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Xie HY, Xu F, Li Y, Zeng ZB, Zhang R, Xu HJ, Qian NS, Zhang YG. Increases in PKC gamma expression in trigeminal spinal nucleus is associated with orofacial thermal hyperalgesia in streptozotocin-induced diabetic mice. J Chem Neuroanat 2015; 63:13-9. [PMID: 25561408 DOI: 10.1016/j.jchemneu.2014.12.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Revised: 12/03/2014] [Accepted: 12/10/2014] [Indexed: 12/16/2022]
Abstract
Painful diabetic polyneuropathy (PDN) at the early phrase of diabetes frequently exhibits increased responsiveness to nociception. In diabetic patients and animal models, alterations in the transmission of orofacial sensory information have been demonstrated in trigeminal system. Herein, we examined the changes of protein kinase Cγ subunit (PKCγ) in trigeminal spinal nucleus (Sp5C) and observed the development of orofacial thermal sensitivity in streptozotocin (STZ)-induced type 1 diabetic mice. With hyperglycemia and body weight loss, STZ mice exhibited orofacial thermal hyperalgesia, along with increased PKCγ expression in Sp5C. Insulin treatment at the early stage of diabetes could alleviate the orofacial thermal hyperalgesia and impaired increased PKCγ in Sp5C in diabetic mice. In summary, our results demonstrate that PKCγ might be involved in orofacial thermal hyperalgesia of diabetes, and early insulin treatment might be effective way to treat orofacial PDN.
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Affiliation(s)
- Hong-Ying Xie
- Department of Cardiology, Daping Hospital and the Research Institute of Surgery of the Third Military Medical University, 400042 Chongqing, China
| | - Fei Xu
- The Oncology Radiotherapy Center of PLA 302 Hospital, Beijing 100039, China
| | - Yue Li
- Department of Vascular Surgery, PLA General Hospital, Beijing, 100853, China
| | - Zhao-Bin Zeng
- Department of Stomatology, General Hospital of Shenyang Military Area Command, Shenyang, China
| | - Ran Zhang
- Department of Cardiology, PLA General Hospital, Beijing, 100853, China
| | - Hui-Jun Xu
- The Oncology Radiotherapy Center of PLA 302 Hospital, Beijing 100039, China
| | - Nian-Song Qian
- Oncology Dept.2of PLA General Hospital, Bejing 100853, China.
| | - Yi-Guan Zhang
- Department of Internal Medicine, Henry Ford Health System, Detroit, MI 48202, USA.
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2
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Dong YL, Wang W, Li H, Li ZH, Zhang FX, Zhang T, Lu YC, Li JL, Wu SX, Li YQ. Neurochemical properties of the synapses in the pathways of orofacial nociceptive reflexes. PLoS One 2012; 7:e34435. [PMID: 22479630 PMCID: PMC3315548 DOI: 10.1371/journal.pone.0034435] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Accepted: 02/28/2012] [Indexed: 11/18/2022] Open
Abstract
The brainstem premotor neurons of the facial nucleus (VII) and hypoglossal (XII) nucleus can integrate orofacial nociceptive input from the caudal spinal trigeminal nucleus (Vc) and coordinate orofacial nociceptive reflex (ONR) responses. However, the synaptoarchitectures of the ONR pathways are still unknown. In the current study, we examined the distribution of GABAergic premotor neurons in the brainstem local ONR pathways, their connections with the Vc projections joining the brainstem ONR pathways and the neurochemical properties of these connections. Retrograde tracer fluoro-gold (FG) was injected into the VII or XII, and anterograde tracer biotinylated dextran amine (BDA) was injected into the Vc. Immunofluorescence histochemical labeling for inhibitory/excitatory neurotransmitters combined with BDA/FG tracing showed that GABAergic premotor neurons were mainly distributed bilaterally in the ponto-medullary reticular formation with an ipsilateral dominance. Some GABAergic premotor neurons made close appositions to the BDA-labeled fibers coming from the Vc, and these appostions were mainly distributed in the parvicellular reticular formation (PCRt), dorsal medullary reticular formation (MdD), and supratrigeminal nucleus (Vsup). We further examined the synaptic relationships between the Vc projecting fibers and premotor neurons in the VII or XII under the confocal laser-scanning microscope and electron microscope, and found that the BDA-labeled axonal terminals that made asymmetric synapses on premotor neurons showed vesicular glutamate transporter 2 (VGluT2) like immunoreactivity. These results indicate that the GABAergic premotor neurons receive excitatory neurotransmission from the Vc and may contribute to modulating the generation of the tonic ONR.
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Affiliation(s)
- Yu-lin Dong
- Department of Anatomy and Histology and Embryology, and K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China
| | - Wen Wang
- Department of Anatomy and Histology and Embryology, and K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China
| | - Hui Li
- Department of Anatomy and Histology and Embryology, and K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China
| | - Zhi-hong Li
- Department of Anatomy and Histology and Embryology, and K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China
| | - Fu-xing Zhang
- Department of Anatomy and Histology and Embryology, and K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China
| | - Ting Zhang
- Department of Anatomy and Histology and Embryology, and K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China
| | - Ya-cheng Lu
- Department of Anatomy and Histology and Embryology, and K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China
| | - Jin-lian Li
- Department of Anatomy and Histology and Embryology, and K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China
- * E-mail: (JL); (SW); (YL)
| | - Sheng-xi Wu
- Department of Anatomy and Histology and Embryology, and K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China
- * E-mail: (JL); (SW); (YL)
| | - Yun-qing Li
- Department of Anatomy and Histology and Embryology, and K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China
- * E-mail: (JL); (SW); (YL)
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3
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DaSilva A, DosSantos M. The role of sensory fiber demography in trigeminal and postherpetic neuralgias. J Dent Res 2012; 91:17-24. [PMID: 21670221 PMCID: PMC3232114 DOI: 10.1177/0022034511411300] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Revised: 03/31/2011] [Accepted: 04/27/2011] [Indexed: 11/17/2022] Open
Abstract
In this study, we systematically investigated fiber demography, based on function and distribution, from the periphery to their destinations in the various central (sub) nuclei in the trigeminal brainstem nuclear sensory complex. Conventional and novel compelling information is provided, demonstrating that the ratio and somatotopy of types A and C sensory fibers at the site of a lesion can elucidate important puzzles in TNP disorders. For instance, we explain how of a major shift in the fibers' direction and ratio at the level of the trigeminal root entry zone (REZ) influences the pathophysiology of pre- and typical trigeminal neuralgia. As a result, there is a high A/C ratio of oral and peri-oral fibers in the supero-medial region of the REZ, which is mostly susceptible to vascular compression. However, this A/C ratio varies considerably at lower proportions in other areas along the peripheral trigeminal pathway, where an injury (viral, vessel compression, or trauma) can lead to a broader spectrum of fiber involvement and, consequently, pain outcome. In summary, we explain how fiber demography can influence pain quality, location, temporal features, progress, and treatment prognosis of TNP in those patients who develop it.
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Affiliation(s)
- A.F. DaSilva
- Headache & Orofacial Pain Effort (H.O.P.E.), Department of Biologic and Materials Sciences and MCOHR, School of Dentistry, University of Michigan, 1011 N. University Ave., Room 1014A, Ann Arbor, MI 48109-1078, USA
- Molecular and Behavioral Neuroscience Institute (MBNI), 205 Zina Pitcher, Room 1021, Ann Arbor, MI 48104, USA
| | - M.F. DosSantos
- Headache & Orofacial Pain Effort (H.O.P.E.), Department of Biologic and Materials Sciences and MCOHR, School of Dentistry, University of Michigan, 1011 N. University Ave., Room 1014A, Ann Arbor, MI 48109-1078, USA
- Faculdade de Medicina, Universidade Federal do Rio de Janeiro, Brazil
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Dong Y, Li J, Zhang F, Li Y. Nociceptive afferents to the premotor neurons that send axons simultaneously to the facial and hypoglossal motoneurons by means of axon collaterals. PLoS One 2011; 6:e25615. [PMID: 21980505 PMCID: PMC3183065 DOI: 10.1371/journal.pone.0025615] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2011] [Accepted: 09/07/2011] [Indexed: 11/19/2022] Open
Abstract
It is well known that the brainstem premotor neurons of the facial nucleus and hypoglossal nucleus coordinate orofacial nociceptive reflex (ONR) responses. However, whether the brainstem PNs receive the nociceptive projection directly from the caudal spinal trigeminal nucleus is still kept unclear. Our present study focuses on the distribution of premotor neurons in the ONR pathways of rats and the collateral projection of the premotor neurons which are involved in the brainstem local pathways of the orofacial nociceptive reflexes of rat. Retrograde tracer Fluoro-gold (FG) or FG/tetramethylrhodamine-dextran amine (TMR-DA) were injected into the VII or/and XII, and anterograde tracer biotinylated dextran amine (BDA) was injected into the caudal spinal trigeminal nucleus (Vc). The tracing studies indicated that FG-labeled neurons receiving BDA-labeled fibers from the Vc were mainly distributed bilaterally in the parvicellular reticular formation (PCRt), dorsal and ventral medullary reticular formation (MdD, MdV), supratrigeminal nucleus (Vsup) and parabrachial nucleus (PBN) with an ipsilateral dominance. Some FG/TMR-DA double-labeled premotor neurons, which were observed bilaterally in the PCRt, MdD, dorsal part of the MdV, peri-motor nucleus regions, contacted with BDA-labeled axonal terminals and expressed c-fos protein-like immunoreactivity which induced by subcutaneous injection of formalin into the lip. After retrograde tracer wheat germ agglutinated horseradish peroxidase (WGA-HRP) was injected into VII or XII and BDA into Vc, electron microscopic study revealed that some BDA-labeled axonal terminals made mainly asymmetric synapses on the dendritic and somatic profiles of WGA-HRP-labeled premotor neurons. These data indicate that some premotor neurons could integrate the orofacial nociceptive input from the Vc and transfer these signals simultaneously to different brainstem motonuclei by axonal collaterals.
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Affiliation(s)
- Yulin Dong
- Department of Anatomy and Histology and Embryology, and K. K. Leung Brain Research Centre, the Fourth Military Medical University, Xi'an, China
| | - Jinlian Li
- Department of Anatomy and Histology and Embryology, and K. K. Leung Brain Research Centre, the Fourth Military Medical University, Xi'an, China
- * E-mail: (JL); (YL)
| | - Fuxing Zhang
- Department of Anatomy and Histology and Embryology, and K. K. Leung Brain Research Centre, the Fourth Military Medical University, Xi'an, China
| | - Yunqing Li
- Department of Anatomy and Histology and Embryology, and K. K. Leung Brain Research Centre, the Fourth Military Medical University, Xi'an, China
- * E-mail: (JL); (YL)
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5
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Barceló AC, Filippini B, Pazo JH. The striatum and pain modulation. Cell Mol Neurobiol 2011; 32:1-12. [PMID: 21789630 DOI: 10.1007/s10571-011-9737-7] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2010] [Accepted: 07/02/2011] [Indexed: 10/18/2022]
Abstract
The aim of this review was to give a general aspect of the sensorial function of the striatum related to pain modulation, which was intensively studied in our laboratory. We analyse the effect of electrical and chemical stimulation of the striatum on the orofacial pain, especially that produced by tooth pulp stimulation of the lower incisors. We demonstrated specific sites within the nucleus which electrical or chemical stimulation produced inhibition of the nociceptive jaw opening reflex. This analgesic action of the striatum was mediated by activation of its dopamine D(2) receptors and transmitted through the indirect pathways of the basal ganglia and the medullary dorsal reticular nucleus (RVM) to the sensorial nuclei of the trigeminal nerve. Its mechanism of action was by inhibition of the nociceptive response of the second order neurons of the nucleus caudalis of the V par.
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Affiliation(s)
- Ana C Barceló
- Facultad de Odontología, Universidad de Buenos Aires, Cátedra de Fisiología, Buenos Aires, Argentina
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Borsani E, Albertini R, Labanca M, Lonati C, Rezzani R, Rodella LF. Peripheral purinergic receptor modulation influences the trigeminal ganglia nitroxidergic system in an experimental murine model of inflammatory orofacial pain. J Neurosci Res 2011; 88:2715-26. [PMID: 20648657 DOI: 10.1002/jnr.22420] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
ATP plays an important role as an endogenous pain mediator generating and/or modulating pain signaling from the periphery to the central nervous system. The aim of this study was to analyze the role of peripheral purinergic receptors in modulation of the nitroxidergic system at a trigeminal ganglia level by monitoring changes in nitric oxide synthase isoforms. We also evaluated Fos-positive neurons in brainstem (spinal trigeminal nucleus) and pain-related behavior. We found that local administration of the P2 purinergic receptor antagonist pyridoxalphosphate-6-azophenyl-2',4'-disulphonic acid (PPADS) decreased face-rubbing activity, nitric oxide synthase isoform expression in trigeminal ganglia, and Fos expression in spinal trigeminal nucleus after subcutaneous injection of formalin. These results suggest a role for peripheral P2 purinergic receptors in orofacial pain transmission through modulation of the nitroxidergic system. .
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Affiliation(s)
- Elisa Borsani
- Division of Human Anatomy, Department of Biomedical Sciences and Biotechnologies, Brescia University, 25123 Brescia, Italy
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7
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Lavezzi AM, Mehboob R, Matturri L. Developmental alterations of the spinal trigeminal nucleus disclosed by substance P immunohistochemistry in fetal and infant sudden unexplained deaths. Neuropathology 2011; 31:405-13. [PMID: 21276082 DOI: 10.1111/j.1440-1789.2010.01190.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We investigated the immunohistochemical expression of substance P (SP) in the brainstems of 56 subjects aged from 17 gestational weeks to 10 post natal months, who died of unknown (sudden unexplained fetal deaths and SIDS) and known causes (controls). The goals of this study were: (i) to obtain basic information about the expression of SP during the first phases of human nervous system development; (ii) to evaluate whether there are alterations of this neuromodulator in victims of sudden death; and (iii) to verify any correlation with maternal cigarette smoking. Immunohistochemistry demonstrated SP immunoreactivity in the caudal trigeminal nucleus area, with a progressive increase in the density of SP-positive fibers of the corresponding tract during normal development from fetal life to the first post natal months. Delineation of the structure of the human trigeminal nucleus, little investigated so far, provided essential data on its morphologic and functional development. Instead, a negative or low SP expression was detectable in the fibers of this tract in a wide subset of SIDS victims and, conversely, a high SP-expression in a wide subset of sudden fetal deaths. We postulate, on the basis of these results, that SP has a functional importance in the early phases of central nervous system development and in the regulation of autonomic functions. In addition, the observation of a significant correlation between sudden unexplained death, altered SP staining and maternal smoking leads us to suggest a close relation between the absorption of cigarette smoke in utero and a decreased functional activity of the trigeminal nucleus, that can trigger sudden death of the fetus during pregnancy or of the infant in the first months of life.
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Affiliation(s)
- Anna M Lavezzi
- Lino Rossi Research Center for the Study and Prevention of Unexpected Perinatal Death and SIDS, Department of Surgical, Reconstructive and Diagnostic Sciences, University of Milan, Milan, Italy.
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Ultrastructural Basis for Craniofacial Sensory Processing in The Brainstem. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2011. [DOI: 10.1016/b978-0-12-385198-7.00005-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
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9
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Kim YS, Son JY, Kim TH, Paik SK, Dai Y, Noguchi K, Ahn DK, Bae YC. Expression of transient receptor potential ankyrin 1 (TRPA1) in the rat trigeminal sensory afferents and spinal dorsal horn. J Comp Neurol 2010; 518:687-98. [PMID: 20034057 DOI: 10.1002/cne.22238] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Transient receptor potential ankyrin 1 (TRPA1), responding to noxious cold and pungent compounds, is implicated in the mediation of nociception, but little is known about the processing of the TRPA1-mediated nociceptive information within the trigeminal sensory nuclei (TSN) and the spinal dorsal horn (DH). To address this issue, we characterized the TRPA1-positive (+) neurons in the trigeminal ganglion (TG) and investigated the distribution of TRPA1(+) afferent fibers and their synaptic connectivity within the rat TSN and DH by using light and electron microscopic immunohistochemistry. In the TG, TRPA1 was expressed in unmyelinated and small myelinated axons and also occasionally in large myelinated axons. Many TRPA1(+) neurons costained for the marker for peptidergic neurons substance P (26.8%) or the marker for nonpeptidergic neurons IB4 (44.5%). In the CNS, small numbers of axons and terminals were immunopositive for TRPA1 throughout the rostral TSN, in contrast to the dense network of positive fibers and terminals in the superficial laminae of the trigeminal caudal nucleus (Vc) and DH. The TRPA1(+) terminals contained clear round vesicles, were presynaptic to one or two dendrites, and rarely participated in axoaxonic contacts, suggesting involvement in relatively simple synaptic circuitry with a small degree of synaptic divergence and little presynaptic modulation. Immunoreactivity for TRPA1 was also occasionally observed in postsynaptic dendrites. These results suggest that TRPA1-dependent orofacial and spinal nociceptive input is processed mainly in the superficial laminae of the Vc and DH in a specific manner and may be processed differently between the rostral TSN and Vc.
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Affiliation(s)
- Yun Sook Kim
- Department of Oral Anatomy and Neurobiology, Kyungpook National University, Daegu, Korea
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Nash PG, Macefield VG, Klineberg IJ, Murray GM, Henderson LA. Differential activation of the human trigeminal nuclear complex by noxious and non-noxious orofacial stimulation. Hum Brain Mapp 2010; 30:3772-82. [PMID: 19492300 DOI: 10.1002/hbm.20805] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
There is good evidence from animal studies for segregation in the processing of non-nociceptive and nociceptive information within the trigeminal brainstem sensory nuclear complex. However, it remains unknown whether a similar segregation occurs in humans, and a recent tract tracing study suggests that this segregation may not exist. We used functional magnetic resonance imaging (fMRI) to define and compare activity patterns of the trigeminal brainstem nuclear complex during non-noxious and noxious cutaneous and non-noxious and noxious muscle orofacial stimulation in humans. We found that during cutaneous pain, signal intensity increased within the entire rostrocaudal extent of the spinal trigeminal nucleus (SpV), encompassing the ipsilateral oralis (SpVo), interpolaris (SpVi) and caudalis (SpVc) subdivisions. In contrast, muscle pain did not activate SpVi, but instead activated a discrete region of the ipsilateral SpVo and SpVc. Further, muscle noxious stimulation activated a region of the ipsilateral lateral pons in the region of the trigeminal principal sensory nucleus (Vp). Innocuous orofacial stimulation (lip brushing) also evoked a significant increase in signal intensity in the ipsilateral Vp; however, non-noxious muscle stimulation showed no increase in signal in this area. The data reveal that orofacial cutaneous and muscle nociceptive information and innocuous cutaneous stimulation are differentially represented within the trigeminal nuclear complex. It is well established that cutaneous and muscle noxious stimuli evoke different perceptual, behavioural and cardiovascular changes. We speculate that the differential activation evoked by cutaneous and muscle noxious stimuli within the trigeminal sensory complex may contribute to the neural basis for these differences.
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Affiliation(s)
- Paul G Nash
- Department of Anatomy and Histology, University of Sydney, New South Wales, Australia
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11
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Kim YS, Paik SK, Cho YS, Shin HS, Bae JY, Moritani M, Yoshida A, Ahn DK, Valtschanoff J, Hwang SJ, Moon C, Bae YC. Expression of P2X3 receptor in the trigeminal sensory nuclei of the rat. J Comp Neurol 2007; 506:627-39. [DOI: 10.1002/cne.21544] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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12
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Park SJ, Zhang S, Chiang CY, Hu JW, Dostrovsky JO, Sessle BJ. Central sensitization induced in thalamic nociceptive neurons by tooth pulp stimulation is dependent on the functional integrity of trigeminal brainstem subnucleus caudalis but not subnucleus oralis. Brain Res 2006; 1112:134-45. [PMID: 16930568 DOI: 10.1016/j.brainres.2006.06.115] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2006] [Revised: 06/23/2006] [Accepted: 06/25/2006] [Indexed: 11/21/2022]
Abstract
We have previously demonstrated that application of the inflammatory irritant mustard oil (MO) to the rat molar tooth pulp induces central sensitization in nociceptive neurons within the contralateral ventroposterior medial (VPM) nucleus and posterior nuclear group (PO) of the thalamus as well as brainstem subnucleus caudalis (Vc) and subnucleus oralis (Vo). Since Vc and Vo are important relays of pulp afferent input to thalamus, the aim of this study was to test if local application of the synaptic blocker CoCl2 to Vc or Vo influences the pulp-induced thalamic central sensitization. The activity of 32 nociceptive-specific (NS) neurons within the rat VPM and immediately adjacent PO was recorded. Spontaneous activity, mechanoreceptive field (RF), mechanical activation threshold and evoked responses to graded mechanical stimuli were assessed before and after MO application to the pulp. MO application evoked immediate but short-lasting neuronal discharges in 21 of the 32 NS neurons tested, as well as central sensitization reflected in significant and long-lasting (> 60 min) RF expansion, decrease in activation threshold, and increase in graded pinch-evoked responses in all 32 NS neurons. CoCl2 applied to the ipsilateral Vc significantly attenuated these pulp-induced changes for 20 min or more. In contrast, CoCl2 applied to the ipsilateral Vo did not reverse this MO-induced central sensitization. Isotonic saline applied to Vc or Vo was also ineffective. These findings indicate that central sensitization induced in nociceptive neurons within VPM and PO by noxious stimulation of the tooth pulp is dependent upon the functional integrity of Vc but not Vo.
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Affiliation(s)
- Soo Joung Park
- Faculty of Dentistry, University of Toronto, 124 Edward Street, Toronto, ON, Canada M5G 1G6
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Belforte JE, Pazo JH. Striatal Inhibition of Nociceptive Responses Evoked in Trigeminal Sensory Neurons by Tooth Pulp Stimulation. J Neurophysiol 2005; 93:1730-41. [PMID: 15738277 DOI: 10.1152/jn.00496.2004] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The noxious evoked response in trigeminal sensory neurons was studied to address the role of striatum in the control of nociceptive inputs. In urethane-anesthetized rats, the jaw opening reflex (JOR) was produced by suprathreshold stimulation of the tooth pulp and measured as electromyographic response in the digastric muscle, with simultaneous recording of noxious responses in single unit neurons of the spinal trigeminal nucleus pars caudalis (Sp5c). The microinjection of glutamate (80 ηmol/0.5 μl) into striatal JOR inhibitory sites significantly decreased the Aδ and C fiber–mediated–evoked response (53 ± 4.2 and 43.6 ± 6.4% of control value, P < 0.0001) in 92% (31/34) of nociceptive Sp5c neurons. The microinjection of the solvent was ineffective, as was microinjection of glutamate in sites out of the JOR inhibitory ones. In another series of experiments, simultaneous single unit recordings were performed in the motor trigeminal nucleus (Mo5) and the Sp5c nucleus. Microinjection of glutamate decreased the noxious-evoked response in Sp5c and Mo5 neurons in parallel with the JOR, without modifying spontaneous neuronal activity of trigeminal motoneurons ( n = 8 pairs). These results indicate that the striatum could be involved in the modulation of nociceptive inputs and confirm the role of the basal ganglia in the processing of nociceptive information.
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Affiliation(s)
- Juan E Belforte
- Laboratorio de Neurofisiología, Deptartamento de Fisiología, Facultad de Medicina, Universidad de Buenos Aires, Paraguay 2155, Buenos Aires 1121, Argentina
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Abstract
The brainstem trigeminal complex integrates somatosensory inputs from orofacial areas and meninges. Recent studies have shown the existence of a double representation of pain within the brainstem, at the level of both caudalis and oralis subnuclei. Noxious messages are mainly conveyed by C-fibers that activate the subnucleus caudalis neurons. These neurons in turn activate the subnucleus oralis whose neurons share similar features with the deep spinal dorsal horn neurons. In contrast with the nearness of the laminar organization of the dorsal horn, the vertical organization of the trigeminal complex offers an easier access for the study of segmental mechanisms of nociceptive processing. This model allowed us to show the existence of subtle NMDA-related mechanisms of segmental nocious processing. The trigeminal complex conveys nociceptive messages to several brainstem and thalamic relays that activate a number of cortical areas responsible for pain sensations and reactions. Cortical processing is sustained by reciprocal interactions with thalamic areas and also by a direct modulation of their pre-thalamic relays. The dysfunction of these multiple modulatory mechanisms probably plays a key role in the pathophysiology of chronic trigeminal pain.
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Affiliation(s)
- Radhouane Dallel
- Inserm E 0216, Neurobiologie de la douleur trigéminale, Faculté de chirurgie dentaire, 11, boulevard Charles de Gaulle, 63000 Clermont-Ferrand, France.
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Arreto CD, Robert C, Limoge A, Gaudy JF. Use of the jaw opening reflex for assessing the effects of local anaesthetics in freely moving rats. J Pharmacol Toxicol Methods 2002; 48:45-51. [PMID: 12750041 DOI: 10.1016/s1056-8719(03)00020-0] [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] [Indexed: 11/20/2022]
Abstract
INTRODUCTION In order to characterize a nonbehavioral model for assessing local anaesthetic (LA) activity, the effects of different LA agents (articaine, bupivacaine, procaine, and tetracaine) were measured in the conscious rat using the jaw-opening reflex (JOR). METHODS One hundred sixty rats were chronically implanted with stimulating electrodes in the dental pulp of the low incisor. While animals were conscious and unrestrained, the JOR threshold was measured electrophysiologically via electrodes wrapped around the digastric muscle. Each LA was administered in the infratemporal area. The increase of the JOR threshold was assessed during a 3-h period following injection. RESULTS Statistical analysis of the data showed a dose-dependent response to the four drugs tested. When the highest dose of each drug (articaine and procaine: 24 mg kg(-1), bupivacaine: 6 mg kg(-1), tetracaine: 3 mg kg(-1)) was administered (i) an immediate effect was observed for tetracaine and bupivacaine, whereas a 5-min delay was needed for articaine and procaine to act on the JOR threshold and (ii) an increase (>60%) of the JOR threshold was observed. The effects lasted 90 min for articaine, 45 min for procaine and bupivacaine, and 15 min for tetracaine before a return to baseline values. DISCUSSION The rat JOR response combined with infratemporal injection of test drugs can be used for the pharmacological evaluation of LAs.
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Affiliation(s)
- C-D Arreto
- Laboratoire d'Anatomie fonctionnelle de l'appareil manducateur, Université René Descartes-Paris 5, 1, rue Maurice Arnoux, 92 120, Montrouge, France.
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Chiang CY, Hu B, Hu JW, Dostrovsky JO, Sessle BJ. Central sensitization of nociceptive neurons in trigeminal subnucleus oralis depends on integrity of subnucleus caudalis. J Neurophysiol 2002; 88:256-64. [PMID: 12091551 DOI: 10.1152/jn.00944.2001] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Our recent studies have shown that application to the tooth pulp of the inflammatory irritant mustard oil (MO) produces a prolonged (>40 min) "central sensitization" reflected in neuroplastic changes in the mechanoreceptive field (RF) and response properties of nociceptive brain stem neurons in subnuclei oralis (Vo) and caudalis (Vc) of the trigeminal spinal tract nucleus. In view of the previously demonstrated ascending modulatory influence of Vc on Vo, our aim was to determine whether the Vo neuroplastic changes induced by MO application to the tooth pulp depend on an ascending influence from Vc. In chloralose/urethan-anesthetized rats, MO application to the pulp produced significant increases in Vo nociceptive neuronal orofacial RF size and responses to mechanical noxious stimuli that lasted as long as 40-60 min. These changes were not affected by vehicle (saline) microinjected into Vc at 20 min after MO application, but 0.3 microl of a 5 mM CoCl(2) solution microinjected into the ipsilateral Vc produced a reversible blockade of the MO-induced Vo neuroplastic changes. A similar volume and concentration of CoCl(2) solution injected into subnucleus interpolaris of the trigeminal spinal tract nucleus did not affect the MO-induced neuroplastic changes in Vo. These findings indicate that inflammatory pulp-induced central sensitization in Vo is dependent on the functional integrity of Vc.
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Affiliation(s)
- Chen Yu Chiang
- Faculty of Dentistry, University of Toronto, Ontario M5G 1G6, Canada
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Pajot J, Pelissier T, Sierralta F, Raboisson P, Dallel R. Differential effects of trigeminal tractotomy on Adelta- and C-fiber-mediated nociceptive responses. Brain Res 2000; 863:289-92. [PMID: 10773221 DOI: 10.1016/s0006-8993(00)02157-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In this study we have tested in the rat, whether trigeminal tractotomy, which deprives the spinal trigeminal nucleus caudalis (Sp5C) of its trigeminal inputs, affected differentially nociceptive responses mediated by C- vs. Adelta-nociceptors from oral and perioral regions. Tractotomy had no effect on the threshold of the jaw opening reflex, induced by incisive pulp stimulation (Adelta-fiber-mediated), but blocked the formalin response (mainly C-fiber-mediated). These results suggest that nociceptive responses mediated by trigeminal C-fibers completely depend on the integrity of the Sp5C, while intraoral sensations triggered Adelta-fibers (especially of dental origin) are primarily processed in the rostral part of the spinal trigeminal nucleus.
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Affiliation(s)
- J Pajot
- Laboratoire de Physiologie Oro-Faciale, Faculté de Chirurgie Dentaire, 11 Bd Charles de Gaulle, 63000, Clermont-Ferrand, France
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