51
|
Shibuta K, Suzuki I, Shinoda M, Tsuboi Y, Honda K, Shimizu N, Sessle BJ, Iwata K. Organization of hyperactive microglial cells in trigeminal spinal subnucleus caudalis and upper cervical spinal cord associated with orofacial neuropathic pain. Brain Res 2012; 1451:74-86. [PMID: 22459040 DOI: 10.1016/j.brainres.2012.02.023] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Revised: 02/07/2012] [Accepted: 02/09/2012] [Indexed: 10/28/2022]
Abstract
The aim of this study was to evaluate spatial organization of hyperactive microglial cells in trigeminal spinal subnucleus caudalis (Vc) and upper cervical spinal cord (C1), and to clarify the involvement in mechanisms underlying orofacial secondary hyperalgesia following infraorbital nerve injury. We found that the head-withdrawal threshold to non-noxious mechanical stimulation of the maxillary whisker pad skin was significantly reduced in chronic constriction injury of the infraorbital nerve (ION-CCI) rats from day 1 to day 14 after ION-CCI. On day 3 after ION-CCI, mechanical allodynia was obvious in the orofacial skin areas innervated by the 1st and 3rd branches of the trigeminal nerve as well as the 2nd branch area. Hyperactive microglial cells in Vc and C1 were observed on days 3 and 7 after ION-CCI. On day 3 after ION-CCI, a large number of phosphorylated extracellular signal-regulated kinase (pERK)-immunoreactive (IR) cells were observed in Vc and C1. Many hyperactive microglial cells were also distributed over a wide area of Vc and C1 innervated by the trigeminal nerve. The intraperitoneal administration of minocycline significantly reduced the activation of microglial cells and the number of pERK-IR cells in Vc and C1, and also significantly attenuated the development of mechanical allodynia. Furthermore, enhanced background activity and mechanical evoked responses of Vc wide dynamic range neurons in ION-CCI rats were significantly reversed following minocycline administration. These findings suggest that activation of microglial cells over a wide area of Vc and C1 is involved in the enhancement of Vc and C1 neuronal excitability in the early period after ION-CCI, resulting in the neuropathic pain in orofacial areas innervated by the injured as well as uninjured nerves.
Collapse
Affiliation(s)
- Kazuo Shibuta
- Department of Orthodontics, Nihon University School of Dentistry, 1-8-13 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan
| | | | | | | | | | | | | | | |
Collapse
|
52
|
Ayles S, Graven-Nielsen T, Gibson W. Vibration-Induced Afferent Activity Augments Delayed Onset Muscle Allodynia. THE JOURNAL OF PAIN 2011; 12:884-91. [DOI: 10.1016/j.jpain.2011.02.355] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2010] [Revised: 01/18/2011] [Accepted: 02/10/2011] [Indexed: 11/27/2022]
|
53
|
Kobayashi A, Shinoda M, Sessle BJ, Honda K, Imamura Y, Hitomi S, Tsuboi Y, Okada-Ogawa A, Iwata K. Mechanisms involved in extraterritorial facial pain following cervical spinal nerve injury in rats. Mol Pain 2011; 7:12. [PMID: 21310020 PMCID: PMC3048571 DOI: 10.1186/1744-8069-7-12] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2010] [Accepted: 02/10/2011] [Indexed: 11/21/2022] Open
Abstract
Background The aim of this study is to clarify the neural mechanisms underlying orofacial pain abnormalities after cervical spinal nerve injury. Nocifensive behavior, phosphorylated extracellular signal-regulated kinase (pERK) expression and astroglial cell activation in the trigeminal spinal subnucleus caudalis (Vc) and upper cervical spinal dorsal horn (C1-C2) neurons were analyzed in rats with upper cervical spinal nerve transection (CNX). Results The head withdrawal threshold to mechanical stimulation of the lateral facial skin and head withdrawal latency to heating of the lateral facial skin were significantly lower and shorter respectively in CNX rats compared to Sham rats. These nocifensive effects were apparent within 1 day after CNX and lasted for more than 21 days. The numbers of pERK-like immunoreactive (LI) cells in superficial laminae of Vc and C1-C2 were significantly larger in CNX rats compared to Sham rats following noxious and non-noxious mechanical or thermal stimulation of the lateral facial skin at day 7 after CNX. Two peaks of pERK-LI cells were observed in Vc and C1-C2 following mechanical and heat stimulation of the lateral face. The number of pERK-LI cells in C1-C2 was intensity-dependent and increased when the mechanical and heat stimulations of the face were increased. The decrements of head withdrawal latency to heat and head withdrawal threshold to mechanical stimulation were reversed during intrathecal (i.t.) administration of MAPK/ERK kinase 1/2 inhibitor PD98059. The area of activated astroglial cells was significantly higher in CNX rats (at day 7 after CNX). The heat and mechanical nocifensive behaviors were significantly depressed and the number of pERK-LI cells in Vc and C1-C2 following noxious and non-noxious mechanical stimulation of the face was also significantly decreased following i.t. administration of the astroglial inhibitor fluoroacetate. Conclusions The present findings have demonstrated that mechanical allodynia and thermal hyperalgesia occur in the lateral facial skin after CNX and also suggest that ERK phosphorylation of Vc and C1-C2 neurons and astroglial cell activation are involved in orofacial extraterritorial pain following cervical nerve injury.
Collapse
Affiliation(s)
- Azusa Kobayashi
- Department of Oral Diagnosis, Nihon University School of Dentistry, 1-8-13 Kandasurugadai, Chiyoda-ku, Tokyo, 101-8310, Japan
| | | | | | | | | | | | | | | | | |
Collapse
|
54
|
Bereiter DA, Okamoto K. Neurobiology of estrogen status in deep craniofacial pain. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2011; 97:251-84. [PMID: 21708314 DOI: 10.1016/b978-0-12-385198-7.00010-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Pain in the temporomandibular joint (TMJ) region often occurs with no overt signs of injury or inflammation. Although the etiology of TMJ-related pain may involve multiple factors, one likely risk factor is female gender or estrogen status. Evidence is reviewed from human and animal studies, supporting the proposition that estrogen status acts peripherally or centrally to influence TMJ nociceptive processing. A new model termed the "TMJ pain matrix" is proposed as critical for the initial integration of TMJ-related sensory signals in the lower brainstem that is both modified by estrogen status, and closely linked to endogenous pain and autonomic control pathways.
Collapse
Affiliation(s)
- David A Bereiter
- Department of Diagnostic and Biological Sciences, University of Minnesota School of Dentistry, Minneapolis, MN 55455, USA
| | | |
Collapse
|
55
|
Gazerani P, Au S, Dong X, Kumar U, Arendt-Nielsen L, Cairns BE. Botulinum neurotoxin type A (BoNTA) decreases the mechanical sensitivity of nociceptors and inhibits neurogenic vasodilation in a craniofacial muscle targeted for migraine prophylaxis. Pain 2010; 151:606-616. [PMID: 20728992 DOI: 10.1016/j.pain.2010.07.029] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2010] [Revised: 07/14/2010] [Accepted: 07/27/2010] [Indexed: 11/24/2022]
Abstract
The mechanism by which intramuscular injection of BoNTA into the craniofacial muscles decreases migraine headaches is not known. In a blinded study, the effect of BoNTA on the mechanical and chemical responsiveness of individual temporalis muscle nociceptors and muscle neurogenic vasodilation was investigated in female rats. Mechanical threshold was measured for 3h following intramuscular injection of BoNTA or vehicle, and for 10 min after a subsequent injection of the algogen glutamate. Injection of BoNTA significantly increased the mechanical threshold of muscle nociceptors without altering the muscle surface temperature and blocked glutamate-induced mechanical sensitization and neurogenic vasodilation. None of these effects were reproduced by pancuronium-induced muscle paralysis. Western blot analysis of temporalis muscles indicated that BoNTA significantly decreased SNAP-25. Measurement of interstitial glutamate concentration with a glutamate biosensor indicated that BoNTA significantly reduced glutamate concentrations. The mechanical sensitivity of muscle nociceptors is modulated by glutamate concentration through activation of peripheral NMDA receptors. Immunohistochemical experiments were conducted and they indicated that half of the NMDA-expressing temporalis nerve fibers co-expressed substance P or CGRP. Additional electrophysiology experiments examined the effect of antagonists for NMDA, CGRP and NK1 receptors on glutamate-induced effects. Glutamate-induced mechanical sensitization was only blocked by the NMDA receptor antagonist, but muscle neurogenic vasodilation was attenuated by NMDA or CGRP receptor antagonists. These data suggest that injection of BoNTA into craniofacial muscles acts to decrease migraine headaches by rapidly decreasing the mechanical sensitivity of temporalis muscle nociceptors through inhibition of glutamate release and by attenuating the provoked release of CGRP from muscle nociceptors.
Collapse
Affiliation(s)
- Parisa Gazerani
- The Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, BC, Canada Center for Sensory-Motor Interaction (SMI), Dept. of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | | | | | | | | | | |
Collapse
|
56
|
Armijo-Olivo S, Fuentes JP, da Costa BR, Major PW, Warren S, Thie NMR, Magee DJ. Reduced endurance of the cervical flexor muscles in patients with concurrent temporomandibular disorders and neck disability. ACTA ACUST UNITED AC 2010; 15:586-92. [PMID: 20688556 DOI: 10.1016/j.math.2010.07.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2009] [Revised: 06/25/2010] [Accepted: 07/06/2010] [Indexed: 10/19/2022]
Abstract
Subjects with temporomandibular disorders (TMDs) have been found to have clinical signs and symptoms of cervical dysfunction. Although many studies have investigated the relationship between the cervical spine and TMD, no study has evaluated the endurance capacity of the cervical muscles in patients with TMD. Thus the objective of this study was to determine whether patients with TMD had a reduced endurance of the cervical flexor muscles at any level of muscular contraction when compared with healthy subjects. One hundred and forty-nine participants provided data for this study (49 subjects were healthy, 54 had myogenous TMD, and 46 had mixed TMD). There was a significant difference in holding time at 25% MVC between subjects with mixed TMD when compared to subjects with myogenous TMD and healthy subjects. This implies that subjects with mixed TMD had less endurance capacity at a lower level of contraction (25% MVC) than healthy subjects and subjects with myogenous TMD. No significant associations between neck disability, jaw disability, clinical variables and neck flexor endurance test were found.
Collapse
Affiliation(s)
- Susan Armijo-Olivo
- Department of Physical Therapy, Faculty of Rehabilitation Medicine, University of Alberta, 3-48 Corbett Hall, Edmonton, Alberta T6G 2G4, Canada.
| | | | | | | | | | | | | |
Collapse
|
57
|
Devoize L, Doméjean S, Melin C, Raboisson P, Artola A, Dallel R. Organization of projections from the spinal trigeminal subnucleus oralis to the spinal cord in the rat: A neuroanatomical substrate for reciprocal orofacial–cervical interactions. Brain Res 2010; 1343:75-82. [DOI: 10.1016/j.brainres.2010.04.076] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2010] [Revised: 04/27/2010] [Accepted: 04/28/2010] [Indexed: 10/19/2022]
|
58
|
Fernández-Mayoralas DM, Fernández-de-las-Peñas C, Palacios-Ceña D, Cantarero-Villanueva I, Fernández-Lao C, Pareja JA. Restricted neck mobility in children with chronic tension type headache: a blinded, controlled study. J Headache Pain 2010; 11:399-404. [PMID: 20508963 PMCID: PMC3452272 DOI: 10.1007/s10194-010-0224-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2010] [Accepted: 05/12/2010] [Indexed: 12/31/2022] Open
Abstract
The main purpose of this study was to analyze the differences in neck mobility between children with chronic tension type headache (CTTH) and healthy children, and to determine the influence of cervical mobility on headache intensity, frequency and duration. Fifty children, 13 boys and 37 girls (mean age 8.5 ± 1.6 years) with CTTH associated to peri-cranial tenderness (IHS 2.3.1) and 50 age- and sex matched children without headache (13 boys, 37 girls, mean age 8.5 ± 1.8 years, P = 0.955) participated. Cervical range of motion (CROM) was objectively assessed with a cervical goniometer by an assessor blinded to the children’s condition. Children completed a headache diary for 4 weeks to confirm the diagnosis. Children with CTTH showed decreased CROM as compared to children without headache for flexion (z = −6.170; P < 0.001), extension (z = −4.230; P < 0.001), right (z = −4.505; P < 0.001) and left (z = −4.768; P < 0.001) lateral-flexions, but not for rotation (right z = −0.802; P = 0.425; left z = −1.254; P = 0.213) and also for total range of motion for flexion-extension (z = −4.267; P < 0.001) and lateral-flexion (z = −4.801; P < 0.001), but not for rotation (z = −1.058; P = 0.293). Within CTTH children, CROM was not correlated with headache intensity, frequency or duration. Additionally, age (P > 0.125) or gender (P > 0.250) did not influence CROM in either children with CTTH or without headache. Current results support the hypothesis that the cervical spine should be explored in children with headache. Further research is also needed to clearly define the potential role of the cervical spine in the genesis or maintenance of CTTH.
Collapse
|
59
|
Referred pain from muscle trigger points in the masticatory and neck-shoulder musculature in women with temporomandibular disoders. THE JOURNAL OF PAIN 2010; 11:1295-304. [PMID: 20494623 DOI: 10.1016/j.jpain.2010.03.005] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2010] [Revised: 02/25/2010] [Accepted: 03/05/2010] [Indexed: 01/18/2023]
Abstract
UNLABELLED Our aim was to describe the referred pain patterns and size of areas of trigger points (TrPs) in the masticatory and neck-shoulder muscles of women with myofascial temporomandibular disorders (TMD). Twenty-five women with myofascial TMD and 25 healthy matched women participated. Bilateral temporalis, deep masseter, superficial masseter, sternocleidomastoid, upper trapezius and suboccipital muscles were examined for TrPs by an assessor blinded to the subjects' condition. TrPs were identified with manual palpation and categorized into active and latent according to proposed criteria. The referred pain areas were drawn on anatomical maps, digitalized, and measured. The occurrence of active (P < .001) and latent TrPs (P = .04) were different between groups. In all muscles, there were significantly more active and latent TrP in patients than controls (P < .001). Significant differences in referred pain areas between groups (P < .001) and muscles (P < .001) were found: the referred pain areas were larger in patients (P < .001), and the referred pain area elicited by suboccipital TrPs was greater than the referred pain from other TrPs (P < .001). Referred pain areas from neck TrPs were greater than the pain areas from masticatory muscle TrPs (P < .01). Referred pain areas of masticatory TrPs were not different (P > .703). The local and referred pain elicited from active TrPs in the masticatory and neck-shoulder muscles shared similar pain pattern as spontaneous TMD, which supports the concept of peripheral and central sensitization mechanisms in myofascial TMD. PERSPECTIVE The current study showed the existence of multiple active muscle TrPs in the masticatory and neck-shoulder muscles in women with myofascial TMD pain. The local and referred pain elicited from active TrPs reproduced pain complaints in these patients. Further, referred pain areas were larger in TMD pain patients than in healthy controls. The results are also in accordance with the notion of peripheral and central sensitization mechanisms in patients with myofascial TMD.
Collapse
|
60
|
|
61
|
Inoue E, Maekawa K, Minakuchi H, Nagamatsu-Sakaguchi C, Ono T, Matsuka Y, Clark GT, Kuboki T. The relationship between temporomandibular joint pathosis and muscle tenderness in the orofacial and neck/shoulder region. ACTA ACUST UNITED AC 2010; 109:86-90. [PMID: 20123380 DOI: 10.1016/j.tripleo.2009.07.050] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2009] [Revised: 07/16/2009] [Accepted: 07/27/2009] [Indexed: 11/17/2022]
Abstract
OBJECTIVE The objective of this study was to investigate the association between TMJ pain/disk pathosis and the muscle tenderness pattern in the orofacial and neck/shoulder region. STUDY DESIGN One hundred seventy-one TMD patients were divided into 4 groups, including group 1: patients with painful unilateral TMJ disk displacement (DD); group 2: patients with painless unilateral TMJ DD; group 3: patients with painless bilateral TMJ DD; and group 4: patients with a bilateral normal TMJ disk position (n = 41). Each subject underwent muscle palpation and the side-by-side number of muscle tenderness points was combined as the number of muscle tenderness points on each side. Within each group, DD with and without reduction subjects were separated into subgroups and then were analyzed. RESULTS In group 1, the median muscle tenderness points on the side with painful TMJ DD without reduction was significantly higher than on the normal side (P = .019), whereas the palpation scores for painless DD patients showed no significant difference between the DD and normal sides. CONCLUSIONS These results indicated painful disk displacement to possibly be correlated with ipsilateral muscle tenderness.
Collapse
Affiliation(s)
- Eitoku Inoue
- Department of Oral Rehabilitation and Regenerative Medicine, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan
| | | | | | | | | | | | | | | |
Collapse
|
62
|
Cairns BE. Pathophysiology of TMD pain--basic mechanisms and their implications for pharmacotherapy. J Oral Rehabil 2010; 37:391-410. [PMID: 20337865 DOI: 10.1111/j.1365-2842.2010.02074.x] [Citation(s) in RCA: 186] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
This article discusses the pathophysiology of temporomandibular disorders (TMD)-related pain and its treatment with analgesic drugs. Temporomandibular disorders are comprised of a group of conditions that result in temporomandibular joint pain (arthralgia, arthritis) and/or masticatory muscle pain (myofascial TMD). In at least some patients with TMD, a peripheral mechanism contributes to this pain. However, there is often a poor correlation between the severity of TMD-related pain complaints and evidence of definitive tissue pathology. This has led to the concept that pain in some patients with TMD may result from altered central nervous system pain processing and further that this altered pain processing may be attributable to specific genes that are heritable. Psychosocial stressors are also thought to contribute to the development of TMD-related pain, particularly masticatory muscle pain. Finally, substantially more women suffer from TMD than men. Although there are arguably multiple reasons for sex-related differences in the prevalence of TMD, one candidate for the increased occurrence of this disorder in women has been suggested to be the female sex hormone oestrogen. Analgesic drugs are an integral part of the primary treatment for TMD-related pain and dysfunction with more that 90% of treatment recommendations involving use of medications. The most commonly used agents include non-steroidal anti-inflammatory drugs, corticosteroids, muscle relaxants, anxiolytics, opiates and tricyclic antidepressants, however, evidence in support of the effectiveness of these drugs is lacking. Continued research into the pathophysiology of TMD-related pain and the effectiveness of analgesic treatments for this pain is required.
Collapse
Affiliation(s)
- B E Cairns
- Canada Research Chair in Neuropharmacology, Faculty of Pharmaceutical Sciences, University of British Columbia, 2146 East Mall, Vancouver, Canada.
| |
Collapse
|
63
|
Nakagawa K, Takeda M, Tsuboi Y, Kondo M, Kitagawa J, Matsumoto S, Kobayashi A, Sessle BJ, Shinoda M, Iwata K. Alteration of primary afferent activity following inferior alveolar nerve transection in rats. Mol Pain 2010; 6:9. [PMID: 20122287 PMCID: PMC2829527 DOI: 10.1186/1744-8069-6-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2009] [Accepted: 02/03/2010] [Indexed: 01/17/2023] Open
Abstract
Background In order to evaluate the neural mechanisms underlying the abnormal facial pain that may develop following regeneration of the injured inferior alveolar nerve (IAN), the properties of the IAN innervated in the mental region were analyzed. Results Fluorogold (FG) injection into the mental region 14 days after IAN transection showed massive labeling of trigeminal ganglion (TG). The escape threshold to mechanical stimulation of the mental skin was significantly lower (i.e. mechanical allodynia) at 11-14 days after IAN transection than before surgery. The background activity, mechanically evoked responses and afterdischarges of IAN Aδ-fibers were significantly higher in IAN-transected rats than naive. The small/medium diameter TG neurons showed an increase in both tetrodotoxin (TTX)-resistant (TTX-R) and -sensitive (TTX-S) sodium currents (INa) and decrease in total potassium current, transient current (IA) and sustained current (IK) in IAN-transected rats. The amplitude, overshoot amplitude and number of action potentials evoked by the depolarizing pulses after 1 μM TTX administration in TG neurons were significantly higher, whereas the threshold current to elicit spikes was smaller in IAN-transected rats than naive. Resting membrane potential was significantly smaller in IAN-transected rats than that of naive. Conclusions These data suggest that the increase in both TTX-S INa and TTX-R INa and the decrease in IA and Ik in small/medium TG neurons in IAN-transected rats are involved in the activation of spike generation, resulting in hyperexcitability of Aδ-IAN fibers innervating the mental region after IAN transection.
Collapse
Affiliation(s)
- Kazuharu Nakagawa
- Department of Dysphagia Rehabilitation, Nihon University School of Dentistry, 1-8-13 Kanda-Surugadai, Chiyoda-ku, Tokyo, 101-8310, Japan
| | | | | | | | | | | | | | | | | | | |
Collapse
|
64
|
Vernon H, Sun K, Zhang Y, Yu XM, Sessle BJ. Central sensitization induced in trigeminal and upper cervical dorsal horn neurons by noxious stimulation of deep cervical paraspinal tissues in rats with minimal surgical trauma. J Manipulative Physiol Ther 2010; 32:506-14. [PMID: 19748401 DOI: 10.1016/j.jmpt.2009.08.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2009] [Revised: 06/22/2009] [Accepted: 06/29/2009] [Indexed: 11/19/2022]
Abstract
OBJECTIVE This study investigated if central sensitization is induced in the trigeminal subnucleus caudalis (also termed the medullary dorsal horn) and C1 and C2 dorsal horns by noxious stimulation of deep upper cervical paraspinal tissues in a preparation relatively free of surgical trauma. METHODS Adult male Sprague-Dawley rats (275-450 g) were anesthetized intraperitoneally. Animals were then placed in a stereotaxic frame; a small cutaneous incision was made 3 to 4 mm near the bregma in the midline, and an opening into the skull was prepared by a 1/32-inch drill, 1 mm to the left from the midline. An epoxylite-coated tungsten microelectrode was introduced at an 18 degrees angle to enter this small opening on the skull and was then carefully advanced about 16 mm through cortex, cerebellum, and brainstem to reach subsequently histologically confirmed sites in the Vc and upper cervical (C1 and C2) dorsal horn region. Thirty-three, 27, and 15 neurons recorded in medullary, C1, and C2 dorsal horns, respectively, of chloralose/urethane-anesthetized rats were activated by noxious stimulation of mechanoreceptive fields involving V1, V2, and/or V3 trigeminal nerve territories. The inflammatory irritant mustard oil was injected into the deep paraspinal tissues at the level of the left C1-C2 joint. Pre and postinjection receptive field (RF) sizes were mapped by nonnoxious mechanical stimuli and noxious mechanical and heat stimuli. RESULTS A 30- to 50-minute increase (mean, 165% +/- 38.1%) in RF size postinjection for 62% of neurons tested was demonstrated, suggesting central sensitization; for most (>70%) neurons, the RF expanded caudally into cervically innervated tissues. CONCLUSIONS These findings provide the first documentation that deep cervical nociceptive inputs can induce central sensitization in medullary and C1/C2 dorsal horns and suggest that these effects may reflect mechanisms contributing to deep cervical pain and its referral.
Collapse
Affiliation(s)
- Howard Vernon
- Canadian Memorial Chiropractic College, Toronto, Ontario, Canada.
| | | | | | | | | |
Collapse
|
65
|
Lam DK, Sessle BJ, Hu JW. Glutamate and capsaicin effects on trigeminal nociception II: Activation and central sensitization in brainstem neurons with deep craniofacial afferent input. Brain Res 2009; 1253:48-59. [DOI: 10.1016/j.brainres.2008.11.056] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2008] [Revised: 11/17/2008] [Accepted: 11/17/2008] [Indexed: 10/21/2022]
|
66
|
Partial infraorbital nerve ligation as a model of trigeminal nerve injury in the mouse: behavioral, neural, and glial reactions. THE JOURNAL OF PAIN 2008; 9:1036-48. [PMID: 18708302 DOI: 10.1016/j.jpain.2008.06.006] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2008] [Revised: 06/05/2008] [Accepted: 06/09/2008] [Indexed: 01/03/2023]
Abstract
UNLABELLED Trigeminal nerve damage often leads to chronic pain syndromes including trigeminal neuralgia, a severely debilitating chronic orofacial pain syndrome. Options for treatment of neuropathic pain are limited in effectiveness and new approaches based on a better understanding of the underlying pathologies are required. Partial ligation has been shown to effectively mimic many of the qualities of human neuropathic pain syndromes. We have devised a mouse model of trigeminal neuralgia using a partial infraorbital nerve ligation (pIONL) that induces persistent pain behaviors and morphological changes in the brainstem. We found that the pIONL effectively induced mechanical allodynia lasting for more than 3 weeks. Cell proliferation (bromodeoxyuridine), activation of astrocytes and microglia in the ipsilateral caudal medulla, and persistent satellite cell reaction in the ipsilateral ganglion were observed. Neurochemical markers calcitonin gene-related peptide, substance P were decreased in medullary dorsal horn ipsilateral to the injury side, whereas substance P receptor NK1 expression was increased after 8 days. Nerve injury marker ATF3 was markedly increased in ipsilateral trigeminal ganglion neurons at 8 days after pIONL. The data indicate that partial trigeminal injury in mice produces many persistent anatomical changes in neuropathic pain, as well as mechanical allodynia. PERSPECTIVE This study describes the development of a new mouse model of trigeminal neuropathic pain. Our goal is to devise better treatments of trigeminal pain, and this will be facilitated by characterization of the underlying cellular and molecular neuropathological mechanisms in genetically designed mice.
Collapse
|
67
|
Furuta A, Kita M, Suzuki Y, Egawa S, Chancellor MB, de Groat WC, Yoshimura N. Association of overactive bladder and stress urinary incontinence in rats with pudendal nerve ligation injury. Am J Physiol Regul Integr Comp Physiol 2008; 294:R1510-6. [PMID: 18337317 DOI: 10.1152/ajpregu.00838.2007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Approximately one-third of patients with stress urinary incontinence (SUI) also suffer from urgency incontinence, which is one of the major symptoms of overactive bladder (OAB) syndrome. Pudendal nerve injury has been recognized as a possible cause for both SUI and OAB. Therefore, we investigated the effects of pudendal nerve ligation (PNL) on bladder function and urinary continence in female Sprague-Dawley rats. Conscious cystometry with or without capsaicin pretreatment (125 mg/kg sc), leak point pressures (LPPs), contractile responses of bladder muscle strips to carbachol or phenylephrine, and levels of nerve growth factor (NGF) protein and mRNA in the bladder were compared in sham and PNL rats 4 wk after the injury. Urinary frequency detected by a reduction in intercontraction intervals and voided volume was observed in PNL rats compared with sham rats, but it was not seen in PNL rats with capsaicin pretreatment that desensitizes C-fiber-afferent pathways. LPPs in PNL rats were significantly decreased compared with sham rats. The contractile responses of detrusor muscle strips to phenylephrine, but not to carbachol, were significantly increased in PNL rats. The levels of NGF protein and mRNA in the bladder of PNL rats were significantly increased compared with sham rats. These results suggest that pudendal nerve neuropathy induced by PNL may be one of the potential risk factors for OAB, as well as SUI. Somato-visceral cross sensitization between somatic (pudendal) and visceral (bladder) sensory pathways that increases NGF expression and alpha(1)-adrenoceptor-mediated contractility in the bladder may be involved in this pathophysiological mechanism.
Collapse
Affiliation(s)
- Akira Furuta
- Department of Urology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213-3221, USA
| | | | | | | | | | | | | |
Collapse
|