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Yajima T, Sato T, Hosokawa H, Kondo T, Ichikawa H. Transient receptor potential melastatin-7 in the rat dorsal root ganglion. J Chem Neuroanat 2022; 125:102163. [PMID: 36122679 DOI: 10.1016/j.jchemneu.2022.102163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 09/08/2022] [Accepted: 09/15/2022] [Indexed: 11/30/2022]
Abstract
AIMS Transient receptor potential melastatin-7 (TRPM7) is a selective cation permeable channel which plays important roles in cellular and developmental biology such as cell proliferation, survival, differentiation and migration. This channel is also known to be necessary for transmitter release in the peripheral nervous system. In this study, immunohistochemistry for TRPM7 was conducted in the rat lumbar dorsal root ganglion (DRG). METHODS Triple immunofluorescence methods were used to demonstrate distribution of TRPM7 and its relationship to other TRP channels in the DRG. Retrograde tracing and double immunofluorescence methods were also performed to know peripheral targets of DRG neurons containing TRPM7 and TRP vanilloid 1 (TRPV1). In addition, transection of the sciatic nerve was conducted to demonstrate an effect of the nerve injury on TRPM7expression in the DRG. RESULTS TRPM7-immunoreactivity was expressed by 53.9% of sensory neurons in the 4th lumbar DRG. TRPM7-immunoreactive (-IR) DRG neurons mostly had small (<600 µm²) and medium-sized (600-1200 µm²) cell bodies. By triple and double immunofluorescence methods, approximately 70% of TRPM7-IR DRG neurons contained TRPV1-immunoreactivity. Although the number of DRG neurons co-expressing TRPM7 and TRPM8 was small in the DRG, almost all of TRPM8-IR DRG neurons co-expressed TRPM7-immunoreactivity. By combination of retrograde tracing method and immunohistochemistry, TRPM7 was expressed by half of DRG neurons innervating the plantar skin (61.9%) and gastrocnemius muscle (51.2%), and 79.6% of DRG neurons innervating the periosteum. Co-expression of TRPM7 and TRPV1 among periosteum DRG neurons (75.7%) was more abundant than among cutaneous (53.2%) and muscular (40.4%) DRG neurons. DRG neurons which co-expressed these ion channels in the periosteum had smaller cell bodies compared to the skin and muscle. In addition, the sciatic nerve transection decreased the number of TRPM7-IR neurons in the DRG (approximately 60% reduction). The RT-qPCR analysis also demonstrated reduction of TRPM7 mRNA in the injured DRG. CONCLUSION The present study suggests that TRPM7 is mainly located in small nociceptors in the DRG. The content of TRPM7 in DRG neurons is probably different among their peripheral targets. TRPM7 in DRG neurons may be able to respond to noxious stimulation from their peripheral tissues. The nerve injury can decrease the level of TRPM7 mRNA and protein in DRG neurons.
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Affiliation(s)
- Takehiro Yajima
- Division of Oral and Craniofacial Anatomy, Graduate School of Dentistry, Tohoku University, Sendai 980-8575, Japan
| | - Tadasu Sato
- Division of Oral and Craniofacial Anatomy, Graduate School of Dentistry, Tohoku University, Sendai 980-8575, Japan.
| | - Hiroshi Hosokawa
- Department of Intelligence Science and Technology, Graduate School of Informatics, Kyoto University, Kyoto 606-8501, Japan
| | - Teruyoshi Kondo
- Department of Animal Pharmaceutical Sciences, School of Pharmaceutical Sciences, Kyushu University of Health and Welfare, Nobeoka 882-8508, Japan
| | - Hiroyuki Ichikawa
- Division of Oral and Craniofacial Anatomy, Graduate School of Dentistry, Tohoku University, Sendai 980-8575, Japan
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A critical role for Piezo2 channels in the mechanotransduction of mouse proprioceptive neurons. Sci Rep 2016; 6:25923. [PMID: 27184818 PMCID: PMC4869095 DOI: 10.1038/srep25923] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 04/25/2016] [Indexed: 01/30/2023] Open
Abstract
Proprioceptors are responsible for the conscious sensation of limb position and movement, muscle tension or force, and balance. Recent evidence suggests that Piezo2 is a low threshold mechanosensory receptor in the peripheral nervous system, acting as a transducer for touch sensation and proprioception. Thus, we characterized proprioceptive neurons in the mesencephalic trigeminal nucleus that are involved in processing proprioceptive information from the face and oral cavity. This is a specific population of neurons that produce rapidly adapting mechanically-activated currents that are fully dependent on Piezo2. As such, we analyzed the deficits in balance and coordination caused by the selective deletion of the channel in proprioceptors (conditional knockout). The data clearly shows that Piezo2 fulfills a critical role in a defined homogeneous population of proprioceptor neurons that innervate the head muscles, demonstrating that this ion channel is essential for mammalian proprioceptive mechanotransduction.
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Mouton-Liger F, Sahún I, Collin T, Lopes Pereira P, Masini D, Thomas S, Paly E, Luilier S, Même S, Jouhault Q, Bennaï S, Beloeil JC, Bizot JC, Hérault Y, Dierssen M, Créau N. Developmental molecular and functional cerebellar alterations induced by PCP4/PEP19 overexpression: implications for Down syndrome. Neurobiol Dis 2013; 63:92-106. [PMID: 24291518 DOI: 10.1016/j.nbd.2013.11.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Revised: 11/05/2013] [Accepted: 11/19/2013] [Indexed: 11/28/2022] Open
Abstract
PCP4/PEP19 is a modulator of Ca(2+)-CaM signaling. In the brain, it is expressed in a very specific pattern in postmitotic neurons. In particular, Pcp4 is highly expressed in the Purkinje cell, the sole output neuron of the cerebellum. PCP4, located on human chromosome 21, is present in three copies in individuals with Down syndrome (DS). In a previous study using a transgenic mouse model (TgPCP4) to evaluate the consequences of 3 copies of this gene, we found that PCP4 overexpression induces precocious neuronal differentiation during mouse embryogenesis. Here, we report combined analyses of the cerebellum at postnatal stages (P14 and adult) in which we identified age-related molecular, electrophysiological, and behavioral alterations in the TgPCP4 mouse. While Pcp4 overexpression at P14 induces an earlier neuronal maturation, at adult stage it induces increase in cerebellar CaMK2alpha and in cerebellar LTD, as well as learning impairments. We therefore propose that PCP4 contributes significantly to the development of Down syndrome phenotypes through molecular and functional changes.
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Affiliation(s)
- François Mouton-Liger
- Univ Paris Diderot, Sorbonne Paris Cité, Unité de Biologie Fonctionnelle et Adaptative, EAC4413 CNRS, Paris, France
| | - Ignasi Sahún
- Cellular and Systems Biology, Systems Biology Programme, Center for Genomic Regulation (CRG); Universitat Pompeu Fabra (UPF); Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER): Dr. Aiguader, 88, 08003 Barcelona, Spain
| | - Thibault Collin
- CNRS UMR8118, Brain Physiology Laboratory, Universite Paris-Descartes, Centre universitaire des Saints-Pères, 45 Rue des Saints-Pères, 75270 Paris Cedex 06, France
| | - Patricia Lopes Pereira
- Transgenese et Archivage Animaux Modèles, TAAM, CNRS, UPS44, 3B rue de la Férollerie, 45071 Orléans, France
| | - Debora Masini
- Cellular and Systems Biology, Systems Biology Programme, Center for Genomic Regulation (CRG); Universitat Pompeu Fabra (UPF); Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER): Dr. Aiguader, 88, 08003 Barcelona, Spain
| | - Sophie Thomas
- Univ Paris Diderot, Sorbonne Paris Cité, Unité de Biologie Fonctionnelle et Adaptative, EAC4413 CNRS, Paris, France
| | - Evelyne Paly
- Univ Paris Diderot, Sorbonne Paris Cité, Unité de Biologie Fonctionnelle et Adaptative, EAC4413 CNRS, Paris, France
| | - Sabrina Luilier
- Key-Obs SAS, 13 avenue Buffon, 45071 Orléans Cedex 2, France
| | - Sandra Même
- Centre de Biophysique Moléculaire, CNRS UPR 4301, Orléans, France
| | - Quentin Jouhault
- Univ Paris Diderot, Sorbonne Paris Cité, Unité de Biologie Fonctionnelle et Adaptative, EAC4413 CNRS, Paris, France
| | - Soumia Bennaï
- Univ Paris Diderot, Sorbonne Paris Cité, Unité de Biologie Fonctionnelle et Adaptative, EAC4413 CNRS, Paris, France
| | | | | | - Yann Hérault
- Transgenese et Archivage Animaux Modèles, TAAM, CNRS, UPS44, 3B rue de la Férollerie, 45071 Orléans, France; Institut Clinique de la Souris, ICS, 1 rue Laurent Fries, 67404 Illkirch, France; Institut de Génétique Biologie Moléculaire et Cellulaire, Translational medicine and Neuroscience program, IGBMC, CNRS, INSERM, Université de Strasbourg, UMR7104, UMR964, 1 rue Laurent Fries, 67404 Illkirch, France
| | - Mara Dierssen
- Cellular and Systems Biology, Systems Biology Programme, Center for Genomic Regulation (CRG); Universitat Pompeu Fabra (UPF); Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER): Dr. Aiguader, 88, 08003 Barcelona, Spain
| | - Nicole Créau
- Univ Paris Diderot, Sorbonne Paris Cité, Unité de Biologie Fonctionnelle et Adaptative, EAC4413 CNRS, Paris, France.
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Patterson-Buckendahl P, Sowinska A, Yee S, Patel D, Pagkalinawan S, Shahid M, Shah A, Franz C, Benjamin DE, Pohorecky LA. Decreased sensory responses in osteocalcin null mutant mice imply neuropeptide function. Cell Mol Neurobiol 2012; 32:879-89. [PMID: 22350212 DOI: 10.1007/s10571-012-9810-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Accepted: 01/23/2012] [Indexed: 11/25/2022]
Abstract
Osteocalcin, the most abundant member of the family of extracellular mineral binding gamma-carboxyglutamic acid proteins is synthesized primarily by osteoblasts. Its affinity for calcium ions is believed to limit bone mineralization. Several of the numerous hormones that regulate synthesis of osteocalcin, including glucocorticoids and parathyroid hormone, are also affected by stressful stimuli that require energy for an appropriate response. Based on our observations of OC responding to stressful sensory stimuli, the expression of OC in mouse and rat sensory ganglia was confirmed. It was thus hypothesized that the behavioral responses of the OC knockout mouse to stressful sensory stimuli would be abnormal. To test this hypothesis, behaviors related to sensory aspects of the stress response were quantified in nine groups of mice, aged 4-14 months, comparing knockout with their wild-type counterparts in six distinctly different behavioral tests. Resulting data indicated the following statistically significant differences: open field grooming frequency following saline injection, wild-type > knockout; paw stimulation with Von Frey fibers, knockout < wild-type; balance beam, knockout mobility < WT; thermal sensitivity to heat (tail flick), knockout < wild-type; and cold, knockout < wild-type. Insignificant differences in hanging wire test indicate that these responses are unrelated to reduced muscle strength. Each of these disparate environmental stimuli provided data indicating alterations of responses in knockout mice that suggest participation of osteocalcin in transmission of information about those sensory stimuli.
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Development of primary sensory neurons in the trigeminal nervous system; dependency on neurotrophins and other substances. JAPANESE DENTAL SCIENCE REVIEW 2012. [DOI: 10.1016/j.jdsr.2011.10.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Suzuki T, Sato T, Sasaki R, Ichikawa H. Peptide 19-containing neurons in the medullary dorsal horn, subnuclei interpolaris and oralis, and nucleus principalis of the rat. Ann Anat 2011; 194:321-8. [PMID: 22197496 DOI: 10.1016/j.aanat.2011.11.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2011] [Revised: 11/01/2011] [Accepted: 11/01/2011] [Indexed: 11/17/2022]
Abstract
Peptide 19 (PEP 19) is a 7.6 kDa polypeptide which can bind to calmodulin and inhibit calcium-calmodulin signaling. In this study, PEP 19-immunoreactivity (ir) was examined in the rat trigeminal sensory nuclei. Numerous PEP 19-immunoreactive (ir) neurons were detected in the medullary dorsal horn (MDH) and rostral parts of the trigeminal sensory nuclei (subnuclei interpolaris and oralis, and nucleus principalis). The mean numbers ± S.D. per section of PEP 19-ir neurons were 104.2 ± 30.4 in the MDH, 137.8 ± 39.5 in the subnucleus interpolaris, 129.2 ± 46.9 in the subnucleus oralis and 157.2 ± 34.1 in the nucleus principalis. In the MDH, small to medium-sized PEP 19-ir neurons were abundant within superficial laminae. PEP 19-ir neurons with various cell body sizes were also distributed in the rostral parts of the trigeminal sensory nuclei. A double immunofluorescence analysis also demonstrated that many PEP 19-ir neurons co-expressed parvalbumin (PV)-ir in the MDH (9.0%), subnucleus oralis (7.7%) and nucleus principalis (19.7%). In the subnucleus interpolaris, such neurons were relatively rare (1.7%). PEP 19-ir neurons were mostly devoid of calbindin D-28k. In addition, a retrograde tracing method revealed that a substantial number of PEP 19-ir neurons projected to the thalamus. PV-ir was common in thalamus-projecting PEP 19-ir neurons. These findings suggest that PEP 19-ir neurons in the MDH may have a function in modulation of nociceptive and thermo-receptive signaling. It is also likely that PEP 19-ir neurons in rostral parts of the trigeminal sensory nuclei are related to transduction of mechano-receptive information from facial regions to the thalamus.
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Affiliation(s)
- Toshihiko Suzuki
- Division of Oral and Craniofacial Anatomy, Graduate School of Dentistry, Tohoku University, Sendai, Japan
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7
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Mouton-Liger F, Thomas S, Rattenbach R, Magnol L, Larigaldie V, Ledru A, Herault Y, Verney C, Créau N. PCP4 (PEP19) overexpression induces premature neuronal differentiation associated with Ca(2+) /calmodulin-dependent kinase II-δ activation in mouse models of Down syndrome. J Comp Neurol 2011; 519:2779-802. [PMID: 21491429 DOI: 10.1002/cne.22651] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Pcp4/pep19 is a modulator of Ca(2+) -CaM, a key molecule for calcium signaling, expressed in postmitotic neuroectoderm cells during mouse embryogenesis. The PCP4 gene is located on human chromosome 21 and is present in three copies in Down syndrome (DS). To evaluate the consequences of three copies of this gene on the development of these cells in the nervous system, we constructed a transgenic (TgPCP4) mouse model, with one copy of human PCP4, and investigated the effects in this model and in the Ts1Cje, a mouse model of DS. During embryogenesis, we analyzed 1) the level of pcp4 transcript and protein in the two models; 2) the extent of colabeling for markers of neuronal differentiation (βIII-tubulin, Map2c, calbindin, and calretinin) and pcp4 by immunofluorescence analysis and overall protein levels of these markers by Western blotting; and 3) the rate of activation of CaMKII, a Ca(2+) -CaM target, to evaluate the impact of pcp4 overexpression on the Ca(2+) -CaM signaling pathway. We showed that three copies of the pcp4 gene induced the overexpression of transcripts and proteins during embryogenesis. Pcp4 overexpression 1) induced precocious neuronal differentiation, as shown by the distribution and levels of early neuronal markers; and 2) was associated with an increase in CaMKIIδ activation, confirming involvement in neuronal differentiation in vivo via a Pcp4-Ca(2+) -CaM pathway. TgPCP4 and Ts1Cje mice developed similar modifications, demonstrating that these mechanisms may account for abnormal neuronal development in DS.
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Affiliation(s)
- François Mouton-Liger
- Functional Adaptive Biology (BFA), Centre National de la Recherche Scientifique (CNRS) EAC4413, Université Paris Diderot-Paris7, 75205 Paris Cedex 13, France
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8
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Drebrin (developmentally regulated brain protein) is associated with axo-somatic synapses and neuronal gap junctions in rat mesencephalic trigeminal nucleus. Neurosci Lett 2009; 461:95-9. [DOI: 10.1016/j.neulet.2009.06.027] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2009] [Revised: 06/06/2009] [Accepted: 06/12/2009] [Indexed: 11/21/2022]
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9
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Peptide 19 in the rat superior cervical ganglion. Neuroscience 2009; 161:86-94. [PMID: 19303431 DOI: 10.1016/j.neuroscience.2009.03.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2009] [Revised: 03/05/2009] [Accepted: 03/09/2009] [Indexed: 11/23/2022]
Abstract
Peptide 19 is a 7.6 kDa polypeptide which can bind to calmodulin and inhibit calcium-calmodulin signaling. In this study, peptide 19-immunoreactivity was examined in the rat superior cervical ganglion. In the ganglion, 54.8% of postganglionic sympathetic neuron profiles were immunoreactive for peptide 19. These neuron profiles were small- to medium-sized and measured 87-845 microm(2) (mean+/-SD = 343+/-111 microm(2)). Double immunofluorescence method revealed that 99.9% of peptide 19-containing neurons had neuropeptide Y in the superior cervical ganglion. Retrograde neuronal tracing and immunohistochemical studies also demonstrated that peptide 19 was common in postganglionic sympathetic neurons which innervated the facial skin and masseter but not the submandibular gland; 55.6% and 75.2% of cutaneous and muscular neuron profiles, respectively, contained peptide 19. Only 9.8% of glandular neurons were immunoreactive for peptide 19. These findings indicate that the content of peptide 19 in superior cervical ganglion neurons depends on their cell sizes and peripheral projections. On the other hand, colchicine injection into the superior cervical ganglion decreased the number of peptide 19-positive neurons (30.7%) compared to saline injection (53.3%). In contrast, the treatment induced nicotine adenine dinucleotide phosphate diaphorase activity in 12.7% of postganglionic sympathetic neurons. Double stain demonstrated that 56.3% of nicotine adenine dinucleotide phosphate diaphorase-positive neurons co-expressed peptide 19. These findings indicate that colchicine treatment causes decrease of peptide 19 expression and increase of nitric oxide synthase activity.
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Ichikawa H, Terayama R, Yamaai T, De Repentigny Y, Kothary R, Sugimoto T. The number of nociceptors in the trigeminal ganglion but not proprioceptors in the mesencephalic trigeminal tract nucleus is reduced in dystonin deficient dystonia musculorum mice. Brain Res 2008; 1226:33-8. [DOI: 10.1016/j.brainres.2008.05.063] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2008] [Revised: 05/23/2008] [Accepted: 05/27/2008] [Indexed: 12/31/2022]
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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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Ichikawa H, Jin HW, Terayama S, Yamaai T, Matsuo S, Sugimoto T. The reduction of proprioceptors in the mesencephalic trigeminal tract nucleus after neonatal masseteric nerve transection; effect of brain-derived neurotrophic factor. Brain Res 2007; 1153:98-102. [PMID: 17466283 DOI: 10.1016/j.brainres.2007.03.060] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2006] [Revised: 03/07/2007] [Accepted: 03/21/2007] [Indexed: 02/04/2023]
Abstract
The effect of neonatal masseteric nerve transection on primary proprioceptors was examined in the mesencephalic trigeminal tract nucleus (Mes5) of the rat. At 72 h to 21 days after the injury, the number of Mes5 neurons decreased on the side ipsilateral to the transection. The means+/-SD of percentage proportion of ipsilateral/contralateral neurons at 72 h and 21 days were 69.9+/-7.5% and 58.2+/-14.6%, respectively. The application of brain-derived neurotrophic factor to the proximal stump of the masseteric nerve delayed the loss of Mes5 neurons at 72 h after the injury; the mean numbers+/-SD of ipsilateral and contralateral Mes5 neurons in injured animals with BDNF application was 553.6+/-61.9 and 558.4+/-55.3, respectively. Saline application had no effect on the injury-induced loss of Mes5 neurons; i.e., the mean numbers+/-SD of ipsilateral and contralateral Mes5 neurons were 367.3+/-72.5 and 543+/-33.5, respectively. These findings indicate that trigeminal primary proprioceptors are sensitive to the neonatal injury. The survival of proprioceptors during early postnatal period is probably dependent upon brain-derived neurotrophic factor in the trigeminal nervous system.
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Affiliation(s)
- H Ichikawa
- Department of Oral Function and Anatomy, Okayama University Graduate School of Medicine and Dentistry, 2-5-1 Shikata-cho, Okayama 700-8525, Japan.
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Dickerson JB, Morgan MA, Mishra A, Slaughter CA, Morgan JI, Zheng J. The influence of phosphorylation on the activity and structure of the neuronal IQ motif protein, PEP-19. Brain Res 2006; 1092:16-27. [PMID: 16740252 DOI: 10.1016/j.brainres.2006.03.048] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2006] [Revised: 03/02/2006] [Accepted: 03/06/2006] [Indexed: 11/24/2022]
Abstract
PEP-19 is a 7.6 kDa neuronally expressed polypeptide that contains a single calmodulin-binding IQ motif. The calmodulin-binding activity of several neuronal IQ motif proteins is regulated by phosphorylation of a conserved serine. We propose that the serine residue within the IQ motif of PEP-19 is phosphorylated, and that phosphorylation modifies the activity of PEP-19. Camstatin, a functionally active 25-residue fragment of PEP-19's IQ motif, binds calmodulin and inhibits neuronal nitric oxide synthase. A truncated camstatin-in which the IQ motif serine is the only phosphorylatable residue-was screened against 42 different kinases. Truncated camstatin is selectively phosphorylated by four isoforms of protein kinase C. Furthermore, treatment of full-length PEP-19 with PKCgamma catalyzes phosphorylation of the same serine residue. Fluorescent anisotropy shows that phosphorylation of camstatin inhibits its binding to calmodulin. NMR solution structures indicate that both camstatin and phospho-camstatin exist in similar dynamic turn-like conformations. This suggests that camstatin's greater affinity for calmodulin is due not to a change in the conformation of the phospho-peptide, but rather, to a disruption of hydrophobic interactions between phospho-camstatin and calmodulin caused by the presence of the hydrophilic phosphate group. The H(alpha) chemical shifts and the circular dichroism spectra of the camstatins are consistent with those of "nascent helices". We submit that PEP-19 is a PKC substrate, and that the phosphorylation state of PEP-19 may play a role in the modulation of calmodulin-dependent signaling.
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Affiliation(s)
- J Bradley Dickerson
- Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
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Sköld K, Svensson M, Nilsson A, Zhang X, Nydahl K, Caprioli RM, Svenningsson P, Andrén PE. Decreased Striatal Levels of PEP-19 Following MPTP Lesion in the Mouse. J Proteome Res 2006; 5:262-9. [PMID: 16457591 DOI: 10.1021/pr050281f] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
PEP-19 is a neuronal calmodulin-binding protein, and as such, a putative modulator of calcium regulated processes. In the present study, we used proteomics technology approaches such as peptidomics and imaging MALDI mass spectrometry, as well as traditional techniques (immunoblotting and in situ hybridization) to identify PEP-19 and, specifically, to measure PEP-19 mRNA and protein levels in an animal model of Parkinson's disease. 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) administration in mice resulted in a significant decrease in striatal PEP-19 mRNA. Capillary nano-flow liquid chromatography electrospray mass spectrometry analysis of striatal tissue revealed a significant decrease of the PEP-19 protein level. Moreover, imaging MALDI mass spectrometry also showed that PEP-19 protein was predominantly localized to the striatum of the brain tissue cross sections. After MPTP administration, PEP-19 levels were significantly reduced by 30%. We conclude that PEP-19 mRNA and protein expression are decreased in the striatum of a common animal model of Parkinson's disease. Further studies are needed to show the specific involvement of PEP-19 in the neurodegeneration seen in MPTP lesioned animals. Finally, this study has shown that the combination of traditional molecular biology techniques with novel, highly specific and sensitive mass spectrometry methods is advantageous in characterizing molecular events of many diseases, including Parkinson's disease.
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Affiliation(s)
- Karl Sköld
- Laboratory for Biological and Medical Mass Spectrometry, Uppsala University, Box 583 Biomedical Centre, SE-75123 Uppsala, Sweden
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Ichikawa H, Qiu F, Xiang M, Sugimoto T. Brn-3a is required for the generation of proprioceptors in the mesencephalic trigeminal tract nucleus. Brain Res 2005; 1053:203-6. [PMID: 16040009 DOI: 10.1016/j.brainres.2005.06.026] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2005] [Revised: 06/07/2005] [Accepted: 06/10/2005] [Indexed: 10/25/2022]
Abstract
The distribution of motor and proprioceptive neurons was investigated in the trigeminal nervous system of wild-type and Brn-3a knockout mice at embryonic day 18.5 and postnatal day 0. We found that the trigeminal motor nucleus (Mo5) contained abundant motoneurons in wild-type (mean number +/- SD per section = 128 +/- 22, range = 93-167) and knockout (mean number +/- SD per section = 121 +/- 23, range = 75-158) mice and that the cell size of Mo5 neurons was similar between these mice (wild-type, mean +/- SD = 165 +/- 59 microm2, range = 65-326 microm2; knockout, mean +/- SD = 167 +/- 59 microm2, range = 71-327 microm2). Mo5 neurons were immunoreactive for calcitonin gene-related peptide and such immunoreactive neurons were abundant in both wild-type and mutant mice. In the mesencephalic tract nucleus (Mes5) of wild-type mice, many proprioceptors (mean number +/- SD per section = 56 +/- 19, range = 27-85) that contained parvalbumin immunoreactivity were also observed. In knockout mice, however, Mes5 neurons could not be detected. The area of brainstems which normally contained the Mes5 was devoid of parvalbumin-immunoreactive proprioceptors. The present study suggests that Brn-3a is required for the development of proprioceptors but not motoneurons in the trigeminal nervous system.
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Affiliation(s)
- H Ichikawa
- Department of Oral Function and Anatomy, Okayama University Graduate School of Medicine and Dentistry, 2-5-1 Shikata-cho, Okayama 700-8525, Japan.
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Ichikawa H, Sugimoto T. Peptide 19 in the rat vagal and glossopharyngeal sensory ganglia. Brain Res 2005; 1038:107-12. [PMID: 15748879 DOI: 10.1016/j.brainres.2005.01.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2004] [Revised: 12/20/2004] [Accepted: 01/01/2005] [Indexed: 01/01/2023]
Abstract
Peptide 19 (PEP 19) is a 7.6-kDa polypeptide which binds to calmodulin and inhibits calcium-calmodulin signaling. In this study, PEP 19-immunoreactivity (PEP 19-IR) was examined in the rat vagal and glossopharyngeal sensory ganglia. Twenty-nine percent, 59%, and 41% of sensory neurons contained PEP 19-IR in the jugular, petrosal, and nodose ganglia, respectively. These neurons were of various sizes (jugular, mean +/- SD = 635.8 +/- 392.6 microm2, range = 105.9-1695.9 microm2; petrosal, mean +/- SD = 370.9 +/- 228.5 microm2, range = 57.7-1662.7 microm2; nodose, mean +/- SD = 380.5 +/- 157 microm2, range = 87.5-950.4 microm2) and scattered throughout these ganglia. Double immunofluorescence method revealed that PEP 19-IR neurons which had parvalbumin-IR were rare in the ganglia (jugular, 4%; petrosal, 10%; nodose, 8%). PEP 19-IR neurons which contained calbindin D-28k were abundant in the petrosal (20%) and nodose (22%) ganglia but not in the jugular ganglion (8%). Retrograde tracing method indicated that many PEP 19-IR neurons projected to the circumvallate papilla and soft palate. In the soft palate, taste buds were innervated by PEP 19-IR nerve fibers. The present study suggests that PEP 19-IR neurons include chemoreceptors in the vagal and glossopharyngeal sensory ganglia.
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Affiliation(s)
- H Ichikawa
- Department of Oral Function and Anatomy and Biodental Research Center, Okayama University Graduate School of Medicine and Dentistry, 2-5-1 Shikata-cho, Okayama 700-8525, Japan.
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Imamura S, Adams JC. Selective gentamicin uptake by cytochemical subpopulations of guinea-pig geniculate ganglion cells. Neuroscience 2005; 131:125-33. [PMID: 15680697 DOI: 10.1016/j.neuroscience.2004.11.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/04/2004] [Indexed: 11/29/2022]
Abstract
Cytochemical subpopulations of geniculate ganglion (GG) cells were identified in guinea-pigs using immunohistochemistry and selective gentamicin accumulation. Two subpopulations of GG cells were evident based upon their location and immunoreactivity for peptide 19 (PEP 19), for plasma membrane Ca2+-ATPase (PMCA-ATPase), and for neurofilament proteins. Cells within the posterior part of GG were positive for PEP 19 and PMCA-ATPase, but not for 68 kD or 160 kD neurofilament proteins. Cells within the anterior part showed complementary staining properties. Cells within these populations showed differences in accumulation of gentamicin, depending upon the administration route. Cells within the posterior part showed avid accumulation of gentamicin when animals received the drug systemically. When the drug was administered directly into the middle ear, cells within the anterior part showed avid gentamicin accumulation. Immunostaining for gentamicin in both cell populations was much more extreme and remained so for longer post-administration times when compared with spiral ganglion and vestibular ganglion cells. The results suggest that cells in the anterior part of GG have little exposure to gentamicin in the serum and that perhaps they innervate the middle ear mucosa or they absorb the drug through their axons within the middle ear. In contrast, cells in the posterior part of GG have greater access to systemically administered gentamicin either directly or via their axon terminals.
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Affiliation(s)
- S Imamura
- Department of Otorhinolaryngology, Yamanashi University, 1110 Shimokato, Tamaho, Yamanashi, Japan 409-3898.
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Ichikawa H, Jin HW, Fujita M, Nagaoka N, Sugimoto T. Osteocalcin-immunoreactive neurons in the vagal and glossopharyngeal sensory ganglia of the rat. Brain Res 2005; 1031:129-33. [PMID: 15621021 DOI: 10.1016/j.brainres.2004.10.011] [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] [Accepted: 10/12/2004] [Indexed: 11/20/2022]
Abstract
Immunohistochemistry for osteocalcin (OC) was performed on the rat vagal and glossopharyngeal sensory ganglia. OC-immunoreactive (IR) neurons were detected in the jugular (10%), petrosal (11%) and nodose ganglia (6%). The cell size analysis demonstrated that OC-IR neurons were predominantly small to medium-sized in the jugular ganglion (mean+/-S.D.=356.3+/-192.2 microm(2), range=86.5-831.5 microm(2)). On the other hand, such neurons were medium-sized to large in the petrosal (mean+/-S.D.=725.6+/-280.7 microm(2), range=124.7-1540.4 microm(2)) and nodose ganglia (mean+/-S.D.=857.5+/-330.2 microm(2), range=367.1-1608.0 microm(2)). In the circumvallate papilla, OC-IR nerve fibers were located in the vicinity of taste buds. Some taste bud cells were also immunoreactive for the calcium-binding protein (CaBP). In the carotid body, however, OC-IR nerve fibers could not be detected. Retrograde tracing with fluorogold revealed that OC-IR nerve fibers in the circumvallate papilla mainly originated from the petrosal ganglion. These findings may suggest that OC-IR petrosal neurons have chemoreceptive function in the tongue.
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Affiliation(s)
- H Ichikawa
- Department of Oral Function and Anatomy, Okayama University Graduate School of Medicine and Dentistry, 2-5-1 Shikata-cho, Okayama 700-8525, Japan.
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Abstract
Immunohistochemistry detected calcium-binding proteins (CaBPs) in corpuscular and Merkel nerve endings of the rat vibrissa. CaBP-immunoreactive (ir) corpuscular endings were divided into two types: ramified and unramified endings. Ramified endings were subdivided into reticular and Ruffini endings. Unramified endings were identical to longitudinal lanceolate endings which have been described previously. Reticular and unramified endings as well as Merkel endings co-expressed neurocalcin (NC)- and parvalbumin (PV)-immunoreactivity (ir). However, such endings were devoid of peptide 19 (PEP19)-ir. PV-ir Ruffini endings were immunoreactive for PEP19 but not NC. The retrograde tracing method revealed that 34, 21 and 18% of trigeminal neurons which project to the infraorbital nerve exhibited NC-, PEP19- and PV-ir, respectively. In addition, 73 and 36% of the PV-ir neurons showed NC- and PEP19-ir, respectively. The content and co-expression of CaBPs in vibrissal low-threshold mechanoreceptors may depend on their terminal morphology.
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Affiliation(s)
- H Ichikawa
- Department of Oral Function and Anatomy, and Biodental Research Center, Okayama University Graduate School of Medicine and Dentistry, 2-5-1 Shikata-cho, Japan.
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Lazarov NE. Comparative analysis of the chemical neuroanatomy of the mammalian trigeminal ganglion and mesencephalic trigeminal nucleus. Prog Neurobiol 2002; 66:19-59. [PMID: 11897404 DOI: 10.1016/s0301-0082(01)00021-1] [Citation(s) in RCA: 189] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
A characteristic peculiarity of the trigeminal sensory system is the presence of two distinct populations of primary afferent neurons. Most of their cell bodies are located in the trigeminal ganglion (TG) but part of them lie in the mesencephalic trigeminal nucleus (MTN). This review compares the neurochemical content of central versus peripheral trigeminal primary afferent neurons. In the TG, two subpopulations of primary sensory neurons, containing immunoreactive (IR) material, are identified: a number of glutamate (Glu)-, substance P (SP)-, neurokinin A (NKA)-, calcitonin gene-related peptide (CGRP)-, cholecystokinin (CCK)-, somatostatin (SOM)-, vasoactive intestinal polypeptide (VIP)- and galanin (GAL)-IR ganglion cells with small and medium-sized somata, and relatively less numerous larger-sized neuropeptide Y (NPY)- and peptide 19 (PEP 19)-IR trigeminal neurons. In addition, many nitric oxide synthase (NOS)- and parvalbumin (PV)-IR cells of all sizes as well as fewer, mostly large, calbindin D-28k (CB)-containing neurons are seen. The majority of the large ganglion cells are surrounded by SP-, CGRP-, SOM-, CCK-, VIP-, NOS- and serotonin (SER)-IR perisomatic networks. In the MTN, the main subpopulation of large-sized neurons display Glu-immunoreactivity. Additionally, numerous large MTN neurons exhibit PV- and CB-immunostaining. On the other hand, certain small MTN neurons, most likely interneurons, are found to be GABAergic. Furthermore, NOS-containing neurons can be detected in the caudal and the mesencephalic-pontine junction portions of the nucleus. Conversely, no immunoreactivity to any of the examined neuropeptides is observed in the cell bodies of MTN neurons but these are encircled by peptidergic, catecholaminergic, serotonergic and nitrergic perineuronal arborizations in a basket-like manner. Such a discrepancy in the neurochemical features suggests that the differently fated embryonic migration, synaptogenesis, and peripheral and central target field innervation can possibly affect the individual neurochemical phenotypes of trigeminal primary afferent neurons.
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Affiliation(s)
- Nikolai E Lazarov
- Department of Anatomy, Faculty of Medicine, Thracian University, 11 Armejska Street, BG-6003 Stara Zagora, Bulgaria.
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Ichikawa H, Sugimoto T. Vanilloid receptor 1-like receptor-immunoreactive primary sensory neurons in the rat trigeminal nervous system. Neuroscience 2001; 101:719-25. [PMID: 11113320 DOI: 10.1016/s0306-4522(00)00427-9] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Immunohistochemistry for vanilloid receptor 1-like receptor (VRL-1), a candidate transducer for high-threshold noxious heat, was performed on rat trigeminal primary sensory neurons. The immunoreactivity was detected in 14% of the trigeminal ganglion cell bodies, while the neurons in the mesencephalic trigeminal tract nucleus were almost devoid of it (0.5%). The immunoreactive neurons in the trigeminal ganglion were mostly of medium to large size (mean+/-S.D. of 956+/-376microm(2)). Nerve bundles in the tooth pulp, periodontal ligament, facial skin and oral mucosa contained VRL-1-positive smooth nerve fibers. The immunoreactivity could not be traced to the isolated nerve fibers, except in the tooth pulp. In the brainstem trigeminal nuclear complex, a notable concentration of the immunoreactivity was seen in laminae I and II of the medullary dorsal horn. Thirty-seven per cent of the trigeminal ganglion neurons retrogradely labeled from the tooth pulp exhibited VRL-1 immunoreactivity, while the immunoreactivity was detected in only 9% of those labeled from the skin. Co-expression of calcitonin gene-related peptide was common among the VRL-1-immunoreactive tooth pulp neurons (45%) and cutaneous neurons (25%). Moreover, as many as 41% of the VRL-1-immunoreactive tooth pulp neurons co-expressed parvalbumin immunoreactivity. Parvalbumin immunoreactivity was never detected in the VRL-1-immunoreactive cutaneous neurons. From the findings of the present study, we propose that large primary neurons responding to high-threshold noxious heat are abundant in the tooth pulp, but not in the facial skin.
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Affiliation(s)
- H Ichikawa
- Second Department of Oral Anatomy and Biodental Research Center, Okayama University Dental School, 2-5-1 Shikata-cho, 700-8525, Okayama, Japan.
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Slemmon JR, Feng B, Erhardt JA. Small proteins that modulate calmodulin-dependent signal transduction: effects of PEP-19, neuromodulin, and neurogranin on enzyme activation and cellular homeostasis. Mol Neurobiol 2000; 22:99-113. [PMID: 11414283 DOI: 10.1385/mn:22:1-3:099] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Neuromodulin (GAP-43), neurogranin (RC3), and PEP-19 are small acid-stable proteins that bind calcium-poor calmodulin through a loosely conserved IQ-motif. Even though these proteins have been known for many years, much about their function in cells is not understood. It has recently become appreciated that calmodulin activity in cells is tightly controlled and that pools of otherwise free calmodulin are sequestered so as to restrict its availability for activating calcium/calmodulin-dependent enzymes. Neuromodulin, neurogranin, and PEP-19 appear to be major participants in this type of regulation. One way in which they do this is by providing localized increases in the concentration of calmodulin in cells so that the maximal level of target activation is increased. Additionally, they can function as calmodulin antagonists by directly inhibiting the association of calcium/calmodulin with enzymes and other proteins. Although neuromodulin, neurogranin, and PEP-19 were early representatives of the small IQ-motif-containing protein family, newer examples have come to light that expand the number of cellular systems through which the IQ-peptide/calmodulin interaction could regulate biological processes including gene transcription. It is the purpose of this review to examine the behavior of neuromodulin, neurogranin, and PEP-19 in paradigms that include both in vitro and in situ systems in order to summarize possible biological consequences that are linked to the expression of this type of protein. The use of protein:protein interaction chromatography is also examined in the recovery of a new calmodulin-binding peptide, CAP-19 (ratMBF1). Consistent with earlier predictions, at least one function of small IQ-motif proteins appears to be that they lessen the extent to which calcium-calmodulin-dependent enzymes become or stay activated. It also appears that these polypeptides can function to selectively inhibit activation of intracellular targets by some agonists while simultaneously permitting activation of these same targets by other agonists. Much of the mechanism for how this occurs is unknown, and possible explanations are examined. One of the biological consequences for a cell that expresses a calmodulin-regulatory protein could be an increased resistance to calcium-mediated toxicity. This possibility is examined for cells expressing PEP-19 and both anatomical and cell-biological data is described. The study of IQ-motif-containing small proteins has stimulated considerable thought as to how calcium signaling is refined in neurons. Current evidence suggests that signaling through calmodulin is not a fulminating and homogenous process but a spatially limited and highly regulated one. Data from studies on neuromodulin, neurogranin, and PEP-19 suggest that they play an important role in establishing some of the processes by which this regulation is accomplished.
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Affiliation(s)
- J R Slemmon
- Department of Protein Biochemistry, SmithKline Beecham Pharmaceuticals Research and Development, King of Prussia, PA 19406, USA.
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Ichikawa H, Sugimoto T. Peptide 19-immunoreactive primary sensory neurons in the rat trigeminal ganglion. Brain Res 1999; 846:274-9. [PMID: 10556647 DOI: 10.1016/s0006-8993(99)02014-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Peptide 19-immunoreactivity (PEP 19-IR) was examined in the trigeminal ganglion (TG) of the adult rat. A half of TG neurons were immunoreactive(IR) for PEP 19. PEP 19-IR neurons were mostly medium-sized to large. 66% of TG neurons > 600 microm(2) and 38% of those in the range 300-600 microm(2) showed the IR. TG neurons <300 microm(2) were mostly devoid of PEP 19-IR (86%). A double immunofluorescence method revealed the coexpression of PEP 19 and calcium-binding proteins. 31% and 16% of PEP 19-IR neurons exhibited parvalbumin- and calbindin D-28k-IRs, respectively. Conversely, a half of parvalbumin- (53%) and calbindin D-28k-IR (55%) neurons coexpressed PEP 19-IR. PEP 19-IR neurons were mostly IR for S100 (91%) and 80% of S100-IR neurons showed PEP 19-IR. Virtually all (99%) PEP 19-IR neurons were devoid of calcitonin gene-related peptide (CGRP)-IR. The molar tooth pulp contained PEP 19-IR nerve fibers. In the root pulp, PEP 19-IR nerve fibers projected straight until they reached the coronal pulp. Accompanied by blood vessels, these nerve fibers ascended toward the pulp horn. They formed nerve plexuses in the subodontoblastic layer, and reached the base of the odontoblastic layer. However, PEP 19-IR nerve fibers could not be observed within the odontoblastic layer, predentine or dentine. The distribution of these nerve fibers was similar to that of parvalbumin-IR ones. In the TG, PEP 19-IR was found in 34% of primary sensory neurons retrogradely labeled from the molar tooth pulp. 80% of PEP 19-IR tooth pulp TG neurons coexpressed parvalbumin-IR. An immunoelectron microscopic method revealed that a half of radicular axons showed PEP 19-IR. 80% of myelinated axons exhibited PEP 19-IR, whereas 20% of unmyelinated ones showed the IR. In the subodontoblastic layer, PEP 19-IR nerve fibers mostly lost myelin sheath or Schwann cell ensheathment. At the base of the odontoblastic layer, PEP 19-IR neurites made close contact with odontoblasts. PEP 19-IR nerve endings could not be observed in other oro-facial tissues. The coexpression of PEP 19 and CaBPs suggests that low-threshold mechanoreceptors contain PEP 19-IR in the TG. It is also likely that PEP 19-IR TG neurons include myelinated nociceptors.
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Affiliation(s)
- H Ichikawa
- Second Department of Oral Anatomy, Okayama University Dental School, 2-5-1 Shikata-cho, Okayama, Japan
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Ichikawa H, Itota T, Torii Y, Inoue K, Sugimoto T. Osteocalcin-immunoreactive primary sensory neurons in the rat spinal and trigeminal nervous systems. Brain Res 1999; 838:205-9. [PMID: 10446334 DOI: 10.1016/s0006-8993(99)01710-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Osteocalcin-immunoreactivity (OC-ir) was examined in spinal and trigeminal primary sensory neurons of the adult rat. Sixteen percent of dorsal root ganglion (DRG) neurons were immunoreactive (ir) for this protein. These neurons were mostly large and measured 594-4583 microm(2) (mean+/-S.D.=2243+/-748 microm(2)). Thirty-four percent of DRG neurons >1200 microm(2) and 4% of those in the range 600-1200 microm(2) showed the ir. Virtually all DRG neurons <600 microm(2) were devoid of OC-ir. In the trigeminal ganglion (TG), 25% of neurons exhibited the ir. Such neurons were of various sizes (range=156-2825 microm(2), mean+/-S.D.=1234+/-543 microm(2)). Forty-five percent of TG neurons >800 microm(2) and 6% of those <400 microm(2) were immunoreactive for this protein. Twelve percent of TG neurons in the range 400-800 microm(2) showed the ir. In the mesencephalic trigeminal tract nucleus (Mes5), 63% of primary sensory neurons contained OC-ir. Virtually all OC-ir DRG and Mes5 neurons co-expressed parvalbumin-ir but not CGRP-ir. On the other hand, only 31% of OC-ir neurons co-expressed parvalbumin-ir and 10% co-expressed CGRP-ir in the TG. The present study indicates that DRG and Mes5 primary sensory neurons co-expressing OC- and parvalbumin-irs are spinal and trigeminal proprioceptors. OC-ir TG neurons which co-express parvalbumin- and CGRP-irs appear to include low-threshold mechanoreceptors and nociceptors, respectively.
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Affiliation(s)
- H Ichikawa
- Department of Oral Anatomy II, Okayama University Dental School, 2-5-1 Shikata-cho, Okayama 700-8525, Japan
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