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Turner J, Couts K, Sheren J, Saichaemchan S, Ariyawutyakorn W, Avolio I, Cabral E, Glogowska M, Amato C, Robinson S, Hintzsche J, Applegate A, Seelenfreund E, Gonzalez R, Wells K, Bagby S, Tentler J, Tan AC, Wisell J, Varella-Garcia M, Robinson W. Kinase gene fusions in defined subsets of melanoma. Pigment Cell Melanoma Res 2017; 30:53-62. [PMID: 27864876 DOI: 10.1111/pcmr.12560] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 10/31/2016] [Indexed: 12/14/2022]
Abstract
Genomic rearrangements resulting in activating kinase fusions have been increasingly described in a number of cancers including malignant melanoma, but their frequency in specific melanoma subtypes has not been reported. We used break-apart fluorescence in situ hybridization (FISH) to identify genomic rearrangements in tissues from 59 patients with various types of malignant melanoma including acral lentiginous, mucosal, superficial spreading, and nodular. We identified four genomic rearrangements involving the genes BRAF, RET, and ROS1. Of these, three were confirmed by Immunohistochemistry (IHC) or sequencing and one was found to be an ARMC10-BRAF fusion that has not been previously reported in melanoma. These fusions occurred in different subtypes of melanoma but all in tumors lacking known driver mutations. Our data suggest gene fusions are more common than previously thought and should be further explored particularly in melanomas lacking known driver mutations.
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Affiliation(s)
- Jacqueline Turner
- Division of Medical Oncology, Department of Medicine, University of Colorado Denver, Aurora, CO, USA
| | - Kasey Couts
- Division of Medical Oncology, Department of Medicine, University of Colorado Denver, Aurora, CO, USA
| | - Jamie Sheren
- Division of Medical Oncology, Department of Medicine, University of Colorado Denver, Aurora, CO, USA
| | - Siriwimon Saichaemchan
- Division of Medical Oncology, Department of Medicine, University of Colorado Denver, Aurora, CO, USA
| | - Witthawat Ariyawutyakorn
- Division of Medical Oncology, Department of Medicine, University of Colorado Denver, Aurora, CO, USA
| | - Izabela Avolio
- Division of Medical Oncology, Department of Medicine, University of Colorado Denver, Aurora, CO, USA
| | - Ethan Cabral
- Division of Medical Oncology, Department of Medicine, University of Colorado Denver, Aurora, CO, USA
| | - Magdelena Glogowska
- Division of Medical Oncology, Department of Medicine, University of Colorado Denver, Aurora, CO, USA
| | - Carol Amato
- Division of Medical Oncology, Department of Medicine, University of Colorado Denver, Aurora, CO, USA
| | - Steven Robinson
- Division of Medical Oncology, Department of Medicine, University of Colorado Denver, Aurora, CO, USA
| | - Jennifer Hintzsche
- Division of Medical Oncology, Department of Medicine, University of Colorado Denver, Aurora, CO, USA
| | - Allison Applegate
- Division of Medical Oncology, Department of Medicine, University of Colorado Denver, Aurora, CO, USA
| | - Eric Seelenfreund
- Division of Medical Oncology, Department of Medicine, University of Colorado Denver, Aurora, CO, USA
| | - Rita Gonzalez
- Division of Medical Oncology, Department of Medicine, University of Colorado Denver, Aurora, CO, USA
| | - Keith Wells
- Division of Medical Oncology, Department of Medicine, University of Colorado Denver, Aurora, CO, USA
| | - Stacey Bagby
- Division of Medical Oncology, Department of Medicine, University of Colorado Denver, Aurora, CO, USA
| | - John Tentler
- Division of Medical Oncology, Department of Medicine, University of Colorado Denver, Aurora, CO, USA
| | - Aik-Choon Tan
- Division of Medical Oncology, Department of Medicine, University of Colorado Denver, Aurora, CO, USA
| | - Joshua Wisell
- Department of Pathology, University of Colorado Denver, Aurora, CO, USA
| | - Marileila Varella-Garcia
- Division of Medical Oncology, Department of Medicine, University of Colorado Denver, Aurora, CO, USA
| | - William Robinson
- Division of Medical Oncology, Department of Medicine, University of Colorado Denver, Aurora, CO, USA
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Holstein GR, Friedrich VLJ, Martinelli GP. Glutamate and GABA in Vestibulo-Sympathetic Pathway Neurons. Front Neuroanat 2016; 10:7. [PMID: 26903817 PMCID: PMC4744852 DOI: 10.3389/fnana.2016.00007] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 01/25/2016] [Indexed: 12/19/2022] Open
Abstract
The vestibulo-sympathetic reflex (VSR) actively modulates blood pressure during changes in posture. This reflex allows humans to stand up and quadrupeds to rear or climb without a precipitous decline in cerebral perfusion. The VSR pathway conveys signals from the vestibular end organs to the caudal vestibular nuclei. These cells, in turn, project to pre-sympathetic neurons in the rostral and caudal ventrolateral medulla (RVLM and CVLM, respectively). The present study assessed glutamate- and GABA-related immunofluorescence associated with central vestibular neurons of the VSR pathway in rats. Retrograde FluoroGold tract tracing was used to label vestibular neurons with projections to RVLM or CVLM, and sinusoidal galvanic vestibular stimulation (GVS) was employed to activate these pathways. Central vestibular neurons of the VSR were identified by co-localization of FluoroGold and cFos protein, which accumulates in some vestibular neurons following galvanic stimulation. Triple-label immunofluorescence was used to co-localize glutamate- or GABA- labeling in the identified VSR pathway neurons. Most activated projection neurons displayed intense glutamate immunofluorescence, suggestive of glutamatergic neurotransmission. To support this, anterograde tracer was injected into the caudal vestibular nuclei. Vestibular axons and terminals in RVLM and CVLM co-localized the anterograde tracer and vesicular glutamate transporter-2 signals. Other retrogradely-labeled cFos-positive neurons displayed intense GABA immunofluorescence. VSR pathway neurons of both phenotypes were present in the caudal medial and spinal vestibular nuclei, and projected to both RVLM and CVLM. As a group, however, triple-labeled vestibular cells with intense glutamate immunofluorescence were located more rostrally in the vestibular nuclei than the GABAergic neurons. Only the GABAergic VSR pathway neurons showed a target preference, projecting predominantly to CVLM. These data provide the first demonstration of two disparate chemoanatomic VSR pathways.
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Affiliation(s)
- Gay R. Holstein
- Department of Neurology, Icahn School of Medicine at Mount SinaiNew York, NY, USA
- Department of Neuroscience, Icahn School of Medicine at Mount SinaiNew York, NY, USA
- Department of Anatomy/Functional Morphology, Icahn School of Medicine at Mount SinaiNew York, NY, USA
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Differential Gene Expression Profile in the Rat Caudal Vestibular Nucleus is Associated with Individual Differences in Motion Sickness Susceptibility. PLoS One 2015; 10:e0124203. [PMID: 25910039 PMCID: PMC4409317 DOI: 10.1371/journal.pone.0124203] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Accepted: 03/10/2015] [Indexed: 12/15/2022] Open
Abstract
OBJECTIVE To identify differentially expressed genes associated with motion sickness (MS) susceptibility in the rat caudal vestibular nucleus. METHODS We identified MS susceptible (MSS) and insusceptible (inMSS) rats by quantifying rotation-induced MS symptoms: defecation and spontaneous locomotion activity. Microarray analysis was used to screen differentially expressed genes in the caudal vestibular nucleus (CVN) after rotation. Plasma stress hormones were identified by radioimmunoassay. Candidate genes were selected by bioinformatics analysis and the microarray results were verified by real-time quantitative-PCR (RT-qPCR) methods. By using Elvax implantation, receptor antagonists or recombinant adenovirus targeting the candidate genes were applied to the CVN to evaluate their contribution to MS susceptibility variability. Validity of gene expression manipulation was verified by RT-qPCR and western blot analysis. RESULTS A total of 304 transcripts were differentially expressed in the MSS group compared with the inMSS group. RT-qPCR analysis verified the expression pattern of candidate genes, including nicotinic cholinergic receptor (nAchR) α3 subunit, 5-hydroxytryptamine receptor 4 (5-HT4R), tachykinin neurokinin-1 (NK1R), γ-aminobutyric acid A receptor (GABAAR) α6 subunit, olfactory receptor 81 (Olr81) and homology 2 domain-containing transforming protein 1 (Shc1). In MSS animals, the nAchR antagonist mecamylamine significantly alleviated rotation-induced MS symptoms and the plasma β-endorphin response. The NK1R antagonist CP99994 and Olr81 knock-down were effective for the defecation response, while the 5-HT4R antagonist RS39604 and Shc1 over-expression showed no therapeutic effect. In inMSS animals, rotation-induced changes in spontaneous locomotion activity and the plasma β-endorphin level occurred in the presence of the GABAAR antagonist gabazine. CONCLUSION Our findings suggested that the variability of the CVN gene expression profile after motion stimulation might be a putative molecular basis for individual differences in MS susceptibility and provide information for the development of new therapeutic strategies for MSS individuals.
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Holstein GR, Friedrich VL, Martinelli GP. Projection neurons of the vestibulo-sympathetic reflex pathway. J Comp Neurol 2015; 522:2053-74. [PMID: 24323841 DOI: 10.1002/cne.23517] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2013] [Revised: 11/19/2013] [Accepted: 12/04/2013] [Indexed: 12/20/2022]
Abstract
Changes in head position and posture are detected by the vestibular system and are normally followed by rapid modifications in blood pressure. These compensatory adjustments, which allow humans to stand up without fainting, are mediated by integration of vestibular system pathways with blood pressure control centers in the ventrolateral medulla. Orthostatic hypotension can reflect altered activity of this neural circuitry. Vestibular sensory input to the vestibulo-sympathetic pathway terminates on cells in the vestibular nuclear complex, which in turn project to brainstem sites involved in the regulation of cardiovascular activity, including the rostral and caudal ventrolateral medullary regions (RVLM and CVLM, respectively). In the present study, sinusoidal galvanic vestibular stimulation was used to activate this pathway, and activated neurons were identified through detection of c-Fos protein. The retrograde tracer Fluoro-Gold was injected into the RVLM or CVLM of these animals, and immunofluorescence studies of vestibular neurons were conducted to visualize c-Fos protein and Fluoro-Gold concomitantly. We observed activated projection neurons of the vestibulo-sympathetic reflex pathway in the caudal half of the spinal, medial, and parvocellular medial vestibular nuclei. Approximately two-thirds of the cells were ipsilateral to Fluoro-Gold injection sites in both the RVLM and CVLM, and the remainder were contralateral. As a group, cells projecting to the RVLM were located slightly rostral to those with terminals in the CVLM. Individual activated projection neurons were multipolar, globular, or fusiform in shape. This study provides the first direct demonstration of the central vestibular neurons that mediate the vestibulo-sympathetic reflex.
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Affiliation(s)
- Gay R Holstein
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, New York, 10029; Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, New York, 10029
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Indo Y. Neurobiology of pain, interoception and emotional response: lessons from nerve growth factor-dependent neurons. Eur J Neurosci 2014; 39:375-91. [DOI: 10.1111/ejn.12448] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2013] [Revised: 10/31/2013] [Accepted: 11/09/2013] [Indexed: 01/01/2023]
Affiliation(s)
- Yasuhiro Indo
- Department of Pediatrics; Kumamoto University Hospital; Honjo 1-1-1, Chuou-ku Kumamoto 860-8556 Japan
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Li C, Han L, Ma CW, Lai SK, Lai CH, Shum DKY, Chan YS. Maturation profile of inferior olivary neurons expressing ionotropic glutamate receptors in rats: role in coding linear accelerations. Brain Struct Funct 2013; 218:833-50. [PMID: 22706760 PMCID: PMC3695329 DOI: 10.1007/s00429-012-0432-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2012] [Accepted: 05/17/2012] [Indexed: 11/30/2022]
Abstract
Using sinusoidal oscillations of linear acceleration along both the horizontal and vertical planes to stimulate otolith organs in the inner ear, we charted the postnatal time at which responsive neurons in the rat inferior olive (IO) first showed Fos expression, an indicator of neuronal recruitment into the otolith circuit. Neurons in subnucleus dorsomedial cell column (DMCC) were activated by vertical stimulation as early as P9 and by horizontal (interaural) stimulation as early as P11. By P13, neurons in the β subnucleus of IO (IOβ) became responsive to horizontal stimulation along the interaural and antero-posterior directions. By P21, neurons in the rostral IOβ became also responsive to vertical stimulation, but those in the caudal IOβ remained responsive only to horizontal stimulation. Nearly all functionally activated neurons in DMCC and IOβ were immunopositive for the NR1 subunit of the NMDA receptor and the GluR2/3 subunit of the AMPA receptor. In situ hybridization studies further indicated abundant mRNA signals of the glutamate receptor subunits by the end of the second postnatal week. This is reinforced by whole-cell patch-clamp data in which glutamate receptor-mediated miniature excitatory postsynaptic currents of rostral IOβ neurons showed postnatal increase in amplitude, reaching the adult level by P14. Further, these neurons exhibited subthreshold oscillations in membrane potential as from P14. Taken together, our results support that ionotropic glutamate receptors in the IO enable postnatal coding of gravity-related information and that the rostral IOβ is the only IO subnucleus that encodes spatial orientations in 3-D.
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Affiliation(s)
- Chuan Li
- Department of Physiology, LKS Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Hong Kong, People’s Republic of China
- Department of Biochemistry, LKS Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Hong Kong, People’s Republic of China
- Present Address: Department of Medical Science, Tung Wah College, Wyile Road, Kowloon Hong Kong, People’s Republic of China
| | - Lei Han
- Department of Physiology, LKS Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Hong Kong, People’s Republic of China
- Department of Biochemistry, LKS Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Hong Kong, People’s Republic of China
| | - Chun-Wai Ma
- Department of Physiology, LKS Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Hong Kong, People’s Republic of China
- Department of Biochemistry, LKS Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Hong Kong, People’s Republic of China
| | - Suk-King Lai
- Department of Physiology, LKS Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Hong Kong, People’s Republic of China
- Department of Biochemistry, LKS Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Hong Kong, People’s Republic of China
| | - Chun-Hong Lai
- Department of Physiology, LKS Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Hong Kong, People’s Republic of China
| | - Daisy Kwok Yan Shum
- Department of Biochemistry, LKS Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Hong Kong, People’s Republic of China
- Research Centre of Heart, Brain, Hormone and Healthy Aging, LKS Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Hong Kong, People’s Republic of China
| | - Ying-Shing Chan
- Department of Physiology, LKS Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Hong Kong, People’s Republic of China
- Research Centre of Heart, Brain, Hormone and Healthy Aging, LKS Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Hong Kong, People’s Republic of China
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Ma CW, Zhang FX, Lai CH, Lai SK, Yung KKL, Shum DKY, Chan YS. Postnatal expression of TrkB receptor in rat vestibular nuclear neurons responsive to horizontal and vertical linear accelerations. J Comp Neurol 2013; 521:612-25. [PMID: 22806574 DOI: 10.1002/cne.23193] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Revised: 10/17/2011] [Accepted: 07/09/2012] [Indexed: 11/05/2022]
Abstract
We examined the maturation expression profile of tyrosine kinase B (TrkB) receptor in rat vestibular nuclear neurons that were activated by sinusoidal linear acceleration along the horizontal or vertical axis. The otolithic origin of Fos expression in these neurons was confirmed with labyrinthectomized controls and normal controls, which showed only sporadically scattered Fos-labeled neurons in the vestibular nucleus. In P4-6 test rats, no Fos-labeled neurons were found in the vestibular nucleus, but the medial and spinal vestibular neurons showed weak immunoreactivity for TrkB. The intensity of TrkB immunoreactivity in vestibular nuclear neurons progressively increased in the second postnatal week but remained low in adults. From P7 onward, TrkB-expressing neurons responded to horizontal or vertical otolithic stimulation with Fos expression. The number of Fos-labeled vestibular nuclear neurons expressing TrkB increased with age, from 13-43% in P7 rats to 85-90% in adult rats. Our results therefore suggest that TrkB/neurotrophin signaling plays a dominant role in modulating vestibular nuclear neurons for the coding of gravity-related horizontal head movements and for the regulation of vestibular-related behavior during postnatal development.
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Affiliation(s)
- Chun-Wai Ma
- Department of Physiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, People's Republic of China
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Holstein GR, Friedrich Jr. VL, Martinelli GP, Ogorodnikov D, Yakushin SB, Cohen B. Fos expression in neurons of the rat vestibulo-autonomic pathway activated by sinusoidal galvanic vestibular stimulation. Front Neurol 2012; 3:4. [PMID: 22403566 PMCID: PMC3289126 DOI: 10.3389/fneur.2012.00004] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2011] [Accepted: 01/04/2012] [Indexed: 12/12/2022] Open
Abstract
The vestibular system sends projections to brainstem autonomic nuclei that modulate heart rate and blood pressure in response to changes in head and body position with regard to gravity. Consistent with this, binaural sinusoidally modulated galvanic vestibular stimulation (sGVS) in humans causes vasoconstriction in the legs, while low frequency (0.02-0.04 Hz) sGVS causes a rapid drop in heart rate and blood pressure in anesthetized rats. We have hypothesized that these responses occur through activation of vestibulo-sympathetic pathways. In the present study, c-Fos protein expression was examined in neurons of the vestibular nuclei and rostral ventrolateral medullary region (RVLM) that were activated by low frequency sGVS. We found c-Fos-labeled neurons in the spinal, medial, and superior vestibular nuclei (SpVN, MVN, and SVN, respectively) and the parasolitary nucleus. The highest density of c-Fos-positive vestibular nuclear neurons was observed in MVN, where immunolabeled cells were present throughout the rostro-caudal extent of the nucleus. c-Fos expression was concentrated in the parvocellular region and largely absent from magnocellular MVN. c-Fos-labeled cells were scattered throughout caudal SpVN, and the immunostained neurons in SVN were restricted to a discrete wedge-shaped area immediately lateral to the IVth ventricle. Immunofluorescence localization of c-Fos and glutamate revealed that approximately one third of the c-Fos-labeled vestibular neurons showed intense glutamate-like immunofluorescence, far in excess of the stain reflecting the metabolic pool of cytoplasmic glutamate. In the RVLM, which receives a direct projection from the vestibular nuclei and sends efferents to preganglionic sympathetic neurons in the spinal cord, we observed an approximately threefold increase in c-Fos labeling in the sGVS-activated rats. We conclude that localization of c-Fos protein following sGVS is a reliable marker for sGVS-activated neurons of the vestibulo-sympathetic pathway.
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Affiliation(s)
- Gay R. Holstein
- Department of Neurology, Mount Sinai School of MedicineNew York, NY, USA
- Department of Neuroscience, Mount Sinai School of MedicineNew York, NY, USA
- Department of Anatomy/Functional Morphology, Mount Sinai School of MedicineNew York, NY, USA
| | | | | | - Dmitri Ogorodnikov
- Department of Neurology, Mount Sinai School of MedicineNew York, NY, USA
| | - Sergei B. Yakushin
- Department of Neurology, Mount Sinai School of MedicineNew York, NY, USA
| | - Bernard Cohen
- Department of Neurology, Mount Sinai School of MedicineNew York, NY, USA
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Lai CH, Yiu CN, Lai SK, Ng KP, Yung KK, Shum DK, Chan YS. Maturation of canal-related brainstem neurons in the detection of horizontal angular acceleration in rats. J Comp Neurol 2010; 518:1742-63. [DOI: 10.1002/cne.22300] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Ma CW, Lai CH, Lai SK, Tse YC, Yung KK, Shum DK, Chan YS. Developmental distribution of vestibular nuclear neurons responsive to different speeds of horizontal translation. Brain Res 2010; 1326:62-7. [DOI: 10.1016/j.brainres.2010.02.032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2009] [Revised: 02/08/2010] [Accepted: 02/09/2010] [Indexed: 11/17/2022]
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Tse YC, Lai CH, Lai SK, Liu JX, Yung KKL, Shum DKY, Chan YS. Developmental expression of NMDA and AMPA receptor subunits in vestibular nuclear neurons that encode gravity-related horizontal orientations. J Comp Neurol 2008; 508:343-64. [PMID: 18335497 DOI: 10.1002/cne.21688] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
We examined the expression profile of subunits of ionotropic glutamate receptors [N-methyl-D-aspartate (NMDA) and alpha-amino-3-hydroxy-5-methyl-4-isoxazole-proprionate (AMPA)] during postnatal development of connectivity in the rat vestibular nucleus. Vestibular nuclear neurons were functionally activated by constant velocity off-vertical axis rotation, a strategy to stimulate otolith organs in the inner ear. These neurons indicated Fos expression as a result. By immunodetection for Fos, otolith-related neurons that expressed NMDA/AMPA receptor subunits were identified as early as P7, and these neurons were found to increase progressively up to adulthood. Although there was developmental invariance in the percentage of Fos-immunoreactive neurons expressing the NR1, NR2A, GluR1, or GluR2/3 subunits, those expressing the NR2B subunit decreased from P14 onward, and those expressing the GluR4 subunit decreased in adults. These double-immunohistochemical data were corroborated by combined immuno-/hybridization histochemical data obtained from Fos-immunoreactive neurons expressing NR2B mRNA or GluR4 mRNA. The staining of both NR2B and GluR4 in the cytoplasm of these neurons decreased upon maturation. The percentage of Fos-immunoreactive neurons expressing the other ionotropic glutamate receptor subunits (viz. NR1, NR2A, GluR1, and GluR2/3) remained relatively constant throughout postnatal maturation. Triple immunofluorescence further demonstrated coexpression of NR1 and NR2 subunits in Fos-immunoreactive neurons. Coexpression of NR1 subunit with each of the GluR subunits was also observed among the Fos-immunoreactive neurons. Taken together, the different expression profiles of ionotropic glutamate receptor subunits constitute the histological basis for glutamatergic neurotransmission in the maturation of central vestibular connectivity for the coding of gravity-related horizontal head movements.
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Affiliation(s)
- Yiu-Chung Tse
- Department of Physiology, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, People's Republic of China
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Cai YL, Ma WL, Li M, Guo JS, Li YQ, Wang LG, Wang WZ. Glutamatergic vestibular neurons express Fos after vestibular stimulation and project to the NTS and the PBN in rats. Neurosci Lett 2007; 417:132-7. [PMID: 17412503 DOI: 10.1016/j.neulet.2007.01.079] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2005] [Revised: 10/09/2006] [Accepted: 01/21/2007] [Indexed: 10/23/2022]
Abstract
In this study, retrograde tracing method combined with phosphate-activated glutaminase (PAG) and Fos immunofluorescence histochemistry was used to identify glutamatergic vestibular nucleus (VN) neurons receiving vestibular inputs and projecting to the nucleus of the solitary tract (NTS) and the parabrachial nucleus (PBN). Conscious animals were subjected to 120 min Ferris-wheel like rotation stimulation. Neuronal activation was assessed by Fos expression in the nucleus of VN neurons. After Fluoro-gold (FG) injection into the caudal NTS, approximately 48% FG-labeled VN neurons were immunoreactive for PAG, and about 14% PAG/FG double-labeled neurons co-existed with Fos. Following FG injection into the PBN, approximately 56% FG-labeled VN neurons were double-labeled with PAG, and about 12% of the PAG/FG double-labeled neurons also expressed Fos. Careful examination of the typology and distribution pattern of these PAG-immunoreactive neurons indicated that the vast majority of these neurons were glutamatergic rather than GABAergic. These results suggest that PAG-immunoreactive VN neurons might constitute excitatory glutamatergic VN-NTS and VN-PBN transmission pathways and these pathways might be involved in vestibulo-autonomic reflexes during vestibular stimulation.
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Affiliation(s)
- Yi-Ling Cai
- Department of Military Hygiene, Faculty of Naval Medicine, Second Military Medical University, Shanghai 200433, PR China.
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Lai SK, Lai CH, Yung KKL, Shum DKY, Chan YS. Maturation of otolith-related brainstem neurons in the detection of vertical linear acceleration in rats. Eur J Neurosci 2006; 23:2431-46. [PMID: 16706850 DOI: 10.1111/j.1460-9568.2006.04762.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
To investigate the critical maturation time of otolith-related neurons in processing vertical orientations, rats (postnatal day 4 to adults) were studied for functional activation of c-fos expression in brainstem neurons by immuno-/hybridization histochemistry. Conscious rats were subjected to sinusoidal linear acceleration along the vertical plane. Labyrinthectomized and/or stationary controls showed only sporadically scattered Fos-labeled neurons in the vestibular nuclei, confirming an otolithic origin of c-fos expression. Functionally activated Fos expression in neurons of the medial and spinal vestibular nuclei and group x were identifiable by P7 and those in group y by P9. A small number of Fos-labeled neurons characterized by small soma size were found in the ventral part of lateral vestibular nucleus by P9. Other vestibular-related areas such as prepostitus hypoglossal nucleus, gigantocellular reticular nucleus and locus coeruleus of normal experimental rats showed functionally activated c-fos expression at P7. Neurons in dorsal medial cell column and beta subnucleus of the inferior olive only showed functionally activated c-fos expression by the second postnatal week. These findings revealed a unique critical maturation time for each of the vestibular-related brainstem areas in the recognition of gravity-related vertical head orientations. By mapping the three-dimensional distribution of Fos-immunoreactive neurons, we found an even distribution of otolith-related neurons within the spinal vestibular nucleus in groups x and y but a clustered distribution in the middle-lateral-ventral part of the medial vestibular nucleus. Taken together, our findings reveal the developmental profile of neuronal subpopulations within the vertical otolith system, thereby providing an anatomical basis for postnatal coding of gravity-related vertical head movements.
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Affiliation(s)
- Suk-King Lai
- Department of Physiology, Faculty of Medicine, the University of Hong Kong, Sassoon Road, Hong Kong
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Chan YS, Lai CH, Shum DKY. Spatial coding capacity of central otolith neurons. Exp Brain Res 2006; 173:205-14. [PMID: 16683136 DOI: 10.1007/s00221-006-0491-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2006] [Accepted: 04/01/2006] [Indexed: 12/19/2022]
Abstract
This review focuses on recent approaches to unravel the capacity of otolith-related brainstem neurons for coding head orientations. In the first section, the spatiotemporal features of central vestibular neurons in response to natural otolithic stimulation are reviewed. Experiments that reveal convergent inputs from bilateral vestibular end organs bear important implications on the processing of spatiotemporal signals and integration of head orientational signals within central otolith neurons. Another section covers the maturation profile of central otolith neurons in the recognition of spatial information. Postnatal changes in the distribution pattern of neuronal subpopulations that subserve the horizontal and vertical otolith systems are highlighted. Lastly, the expression pattern of glutamate receptor subunits and neurotrophin receptors in otolith-related neurons within the vestibular nuclear complex are reviewed in relation to the potential roles of these receptors in the development of vestibular function.
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Affiliation(s)
- Ying-Shing Chan
- Department of Physiology, Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Hong Kong, People's Republic of China.
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15
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Zhang FX, Lai CH, Li JL, Shum DKY, Chan YS. Tyrosine kinase receptor immunoreactivity in trigeminal mesencephalic and motor neurons following transection of masseteric nerve of the rat. Neuroscience 2006; 139:921-30. [PMID: 16517086 DOI: 10.1016/j.neuroscience.2006.01.036] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2005] [Revised: 12/23/2005] [Accepted: 01/16/2006] [Indexed: 01/19/2023]
Abstract
Neurotrophins are known to promote survival after neural injury. To determine the relative importance of tyrosine kinase receptors on the survival of axotomized trigeminal nuclear neurons, we examined the temporal expression profile of tyrosine kinase A, tyrosine kinase B and tyrosine kinase C receptors in the mesencephalic trigeminal nucleus and the motor trigeminal nucleus following transection of the masseteric nerve in rats. Axotomized neurons in these nuclei were retrogradely identified with FluoroGold. We found increase in tyrosine kinase A-immunoreactive mesencephalic trigeminal nucleus neurons in the second week after axotomy but no change in the number of tyrosine kinase A-immunoreactive motor trigeminal nucleus neurons. There was no change in the number of tyrosine kinase B-immunoreactive mesencephalic trigeminal nucleus neurons but the significant increase of tyrosine kinase B-immunoreactive motor trigeminal nucleus neurons throughout the period of observation (3 weeks) peaked at approximately 1 week after axotomy. There was no alteration in the number of tyrosine kinase C-immunoreactive mesencephalic trigeminal nucleus neurons but significant increase in tyrosine kinase C-immunoreactive motor trigeminal nucleus neurons observable by 4 days post-axotomy was followed by decline to levels lower than the control in 2 weeks. Temporal changes in the expression of individual tyrosine kinase receptors in mesencephalic trigeminal nucleus and motor trigeminal nucleus neurons following transection of the masseteric nerve suggest differential contribution of tyrosine kinase-specific neurotrophins to the survival of these neurons after axotomy.
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Affiliation(s)
- F X Zhang
- Department of Anatomy and K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China
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16
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Chen LW, Tse YC, Li C, Guan ZL, Lai CH, Yung KKL, Shum DKY, Chan YS. Differential expression of NMDA and AMPA/KA receptor subunits in the inferior olive of postnatal rats. Brain Res 2006; 1067:103-14. [PMID: 16376317 DOI: 10.1016/j.brainres.2005.10.054] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2005] [Revised: 09/30/2005] [Accepted: 10/11/2005] [Indexed: 12/20/2022]
Abstract
We have employed immunohistochemistry to determine the expression patterns of receptor subunits of N-methyl-d-aspartate (NMDA-NR1 and NR2A/B) and alpha-amino-3-hydroxy-5-methyl-isoxazole-4-propionic acid/kainic acid (AMPA/KA-GluR1, GluR2, GluR2/3, GluR4, and GluR5/6/7) in the inferior olive of postnatal rats up to adulthood. Immunoreactivity for distinct receptor subunits was predominantly localized in the soma and dendrites of neurons. Semi-quantification showed that the overall immunoreactivity in the inferior olive of adults was intense for GluR1, moderate for NR1 and NR2A/B, and low for GluR2, GluR2/3, GluR4, and GluR5/6/7. At P7, GluR1 was restricted to the dorsomedial cell column, subnucleus beta, principal nucleus and ventrolateral protrusion while the other subunits were found in all subnuclei of the inferior olive. The immunoreactivities for all glutamate receptor subunits ranged from low to moderate. As the rats matured, the immunoreactivity of GluR4 decreased after the second postnatal week, while those of the other subunits showed a general trend of increase, reaching adult level during the third postnatal week. Double immunofluorescence revealed that all NR1-containing neurons exhibited NR2A/B immunoreactivity, indicating that native NMDA receptors comprise of hetero-oligomeric combinations of NR1 and NR2A/B. Furthermore, co-localization of NMDA and AMPA/KA receptor subunits was demonstrated in individual neurons of the inferior olive. All NR1-containing neurons exhibited GluR1 immunoreactivity, and all NR2A/B-containing neurons showed GluR5/6/7 immunoreactivity. Our data suggest that NMDA and AMPA/KA receptors are involved in glutamate-mediated neurotransmission, contributing to synaptic plasticity and reorganization of circuitry in the inferior olive during postnatal development.
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Affiliation(s)
- L-W Chen
- Department of Physiology, Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Hong Kong, PR China
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