/06/2018] [Indexed: 11/13/2022] Open
Abstract
Glutamatergic dendritic EPSPs evoked in cortical pyramidal neurons are depressed by activation of hyperpolarization-activated cyclic nucleotide-gated (HCN) channels expressed in dendritic spines. This depression has been attributed to shunting effects of HCN current (Ih) on input resistance or Ih deactivation. Primary sensory neurons in the rat mesencephalic trigeminal nucleus (MTN) have the somata covered by spine-like microvilli that express HCN channels. In rat MTN neurons, we demonstrated that Ih enhancement apparently diminished the glutamate receptor (GluR) current (IGluR) evoked by puff application of glutamate/AMPA and enhanced a transient outward current following IGluR (OT-IGluR). This suggests that some outward current opposes inward IGluR. The IGluR inhibition displayed a U-shaped voltage-dependence with a minimal inhibition around the resting membrane potential, suggesting that simple shunting effects or deactivation of Ih cannot explain the U-shaped voltage-dependence. Confocal imaging of Na+ revealed that GluR activation caused an accumulation of Na+ in the microvilli, which can cause a negative shift of the reversal potential for Ih (Eh). Taken together, it was suggested that IGluR evoked in MTN neurons is opposed by a transient decrease or increase in standing inward or outward Ih, respectively, both of which can be caused by negative shifts of Eh, as consistent with the U-shaped voltage-dependence of the IGluR inhibition and the OT-IGluR generation. An electron-microscopic immunohistochemical study revealed the colocalization of HCN channels and glutamatergic synapses in microvilli of MTN neurons, which would provide a morphological basis for the functional interaction between HCN and GluR channels. Mathematical modeling eliminated the possibilities of the involvements of Ih deactivation and/or shunting effect and supported the negative shift of Eh which causes the U-shaped voltage-dependent inhibition of IGluR.
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Affiliation(s)
- Yasuhiro Kawasaki
- Department of Neuroscience and Oral Physiology, Graduate School of Dentistry, Osaka University, Osaka, Japan
| | - Mitsuru Saito
- Department of Neuroscience and Oral Physiology, Graduate School of Dentistry, Osaka University, Osaka, Japan
| | - Jonghwa Won
- Department of Brain and Cognitive Sciences, College of Natural Sciences, Dental Research Institute and Department of Neurobiology and Physiology, School of Dentistry, Seoul National University, Seoul, South Korea
| | - Jin Young Bae
- Department of Oral Anatomy, School of Dentistry, Kyungpook National University, Daegu, South Korea
| | - Hajime Sato
- Department of Neuroscience and Oral Physiology, Graduate School of Dentistry, Osaka University, Osaka, Japan
| | - Hiroki Toyoda
- Department of Neuroscience and Oral Physiology, Graduate School of Dentistry, Osaka University, Osaka, Japan
| | - Eriko Kuramoto
- Department of Morphological Brain Science, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Mikihiko Kogo
- Department of Neuroscience and Oral Physiology, Graduate School of Dentistry, Osaka University, Osaka, Japan
| | - Takuma Tanaka
- Department of Computational Intelligence and Systems Science, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, Yokohama, Japan
| | - Takeshi Kaneko
- Department of Morphological Brain Science, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Seog Bae Oh
- Department of Brain and Cognitive Sciences, College of Natural Sciences, Dental Research Institute and Department of Neurobiology and Physiology, School of Dentistry, Seoul National University, Seoul, South Korea
| | - Yong Chul Bae
- Department of Oral Anatomy, School of Dentistry, Kyungpook National University, Daegu, South Korea
| | - Youngnam Kang
- Department of Neuroscience and Oral Physiology, Graduate School of Dentistry, Osaka University, Osaka, Japan
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Bae JY, Lee JS, Ko SJ, Cho YS, Rah JC, Cho HJ, Park MJ, Bae YC. Extrasynaptic homomeric glycine receptors in neurons of the rat trigeminal mesencephalic nucleus. Brain Struct Funct 2018; 223:2259-2268. [PMID: 29460053 DOI: 10.1007/s00429-018-1607-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Accepted: 11/29/2017] [Indexed: 12/19/2022]
Abstract
The neurons in the trigeminal mesencephalic nucleus (Vmes) innervate jaw-closing muscle spindles and periodontal ligaments, and play a crucial role in the regulation of jaw movements. Recently, it was shown that many boutons that form synapses on them are immunopositive for glycine (Gly+), suggesting that these neurons receive glycinergic input. Information about the glycine receptors that mediate this input is needed to help understand the role of glycine in controlling Vmes neuron excitability. For this, we investigated the expression of glycine receptor subunit alpha 3 (GlyRα3) and gephyrin in neurons in Vmes and the trigeminal motor nucleus (Vmo), and the Gly+ boutons that contact them by light- and electron-microscopic immunocytochemistry and quantitative ultrastructural analysis. The somata of the Vmes neurons were immunostained for GlyRα3, but not gephyrin, indicating expression of homomeric GlyR. The immunostaining for GlyRα3 was localized away from the synapses in the Vmes neuron somata, in contrast to the Vmo neurons, where the staining for GlyRα3 and gephyrin were localized at the subsynaptic zones in somata and dendrites. Additionally, the ultrastructural determinants of synaptic strength, bouton volume, mitochondrial volume, and active zone area, were significantly smaller in Gly+ boutons on the Vmes neurons than in those on the Vmo neurons. These findings support the notion that the Vmes neurons receive glycinergic input via putative extrasynaptic homomeric glycine receptors, likely mediating a slow, tonic modulation of the Vmes neuron excitability.
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Affiliation(s)
- Jin Young Bae
- Department of Anatomy and Neurobiology, School of Medicine and Dentistry, Kyungpook National University, 188-1, 2-Ga, Samdeok-Dong, Jung-Gu, Daegu, 700-412, South Korea
| | - Jae Sik Lee
- Department of Anatomy and Neurobiology, School of Medicine and Dentistry, Kyungpook National University, 188-1, 2-Ga, Samdeok-Dong, Jung-Gu, Daegu, 700-412, South Korea
| | - Sang Jin Ko
- Department of Anatomy and Neurobiology, School of Medicine and Dentistry, Kyungpook National University, 188-1, 2-Ga, Samdeok-Dong, Jung-Gu, Daegu, 700-412, South Korea
| | - Yi Sul Cho
- Department of Anatomy and Neurobiology, School of Medicine and Dentistry, Kyungpook National University, 188-1, 2-Ga, Samdeok-Dong, Jung-Gu, Daegu, 700-412, South Korea
| | - Jong-Cheol Rah
- Korea Brian Research Institute, 61 Cheomdan-ro, Dong-gu, Daegu, 701-300, South Korea
| | - Hee Jung Cho
- Department of Anatomy and Neurobiology, School of Medicine and Dentistry, Kyungpook National University, 188-1, 2-Ga, Samdeok-Dong, Jung-Gu, Daegu, 700-412, South Korea
| | - Mae Ja Park
- Department of Anatomy and Neurobiology, School of Medicine and 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 Medicine and Dentistry, Kyungpook National University, 188-1, 2-Ga, Samdeok-Dong, Jung-Gu, Daegu, 700-412, South Korea.
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Cho YS, Ryu CH, Won JH, Vang H, Oh SB, Ro JY, Bae YC. Rat odontoblasts may use glutamate to signal dentin injury. Neuroscience 2016; 335:54-63. [PMID: 27555550 DOI: 10.1016/j.neuroscience.2016.08.029] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 08/13/2016] [Accepted: 08/16/2016] [Indexed: 10/21/2022]
Abstract
Accumulating evidence indicates that odontoblasts act as sensor cells, capable of triggering action potentials in adjacent pulpal nociceptive axons, suggesting a paracrine signaling via a currently unknown mediator. Since glutamate can mediate signaling by non-neuronal cells, and peripheral axons may express glutamate receptors (GluR), we hypothesized that the expression of high levels of glutamate, and of sensory receptors in odontoblasts, combined with an expression of GluR in adjacent pulpal axons, is the morphological basis for odontoblastic sensory signaling. To test this hypothesis, we investigated the expression of glutamate, the thermo- and mechanosensitive ion channels transient receptor potential vanilloid 1 (TRPV1), transient receptor potential ankyrin 1 (TRPA1), and TWIK-1-related K+channel (TREK-1), and the glutamate receptor mGluR5, in a normal rat dental pulp, and following dentin injury. We also examined the glutamate release from odontoblast in cell culture. Odontoblasts were enriched with glutamate, at the level as high as in adjacent pulpal axons, and showed immunoreactivity for TRPV1, TRPA1, and TREK-1. Pulpal sensory axons adjacent to odontoblasts expressed mGluR5. Both the levels of glutamate in odontoblasts, and the expression of mGluR5 in nearby axons, were upregulated following dentin injury. The extracellular glutamate concentration was increased significantly after treating of odontoblast cell line with calcium permeable ionophore, suggesting glutamate release from odontoblasts. These findings lend morphological support to the hypothesis that odontoblasts contain glutamate as a potential neuroactive substance that may activate adjacent pulpal axons, and thus contribute to dental pain and hypersensitivity.
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Affiliation(s)
- Yi Sul Cho
- Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, Daegu 700-412, Republic of Korea
| | - Chang Hyun Ryu
- Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, Daegu 700-412, Republic of Korea
| | - Jong Hwa Won
- Pain Cognitive Function Research Center, Dental Research Institute of Neurobiology and Physiology, School of Dentistry, Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, Republic of Korea
| | - Hue Vang
- Pain Cognitive Function Research Center, Dental Research Institute of Neurobiology and Physiology, School of Dentistry, Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, Republic of Korea
| | - Seog Bae Oh
- Pain Cognitive Function Research Center, Dental Research Institute of Neurobiology and Physiology, School of Dentistry, Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, Republic of Korea
| | - Jin Young Ro
- Department of Neural and Pain Sciences, University of Maryland School of Dentistry, Baltimore, USA
| | - Yong Chul Bae
- Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, Daegu 700-412, Republic of Korea.
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Expression of glycine receptor alpha 3 in the rat trigeminal neurons and central boutons in the brainstem. Brain Struct Funct 2016; 221:4601-4613. [PMID: 26832918 DOI: 10.1007/s00429-016-1190-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Accepted: 01/14/2016] [Indexed: 10/22/2022]
Abstract
Increasing evidence shows that the homomeric glycine receptor is expressed in axon terminals and is involved in the presynaptic modulation of transmitter release. However, little is known about the expression of the glycine receptor, implicated in the presynaptic modulation of sensory transmission in the primary somatosensory neurons and their central boutons. To address this, we investigated the expression of glycine receptor subunit alpha 3 (GlyRα3) in the neurons in the trigeminal ganglion and axon terminals in the 1st relay nucleus of the brainstem by light- and electron-microscopic immunohistochemistry. Trigeminal primary sensory neurons were GlyRα3-immunopositive/gephyrin-immunonegative (indicating homomeric GlyR), whereas GlyRα3/gephyrin immunoreactivity (indicating heteromeric GlyR) was observed in dendrites. GlyRα3 immunoreactivity was also found in the central boutons of primary afferents but far from the presynaptic site and in dendrites at subsynaptic sites. Boutons expressing GlyRα3 contained small round vesicles, formed asymmetric synapses with dendrites and were immunoreactive for glutamate. These findings suggest that trigeminal primary afferent boutons receive presynaptic modulation via homomeric, extrasynaptic GlyRα3, and that different subtypes of GlyR may be involved in pre- and postsynaptic inhibition.
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Ohara H, Tachibana Y, Fujio T, Takeda-Ikeda R, Sato F, Oka A, Kato T, Ikenoue E, Yamashiro T, Yoshida A. Direct projection from the lateral habenula to the trigeminal mesencephalic nucleus in rats. Brain Res 2015; 1630:183-97. [PMID: 26592775 DOI: 10.1016/j.brainres.2015.11.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Revised: 09/29/2015] [Accepted: 11/08/2015] [Indexed: 12/30/2022]
Abstract
Trigeminal mesencephalic nucleus (Vmes) neurons are primary afferents conveying deep sensation from the masticatory muscle spindles or the periodontal mechanoreceptors, and are crucial for controlling jaw movements. Their cell bodies exist in the brain and receive descending commands from a variety of cortical and subcortical structures involved in limbic (emotional) systems. However, it remains unclear how the lateral habenula (LHb), a center of negative emotions (e.g., pain, stress and anxiety), can influence the control of jaw movements. To address this issue, we examined whether and how the LHb directly projects to the Vmes by means of neuronal tract tracing techniques in rats. After injections of a retrograde tracer Fluorogold in the rostral and caudal Vmes, a number of neurons were labeled in the lateral division of LHb (LHbl) bilaterally, whereas a few neurons were labeled in the medial division of LHb (LHbm) bilaterally. After injections of an anterograde tracer, biotinylated dextranamine (BDA) in the LHbl, a small number of labeled axons were distributed bilaterally in the rostral and caudal levels of Vmes, where some labeled axonal boutons contacted the cell body of rostral and caudal levels of Vmes neurons bilaterally. After the BDA injection into the LHbm, however, no axons were labeled bilaterally in the rostral and caudal levels of Vmes. Therefore, the present study for the first time demonstrated the direct projection from the LHbl to the Vmes and the detailed projection patterns, suggesting that jaw movements are modulated by negative emotions that are signaled by LHbl neurons.
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Affiliation(s)
- Haruka Ohara
- Department of Oral Anatomy and Neurobiology, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan; Department of Orthodontics and Dentofacial Orthopedics, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan
| | - Yoshihisa Tachibana
- Department of Oral Anatomy and Neurobiology, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan
| | - Takashi Fujio
- Department of Oral Anatomy and Neurobiology, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan
| | - Rieko Takeda-Ikeda
- Department of Oral Anatomy and Neurobiology, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan; Department of Orthodontics and Dentofacial Orthopedics, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan
| | - Fumihiko Sato
- Department of Oral Anatomy and Neurobiology, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan
| | - Ayaka Oka
- Department of Oral Anatomy and Neurobiology, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan; Department of Orthodontics and Dentofacial Orthopedics, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan
| | - Takafumi Kato
- Department of Oral Anatomy and Neurobiology, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan
| | - Etsuko Ikenoue
- Department of Oral Anatomy and Neurobiology, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan
| | - Takashi Yamashiro
- Department of Orthodontics and Dentofacial Orthopedics, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan
| | - Atsushi Yoshida
- Department of Oral Anatomy and Neurobiology, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan.
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Central connectivity of the chorda tympani afferent terminals in the rat rostral nucleus of the solitary tract. Brain Struct Funct 2014; 221:1125-37. [PMID: 25503820 DOI: 10.1007/s00429-014-0959-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Accepted: 12/06/2014] [Indexed: 10/24/2022]
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11
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Park SK, Kim JH, Yang ES, Ahn DK, Moon C, Bae YC. Ultrastructure and synaptic connectivity of main and accessory olfactory bulb efferent projections terminating in the rat anterior piriform cortex and medial amygdala. Brain Struct Funct 2013; 219:1603-13. [DOI: 10.1007/s00429-013-0588-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Accepted: 05/22/2013] [Indexed: 12/20/2022]
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