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1.
Zhen Ci Yan Jiu ; 45(5): 368-72, 2020 May 25.
Artigo em Chinês | MEDLINE | ID: mdl-32447850

RESUMO

OBJECTIVE: To investigate the effect of electroacupuncture stimulation at "Zusanli"(ST36) and "Kunlun"(BL60) on the morphological changes of the spinal dorsal horn and the expression of p38 mitogen-activated protein kinase (p38MAPK) in the injured spinal cord of rats with neuropathic pain. METHODS: Male Sprague-Dawley rats were randomly divided into sham model group, model group, electroacupuncture group, and medication group, with 10 rats in each group. Spinal nerve ligation of the L5 lumbar vertebra was performed to establish a rat model of neuropathic pain. The rats in the electroacupuncture group were given electroacupuncture at ST36 and BL60 of the operation side with dilatational wave at a frequency of 2 Hz/100 Hz and an intensity of 1.5 mA once a day, 30 minutes each time, and those in the medication group were given intraperitoneal injection of 100 mg/mL Gabapentin solution (100 mg/kg) once a day; the one-week intervention was started at one week after surgery. Mechanical withdraw threshold (MWT) and thermal withdrawal latency (TWL) were observed and recorded before modeling and on days 1,3,5,7,10,12 and 14 after modeling, and the motor function of the affected hindlimb was scored. Methenamine silver stain was used to observe the morphological changes of the spinal dorsal horn, and Western blot was used to measure the relative protein expression of p38MAPK and phospho-p38MAPK(p-p38MAPK) in L4-L6 spinal segments. RESULTS: Compared with the sham model group, the model group had significant reductions in MWT and TWL at each time point (P<0.001) and a significant increase in motor function score (P<0.001); compared with the model group, the electroacupuncture group and the medication group had significant increases in MWT and TWL and a significant reduction in motor function score after treatment (P<0.05). The model group had obvious neuronal fibrillary tangles, particle vacuolar degeneration, and vacuoles containing argyrophilic grains in the cytoplasm of neural cells under a light microscope, while there were fewer neuronal fibrillary tangles in the electroacupuncture group and reduced vacuolar degeneration in the medication group. Compared with the sham model group, the model group had significant increases in the protein expression of p-p38MAPK in the spinal dorsal horn (P<0.001), and compared with the model group, the electroacupuncture group and the medication group had significant reductions in the protein expression of p-p38MAPK in the spinal dorsal horn(P<0.05). CONCLUSION: Electroacupuncture stimulation at ST36 and BL60 can increase pain threshold, improve the motor function of the affected hindlimb, and improve the necrosis of neurofibrils in the spinal dorsal horn in rats with neuropathic pain, possibly by regulating the expression of p-p38MAPK in the spinal dorsal horn.


Assuntos
Eletroacupuntura , Neuralgia , Animais , Masculino , Ratos , Ratos Sprague-Dawley , Corno Dorsal da Medula Espinal , Proteínas Quinases p38 Ativadas por Mitógeno
2.
Xi Bao Yu Fen Zi Mian Yi Xue Za Zhi ; 36(2): 111-116, 2020 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-32314707

RESUMO

Objective To investigate the expression and distribution of spalt-like transcription factor 1 (Sall1) in the lumbar spinal dorsal horn of mice with sciatic nerve branch selective injury. Methods BALB/c mice aged 6~8 weeks old were randomly divided into a control group, a sham operation group and a sciatic nerve branch selective injury group. The mechanical withdrawal threshold (MWT) was measured on the 1st day before the establishment of the model and on the 3rd, 7th, 10th and 14th day after operation. On the 3rd, 7th, 10th and 14th day after operation, the dorsal horn was collected from the L4-6 segments of the affected spinal cord. The expression of Sall1 and the mRNA levels of inflammatory cytokines such as interleukin 1ß (IL-1ß), IL-6 and tumor necrosis factor alpha (TNF-α) on the 7th day after operation were detected by real-time quantitative PCR. The expression of Sall1 protein was determined by Western blot analysis at the above four time points. Immunohistochemical staining and semi-quantitative analysis were performed to analyze the expression and distribution of Sall1 in the spinal cord on the 3rd, 7th, 10th and 14th day after operation. Results Compared with the control group and the sham operation group, MWT of the SNI group decreased on the 3rd, 7th, 10th and 14th day after operation. Compared with the control group, the mRNA and protein levels of Sall1 in SNI group decreased on the 7th, 10th and 14th day after operation. The mRNA levels of IL-1ß, IL-6 and TNF-α increased at 7th day after operation. Sall1 in the control group and SNI group was mainly distributed in the spinal dorsal horn, and the expression in the SNI group was significantly lower than that in the control group at all time points except for the 3th day after operation. Conclusion Sall1 is distributed in the dorsal horn of spinal cord. Sciatic nerve branch selective injury could decrease the expression of Sall1 and increase the expression of IL-1ß, IL-6 and TNF-α mRNA in the dorsal horn of lumbar spinal cord.


Assuntos
Nervo Isquiático/lesões , Corno Dorsal da Medula Espinal/metabolismo , Fatores de Transcrição/metabolismo , Animais , Interleucina-1beta/metabolismo , Interleucina-6/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Distribuição Aleatória , Fator de Necrose Tumoral alfa/metabolismo
3.
Am J Physiol Heart Circ Physiol ; 318(4): H830-H839, 2020 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-32108524

RESUMO

Inherent and acquired factors determine the integrated autonomic response to cardiovascular stressors. Excessive sympathoexcitation to ischemic stress is a major contributor to the potential for sudden cardiac death. To define fundamental aspects of cardiac-related autonomic neural network interactions within the thoracic cord, specifically as related to modulating sympathetic preganglionic (SPN) neural activity. Adult, anesthetized Yorkshire pigs (n = 10) were implanted with penetrating high-density microarrays (64 electrodes) at the T2 level of the thoracic spinal cord to record extracellular potentials concurrently from left-sided dorsal horn (DH) and SPN neurons. Electrical stimulation of the T2 paravertebral chain allowed for antidromic identification of SPNs located in the intermediolateral cell column (57 of total 1,760 recorded neurons). Cardiac stressors included epicardial touch, occlusion of great vessels to transiently alter preload/afterload, and transient occlusion of the left anterior descending coronary artery (LAD). Spatial/temporal assessment of network interactions was characterized by cross-correlation analysis. While some DH neurons responded solely to changes in preload/afterload (8.5 ± 1.9%) or ischemic stress (10.5 ± 3.9%), the majority of cardiovascular-related DH neurons were multimodal (30.2 ± 4.7%) with ischemia sensitivity being one of the modalities (26.1 ± 4.7%). The sympathoexcitation associated with transient LAD occlusion was associated with increased correlations from baseline within DH neurons (2.43 ± 0.61 to 7.30 ± 1.84%, P = 0.04) and between SPN to DH neurons (1.32 ± 0.78 to 7.24 ± 1.84%, P = 0.02). DH to SPN network correlations were reduced during great vessel occlusion. In conclusion, increased intrasegmental network coherence within the thoracic spinal cord contributes to myocardial ischemia-induced sympathoexcitation.NEW & NOTEWORTHY In an in vivo pig model, we demonstrate using novel high-resolution neural electrode arrays that increased intrasegmental network coherence within the thoracic spinal cord contributes to myocardial ischemia-induced sympathoexcitation.


Assuntos
Coração/inervação , Rede Nervosa/fisiologia , Corno Dorsal da Medula Espinal/fisiologia , Sistema Nervoso Simpático/fisiologia , Animais , Fibras Autônomas Pré-Ganglionares/fisiologia , Feminino , Coração/fisiologia , Masculino , Estresse Fisiológico , Suínos
4.
J Oral Sci ; 62(2): 144-146, 2020 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-32101811

RESUMO

Corticofugal projections to neurons in the medullary dorsal horn, i.e., the trigeminal spinal subnucleus caudalis (Sp5C), are thought to play a critical role in regulating nociceptive information processing in the trigeminal nervous system. The Sp5C consists of 5 layers, each of which exhibits its own characteristic features of cellular organization. Therefore, the layers receiving corticofugal projections must be identified when discussing the role of the cerebral cortex in nociception arising from the trigeminal nerve. It is also necessary to discriminate between layers of the Sp5C where corticofugal projections terminate, because the Sp5C involves glutamatergic neurons and GABAergic/glycinergic neurons, which correspond to excitatory and inhibitory neurons, respectively. This review summarizes descending projections from the cerebral cortex, including the primary and secondary somatosensory and insular cortices, to the Sp5C.


Assuntos
Córtex Cerebral , Corno Dorsal da Medula Espinal , Animais , Neurônios , Nociceptividade , Ratos , Ratos Sprague-Dawley
5.
PLoS One ; 15(2): e0226289, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32015563

RESUMO

Calcium binding proteins are expressed throughout the central and peripheral nervous system and disruption of their activity has major consequences in a wide array of cellular processes, including transmission of nociceptive signals that are processed at the level of the spinal cord. We previously reported that the calcium binding protein, hippocalcin-like 4 (Hpcal4), is heavily expressed in interneurons of the superficial dorsal horn, and that its expression is significantly downregulated in a TR4 mutant mouse model that exhibits major pain and itch deficits due to loss of a subpopulation of excitatory interneurons. That finding suggested that Hpcal4 may be a contributor to the behavioral phenotype of the TR4 mutant mouse. To address this question, here we investigated the behavioral consequences of global deletion of Hpcal4 in a battery of acute and persistent pain and itch tests. Unexpectedly, with the exception of a mild reduction in acute baseline thermal responses, Hpcal4-deficient mice exhibit no major deficits in pain or itch responses, under normal conditions or in the setting of tissue or nerve injury. Taken together, our results indicate that the neural calcium sensor Hpcal4 likely makes a limited contribution to pain and itch processing.


Assuntos
Neurocalcina/metabolismo , Dor/metabolismo , Prurido/metabolismo , Animais , Escala de Avaliação Comportamental , Comportamento Animal , Cloroquina/administração & dosagem , Cloroquina/farmacologia , Técnicas de Inativação de Genes , Histamina/administração & dosagem , Histamina/farmacologia , Temperatura Alta , Interneurônios/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Neurocalcina/genética , Prurido/induzido quimicamente , Nervo Isquiático/lesões , Corno Dorsal da Medula Espinal/metabolismo
6.
PLoS One ; 15(1): e0228134, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31990932

RESUMO

Chronic lameness affects bovine welfare and has a negative economic impact in dairy industry. Moreover, due to the translational gap between traditional pain models and new drugs development for treating chronic pain states, naturally occurring painful diseases could be a potential translational tool for chronic pain research. We therefore employed liquid chromatography tandem mass spectrometry (LC-MS/MS) to stablish the proteomic profile of the spinal cord samples from lumbar segments (L2-L4) of chronic lame dairy cows. Data were validated and quantified through software tool (Scaffold® v 4.0) using output data from two search engines (SEQUEST® and X-Tandem®). Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) analysis was performed to detect proteins interactions. LC-MS/MS identified a total amount of 177 proteins; of which 129 proteins were able to be quantified. Lame cows showed a strong upregulation of interacting proteins with chaperone and stress functions such as Hsp70 (p < 0.006), Hsc70 (p < 0.0079), Hsp90 (p < 0.015), STIP (p > 0.0018) and Grp78 (p <0.0068), and interacting proteins associated to glycolytic pathway such as; γ-enolase (p < 0.0095), α-enolase (p < 0.013) and hexokinase-1 (p < 0.028). It was not possible to establish a clear network of interaction in several upregulated proteins in lame cows. Non-interacting proteins were mainly associated to redox process and cytoskeletal organization. The most relevant down regulated protein in lame cows was myelin basic protein (MBP) (p < 0.02). Chronic inflammatory lameness in cows is associated to increased expression of stress proteins with chaperone, metabolism, redox and structural functions. A state of endoplasmic reticulum stress and unfolded protein response (UPR) might explain the changes in protein expression in lame cows; however, further studies need to be performed in order to confirm these findings.


Assuntos
Doenças dos Bovinos/genética , Dor Crônica/veterinária , Regulação da Expressão Gênica , Coxeadura Animal/genética , Proteína Básica da Mielina/genética , Proteínas do Tecido Nervoso/genética , Animais , Bovinos , Doenças dos Bovinos/metabolismo , Doenças dos Bovinos/fisiopatologia , Dor Crônica/genética , Dor Crônica/metabolismo , Dor Crônica/fisiopatologia , Indústria de Laticínios , Feminino , Perfilação da Expressão Gênica , Ontologia Genética , Redes Reguladoras de Genes , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/metabolismo , Isoenzimas/genética , Isoenzimas/metabolismo , Lactação/fisiologia , Coxeadura Animal/metabolismo , Coxeadura Animal/fisiopatologia , Anotação de Sequência Molecular , Proteína Básica da Mielina/metabolismo , Proteínas do Tecido Nervoso/classificação , Proteínas do Tecido Nervoso/metabolismo , Fosfopiruvato Hidratase/genética , Fosfopiruvato Hidratase/metabolismo , Proteômica/métodos , Corno Dorsal da Medula Espinal/metabolismo , Corno Dorsal da Medula Espinal/fisiopatologia
7.
J Orthop Res ; 38(2): 422-430, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31538672

RESUMO

We investigated the efficacy of duloxetine on hyperalgesia, histopathological and radiographic findings, pain-related sensory innervation of dorsal-root ganglia (DRG), and spinal changes in a rat model of induced hip osteoarthritis (OA). The right hip joints of male Sprague-Dawley rats (n = 6 rats/group) in the Sham group were injected with 25 µl of sterile saline and 25 µl of sterile saline with 2 mg of monosodium iodoacetate (MIA) were injected to the MIA + Vehicle and MIA + Duloxetine groups. We injected duloxetine 20 mg/kg intraperitoneally in the MIA + Duloxetine group 28 days after injection, whereas rats in the MIA + Vehicle group were injected with 0.5 ml of 20% dimethyl sulfoxide. We assessed hyperalgesia, histopathological changes, immunoreactive (-ir) neurons for calcitonin gene-related peptide and activating transcription factor 3 in DRG, and immunoreactive neurons for ionized-calcium-binding adaptor molecule 1 (Iba1) in the dorsal horn of the spinal cord. MIA administration into the hip joint let to mechanical hyperalgesia of the ipsilateral hind paw (p < 0.05). A single injection of duloxetine significantly attenuated it in induced hip OA (p < 0.05) and suppressed the number of Iba1-ir microglia of the ipsilateral dorsal horn (p < 0.05). These results suggest that a single injection of duloxetine suppressed mechanical hyperalgesia and may influence the expression of Iba1 in the microglia of the ipsilateral dorsal horn in the MIA-induced hip OA. This finding implies the inhibitory effects of duloxetine against neuropathic pain, which may lead to a change of microglial activities. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:422-430, 2020.


Assuntos
Analgésicos/uso terapêutico , Cloridrato de Duloxetina/uso terapêutico , Articulação do Quadril/efeitos dos fármacos , Osteoartrite do Quadril/tratamento farmacológico , Analgésicos/farmacologia , Animais , Peptídeo Relacionado com Gene de Calcitonina/metabolismo , Modelos Animais de Doenças , Avaliação Pré-Clínica de Medicamentos , Cloridrato de Duloxetina/farmacologia , Gânglios Espinais/efeitos dos fármacos , Gânglios Espinais/metabolismo , Articulação do Quadril/diagnóstico por imagem , Articulação do Quadril/patologia , Ácido Iodoacético , Masculino , Osteoartrite do Quadril/induzido quimicamente , Osteoartrite do Quadril/diagnóstico por imagem , Osteoartrite do Quadril/patologia , Ratos Sprague-Dawley , Corno Dorsal da Medula Espinal/efeitos dos fármacos , Corno Dorsal da Medula Espinal/metabolismo
8.
Biosci Biotechnol Biochem ; 84(1): 159-170, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31483212

RESUMO

We tested whether Sake Lees (SL) had inhibitory effects on hyperalgesia in the hindpaw under psychophysical stress conditions. Male rats were subjected to repeated forced swim stress treatments (FST) from Day -3 to Day -1. Intraperiotoneal administration of SL which contained low concentration of ethanol (SLX) was conducted after each FST. On Day 0, formalin-evoked licking behaviors and Fos responses in the lumbar spinal cord (DH) and several areas within the rostral ventromedial medulla (RVM) were quantified as nociceptive responses. FST-induced hyperalgesia in the hindpaw was prevented by repeated SL and SLX treatments. Fos expression was significantly increased in DH and some areas within the RVM under FST, which was prevented by repeated SL or SLX. These findings indicated that daily administration of SL had the potential to alleviate stress-induced hyperalgesia.


Assuntos
Fermentação , Membro Posterior/metabolismo , Hiperalgesia/tratamento farmacológico , Oryza/química , Extratos Vegetais/farmacologia , Proteínas Proto-Oncogênicas c-fos/metabolismo , Corno Dorsal da Medula Espinal/metabolismo , Estresse Fisiológico/fisiologia , Animais , Comportamento Animal/efeitos dos fármacos , Etanol/química , Formaldeído/administração & dosagem , Formaldeído/farmacologia , Hiperalgesia/etiologia , Imuno-Histoquímica , Masculino , Manejo da Dor , Medição da Dor , Extratos Vegetais/administração & dosagem , Proteínas Proto-Oncogênicas c-fos/imunologia , Ratos , Ratos Sprague-Dawley , Neurônios Serotoninérgicos/efeitos dos fármacos , Neurônios Serotoninérgicos/metabolismo , Serotonina/imunologia , Serotonina/metabolismo , Natação/fisiologia , Distribuição Tecidual
9.
Elife ; 82019 11 12.
Artigo em Inglês | MEDLINE | ID: mdl-31713514

RESUMO

Nociceptive information is relayed through the spinal cord dorsal horn, a critical area in sensory processing. The neuronal circuits in this region that underpin sensory perception must be clarified to better understand how dysfunction can lead to pathological pain. This study used an optogenetic approach to selectively activate spinal interneurons that express the calcium-binding protein calretinin (CR). We show that these interneurons form an interconnected network that can initiate and sustain enhanced excitatory signaling, and directly relay signals to lamina I projection neurons. Photoactivation of CR interneurons in vivo resulted in a significant nocifensive behavior that was morphine sensitive, caused a conditioned place aversion, and was enhanced by spared nerve injury. Furthermore, halorhodopsin-mediated inhibition of these interneurons elevated sensory thresholds. Our results suggest that dorsal horn circuits that involve excitatory CR neurons are important for the generation and amplification of pain and identify these interneurons as a future analgesic target.


Assuntos
Calbindina 2/genética , Interneurônios/metabolismo , Neuralgia/fisiopatologia , Neurônios/metabolismo , Corno Dorsal da Medula Espinal/metabolismo , Analgésicos Opioides/farmacologia , Animais , Calbindina 2/metabolismo , Modelos Animais de Doenças , Expressão Gênica , Halorrodopsinas/genética , Halorrodopsinas/metabolismo , Interneurônios/efeitos dos fármacos , Interneurônios/patologia , Camundongos , Camundongos Transgênicos , Morfina/farmacologia , Rede Nervosa/efeitos dos fármacos , Rede Nervosa/metabolismo , Rede Nervosa/patologia , Neuralgia/tratamento farmacológico , Neuralgia/genética , Neuralgia/metabolismo , Neurônios/efeitos dos fármacos , Neurônios/patologia , Optogenética/métodos , Limiar da Dor/efeitos dos fármacos , Técnicas de Patch-Clamp , Estimulação Luminosa , Corno Dorsal da Medula Espinal/efeitos dos fármacos , Corno Dorsal da Medula Espinal/patologia , Técnicas de Cultura de Tecidos , Transgenes
10.
J Neuroinflammation ; 16(1): 207, 2019 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-31703709

RESUMO

BACKGROUND: Neuropathic pain is often observed in individuals with multiple sclerosis (MS) and spinal cord injury (SCI) and is not adequately alleviated by current pharmacotherapies. A better understanding of underlying mechanisms could facilitate the discovery of novel targets for therapeutic interventions. We previously reported that decreased plasma membrane calcium ATPase 2 (PMCA2) expression in the dorsal horn (DH) of healthy PMCA2+/- mice is paralleled by increased sensitivity to evoked nociceptive pain. These studies suggested that PMCA2, a calcium extrusion pump expressed in spinal cord neurons, plays a role in pain mechanisms. However, the contribution of PMCA2 to neuropathic pain processing remains undefined. The present studies investigated the role of PMCA2 in neuropathic pain processing in the DH of wild-type mice affected by experimental autoimmune encephalomyelitis (EAE), an animal model of MS, and following SCI. METHODS: EAE was induced in female and male C57Bl/6N mice via inoculation with myelin oligodendrocyte glycoprotein fragment 35-55 (MOG35-55) emulsified in Complete Freund's Adjuvant (CFA). CFA-inoculated mice were used as controls. A severe SC contusion injury was induced at thoracic (T8) level in female C57Bl/6N mice. Pain was evaluated by the Hargreaves and von Frey filament tests. PMCA2 levels in the lumbar DH were analyzed by Western blotting. The effectors that decrease PMCA2 expression were identified in SC neuronal cultures. RESULTS: Increased pain in EAE and SCI was paralleled by a significant decrease in PMCA2 levels in the DH. In contrast, PMCA2 levels remained unaltered in the DH of mice with EAE that manifested motor deficits but not increased pain. Interleukin-1ß (IL-1ß), tumor necrosis factor α (TNFα), and IL-6 expression were robustly increased in the DH of mice with EAE manifesting pain, whereas these cytokines showed a modest increase or no change in mice with EAE in the absence of pain. Only IL-1ß decreased PMCA2 levels in pure SC neuronal cultures through direct actions. CONCLUSIONS: PMCA2 is a contributor to neuropathic pain mechanisms in the DH. A decrease in PMCA2 in DH neurons is paralleled by increased pain sensitivity, most likely through perturbations in calcium signaling. Interleukin-1ß is one of the effectors that downregulates PMCA2 by acting directly on neurons.


Assuntos
Encefalomielite Autoimune Experimental/metabolismo , Neuralgia/metabolismo , ATPases Transportadoras de Cálcio da Membrana Plasmática/metabolismo , Traumatismos da Medula Espinal/metabolismo , Animais , Modelos Animais de Doenças , Feminino , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Esclerose Múltipla/metabolismo , Percepção da Dor/fisiologia , Corno Dorsal da Medula Espinal/metabolismo
11.
Elife ; 82019 11 19.
Artigo em Inglês | MEDLINE | ID: mdl-31742556

RESUMO

Neuropathic pain is a debilitating condition caused by the abnormal processing of somatosensory input. Synaptic inhibition in the spinal dorsal horn plays a key role in that processing. Mechanical allodynia - the misperception of light touch as painful - occurs when inhibition is compromised. Disinhibition is due primarily to chloride dysregulation caused by hypofunction of the potassium-chloride co-transporter KCC2. Here we show, in rats, that excitatory neurons are disproportionately affected. This is not because chloride is differentially dysregulated in excitatory and inhibitory neurons, but, rather, because excitatory neurons rely more heavily on inhibition to counterbalance strong excitation. Receptive fields in both cell types have a center-surround organization but disinhibition unmasks more excitatory input to excitatory neurons. Differences in intrinsic excitability also affect how chloride dysregulation affects spiking. These results deepen understanding of how excitation and inhibition are normally balanced in the spinal dorsal horn, and how their imbalance disrupts somatosensory processing.


Assuntos
Cloretos/metabolismo , Neurônios/metabolismo , Corno Dorsal da Medula Espinal/metabolismo , Animais , Feminino , Hiperalgesia/metabolismo , Masculino , Modelos Animais , Modelos Biológicos , Fenômenos Fisiológicos do Sistema Nervoso , Neuralgia/metabolismo , Ratos , Ratos Sprague-Dawley , Medula Espinal/metabolismo , Simportadores/metabolismo
12.
Int J Mol Sci ; 20(20)2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31618823

RESUMO

Persistent post-surgical pain (PPSP) is a chronic pain condition, often with neuropathic features, that occurs in approximately 20% of children who undergo surgery. The biological basis of PPSP has not been elucidated. Anesthetic drugs can have lasting effects on the developing nervous system, although the clinical impact of this phenomenon is unknown. Here, we used a mouse model to test the hypothesis that early developmental exposure to isoflurane causes cellular and molecular alteration in the pain perception circuitry that causes a predisposition to chronic, neuropathic pain via a pathologic upregulation of the mammalian target of the rapamycin (mTOR) signaling pathway. Mice were exposed to isoflurane at postnatal day 7 and select cohorts were treated with rapamycin, an mTOR pathway inhibitor. Behavioral tests conducted 2 months later showed increased evidence of neuropathic pain, which did not occur in rapamycin-treated animals. Immunohistochemistry showed neuronal activity was chronically increased in the insular cortex, anterior cingulate cortex, and spinal dorsal horn, and activity was attenuated by rapamycin. Immunohistochemistry and western blotting (WB) showed a co-incident chronic, abnormal upregulation in mTOR activity. We conclude that early isoflurane exposure alters the development of pain circuits and has the potential to contribute to PPSP and/or other pain syndromes.


Assuntos
Dor Crônica/etiologia , Dor Crônica/metabolismo , Isoflurano/farmacologia , Transdução de Sinais/efeitos dos fármacos , Serina-Treonina Quinases TOR/metabolismo , Animais , Biomarcadores , Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/metabolismo , Dor Crônica/diagnóstico , Dor Crônica/tratamento farmacológico , Imuno-Histoquímica , Camundongos , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Proteínas Quinases S6 Ribossômicas/genética , Proteínas Quinases S6 Ribossômicas/metabolismo , Corno Dorsal da Medula Espinal/efeitos dos fármacos , Corno Dorsal da Medula Espinal/metabolismo
13.
Curr Neuropharmacol ; 17(12): 1133-1145, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31573888

RESUMO

BACKGROUND: Despite the extensive number of studies performed in the last 50 years, aimed at describing the role of serotonin and its receptors in pain modulation at the spinal cord level, several aspects are still not entirely understood. The interpretation of these results is often complicated by the use of different pain models and animal species, together with the lack of highly selective agonists and antagonists binding to serotonin receptors. METHOD: In this review, a search has been conducted on studies investigating the modulatory action exerted by serotonin on specific neurons and circuits in the spinal cord dorsal horn. Particular attention has been paid to studies employing electrophysiological techniques, both in vivo and in vitro. CONCLUSION: The effects of serotonin on pain transmission in dorsal horn depend on several factors, including the type of receptors activated and the populations of neurons involved. Recently, studies performed by activating and/or recording from identified neurons have importantly contributed to the understanding of serotonergic modulation on dorsal horn circuits.


Assuntos
Dor Nociceptiva/metabolismo , Serotonina/metabolismo , Corno Dorsal da Medula Espinal/metabolismo , Animais , Humanos , Vias Neurais/metabolismo
14.
Proc Natl Acad Sci U S A ; 116(40): 20201-20209, 2019 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-31530723

RESUMO

Action potential-induced vesicular exocytosis is considered exclusively Ca2+ dependent in Katz's Ca2+ hypothesis on synaptic transmission. This long-standing concept gets an exception following the discovery of Ca2+-independent but voltage-dependent secretion (CiVDS) and its molecular mechanisms in dorsal root ganglion sensory neurons. However, whether CiVDS presents only in sensory cells remains elusive. Here, by combining multiple independent recordings, we report that [1] CiVDS robustly presents in the sympathetic nervous system, including sympathetic superior cervical ganglion neurons and slice adrenal chromaffin cells, [2] uses voltage sensors of Ca2+ channels (N-type and novel L-type), and [3] contributes to catecholamine release in both homeostatic and fight-or-flight like states; [4] CiVDS-mediated catecholamine release is faster than that of Ca2+-dependent secretion at the quantal level and [5] increases Ca2+ currents and contractility of cardiac myocytes. Together, CiVDS presents in the sympathetic nervous system with potential physiological functions, including cardiac muscle contractility.


Assuntos
Cálcio/metabolismo , Catecolaminas/metabolismo , Células Cromafins/metabolismo , Sistema Nervoso Simpático/metabolismo , Potenciais de Ação , Animais , Mamíferos , Modelos Biológicos , Células Musculares/metabolismo , Neurônios/metabolismo , Corno Dorsal da Medula Espinal/citologia , Corno Dorsal da Medula Espinal/metabolismo , Transmissão Sináptica
15.
eNeuro ; 6(5)2019.
Artigo em Inglês | MEDLINE | ID: mdl-31533959

RESUMO

The spinal dorsal horn is the first relay structure coding for pain transmission and modulation. Previous anatomical and electrophysiological studies have examined spinal dorsal horn circuit connections and network activity. Further work is required to understand spinal cord sensory information processing that underlies pathological neuropathic pain states. Our previous studies suggest that peripheral nerve injury enhances presynaptic excitatory input onto spinal superficial dorsal horn neurons, which in turn contributes to pathologic nociception. The potential changes in local postsynaptic circuits in the dorsal horn that lead to pathologically heightened behavioral responses to pain remain largely unexplored. We combined whole-cell electrophysiological recordings with laser-scanning photostimulation to test whether peripheral nerve injury in the spinal nerve ligation (SNL) mouse model of neuropathic pain leads to alterations in the functional connectivity of spinal cord circuits including lamina II excitatory interneurons. Here we show that SNL enhances excitation and decreases inhibition to lamina II excitatory interneurons along with their increased glutamate-evoked excitability. The enhanced excitatory postsynaptic input and connectivity evoked by SNL eventually return to normal levels concurrently with the resolution of the neuropathic pain states. The physiological pattern highly correlates with mouse pain behaviors following SNL, supporting a neurophysiological mechanism of central sensitization and neuropathic pain that is functionally localized to the spinal dorsal horn. Together, these data support that SNL induces functional changes in synaptic input and connectivity to lamina II excitatory interneurons that code for pain perception, and thus provide new insights into the mechanism and locus of pain hypersensitivity.


Assuntos
Potenciais Pós-Sinápticos Excitadores/fisiologia , Potenciais Pós-Sinápticos Inibidores/fisiologia , Rede Nervosa/fisiopatologia , Neuralgia/fisiopatologia , Plasticidade Neuronal/fisiologia , Corno Dorsal da Medula Espinal/fisiopatologia , Animais , Masculino , Camundongos , Camundongos Transgênicos , Técnicas de Cultura de Órgãos , Medição da Dor/métodos
16.
PLoS One ; 14(9): e0222066, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31498817

RESUMO

Of the fast ionotropic synapses, glycinergic synapses are the least well understood, but are vital for the maintenance of inhibitory signaling in the brain and spinal cord. Glycinergic signaling comprises half of the inhibitory signaling in the spinal cord, and glycinergic synapses are likely to regulate local nociceptive processing as well as the transmission to the brain of peripheral nociceptive information. Here we have investigated the rapid and prolonged potentiation of glycinergic synapses in the superficial dorsal horn of young male and female mice after brief activation of NMDA receptors (NMDARs). Glycinergic inhibitory postsynaptic currents (IPSCs) evoked with lamina II-III stimulation in identified GABAergic neurons in lamina II were potentiated by bath-applied Zn2+ and were depressed by the prostaglandin PGE2, consistent with the presence of both GlyRα1- and GlyRα3-containing receptors. NMDA application rapidly potentiated synaptic glycinergic currents. Whole-cell currents evoked by exogenous glycine were also readily potentiated by NMDA, indicating that the potentiation results from altered numbers or conductance of postsynaptic glycine receptors. Repetitive depolarization alone of the postsynaptic GABAergic neuron also potentiated glycinergic synapses, and intracellular EGTA prevented both NMDA-induced and depolarization-induced potentiation of glycinergic IPSCs. Optogenetic activation of trpv1 lineage afferents also triggered NMDAR-dependent potentiation of glycinergic synapses. Our results suggest that during peripheral injury or inflammation, nociceptor firing during injury is likely to potentiate glycinergic synapses on GABAergic neurons. This disinhibition mechanism may be engaged rapidly, altering dorsal horn circuitry to promote the transmission of nociceptive information to the brain.


Assuntos
Glicina/metabolismo , Potenciação de Longa Duração , Receptores de N-Metil-D-Aspartato/metabolismo , Sinapses/fisiologia , Animais , Cálcio/metabolismo , Feminino , Potenciais Pós-Sinápticos Inibidores , Masculino , Camundongos , Nociceptividade/fisiologia , Receptores da Glicina/metabolismo , Corno Dorsal da Medula Espinal/citologia , Corno Dorsal da Medula Espinal/fisiologia , Sinapses/metabolismo
17.
Nat Commun ; 10(1): 4119, 2019 09 11.
Artigo em Inglês | MEDLINE | ID: mdl-31511520

RESUMO

Circular RNAs are non-coding RNAs, and are enriched in the CNS. Dorsal horn neurons of the spinal cord contribute to pain-like hypersensitivity after nerve injury in rodents. Here we show that spinal nerve ligation is associated with an increase in expression of circAnks1a in dorsal horn neurons, in both the cytoplasm and the nucleus. Downregulation of circAnks1a by siRNA attenuates pain-like behaviour induced by nerve injury. In the cytoplasm, we show that circAnks1a promotes the interaction between transcription factor YBX1 and transportin-1, thus facilitating the nucleus translocation of YBX1. In the nucleus, circAnks1a binds directly to the Vegfb promoter, increases YBX1 recruitment to the Vegfb promoter, thereby facilitating transcription. Furthermore, cytoplasmic circAnks1a acts as a miRNA sponge in miR-324-3p-mediated posttranscriptional regulation of VEGFB expression. The upregulation of VEGFB contributes to increased excitability of dorsal horn neurons and pain behaviour induced by nerve injury. We propose that circAnks1a and VEGFB are regulators of neuropathic pain.


Assuntos
Hipersensibilidade/metabolismo , Neuralgia/genética , Neuralgia/metabolismo , RNA Circular/genética , Medula Espinal/metabolismo , Animais , Sequência de Bases , Núcleo Celular/metabolismo , Proteínas de Ligação a DNA/metabolismo , Modelos Animais de Doenças , Masculino , Camundongos Endogâmicos C57BL , MicroRNAs/metabolismo , Neurônios/metabolismo , Regiões Promotoras Genéticas/genética , Ligação Proteica , Transporte Proteico , Ratos Sprague-Dawley , Roedores , Corno Dorsal da Medula Espinal/metabolismo , Regulação para Cima/genética , Fator B de Crescimento do Endotélio Vascular/metabolismo
18.
PLoS Biol ; 17(8): e3000371, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31433808

RESUMO

Inhibitory glycinergic transmission in adult spinal cord is primarily mediated by glycine receptors (GlyRs) containing the α1 subunit. Here, we found that α1ins, a longer α1 variant with 8 amino acids inserted into the intracellular large loop (IL) between transmembrane (TM)3 and TM4 domains, was expressed in the dorsal horn of the spinal cord, distributed at inhibitory synapses, and engaged in negative control over nociceptive signal transduction. Activation of metabotropic glutamate receptor 5 (mGluR5) specifically suppressed α1ins-mediated glycinergic transmission and evoked pain sensitization. Extracellular signal-regulated kinase (ERK) was critical for mGluR5 to inhibit α1ins. By binding to a D-docking site created by the 8-amino-acid insert within the TM3-TM4 loop of α1ins, the active ERK catalyzed α1ins phosphorylation at Ser380, which favored α1ins ubiquitination at Lys379 and led to α1ins endocytosis. Disruption of ERK interaction with α1ins blocked Ser380 phosphorylation, potentiated glycinergic synaptic currents, and alleviated inflammatory and neuropathic pain. These data thus unraveled a novel, to our knowledge, mechanism for the activity-dependent regulation of glycinergic neurotransmission.


Assuntos
Células do Corno Posterior/metabolismo , Receptores da Glicina/metabolismo , Animais , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Glicina/metabolismo , Sistema de Sinalização das MAP Quinases/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Proteína Quinase 7 Ativada por Mitógeno/metabolismo , Fosforilação , Receptor de Glutamato Metabotrópico 5/metabolismo , Receptor de Glutamato Metabotrópico 5/fisiologia , Receptores da Glicina/fisiologia , Transdução de Sinais/fisiologia , Medula Espinal/metabolismo , Corno Dorsal da Medula Espinal/metabolismo , Coluna Vertebral/metabolismo , Sinapses/metabolismo , Transmissão Sináptica/fisiologia
19.
Purinergic Signal ; 15(3): 403-420, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31444738

RESUMO

Human embryonic kidney 293 (HEK293) cells stably transfected with the rat P2X2 receptor subunit were preincubated with 200 nM progesterone (HEK293-P2X2-PROG), a potent positive allosteric modulator of homomeric P2X2 receptors, and used to detect low nanomolar concentrations of extracellular ATP. Fura-2-loaded HEK293-P2X2-PROG cells were acutely plated on top of cultured DH glial cells to quantify ATP release from single DH glial cells. Application of the α1 adrenoceptor agonist phenylephrine (PHE, 20 µM) or of a low K+ (0.2 mM) solution evoked reversible increases in the intracellular calcium concentration ([Ca2+]i) in the biosensor cells. A reversible increase in [Ca2+]i was also detected in half of the biosensor cells following the interruption of general extracellular perfusion. All increases in [Ca2+]i were blocked in the presence of the P2X2 antagonist PPADS or after preloading the glial cells with the calcium chelator BAPTA, indicating that they were due to calcium-dependent ATP release from the glial cells. ATP release induced by PHE was blocked by -L-phenylalanine 2-naphtylamide (GPN) that permeabilizes secretory lysosomes and bafilomycin A1 (Baf A1), an inhibitor of the H+-pump of acidic secretory vesicles. By contrast, ATP release induced by application of a low-K+ solution was abolished by Baf A1 but not by GPN. Finally, spontaneous ATP release observed after interrupting general perfusion was insensitive to both GPN and Baf A1 pretreatment. Our results indicate that ATP is released in a calcium-dependent manner from two distinct vesicular pools and one non-vesicular pool coexisting in DH glial cells and that noradrenaline and PHE selectively target the secretory lysosome pool.


Assuntos
Trifosfato de Adenosina/análise , Trifosfato de Adenosina/metabolismo , Técnicas Biossensoriais/métodos , Neuroglia/metabolismo , Norepinefrina/farmacologia , Animais , Células HEK293 , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Neuroglia/efeitos dos fármacos , Ratos , Corno Dorsal da Medula Espinal/efeitos dos fármacos , Corno Dorsal da Medula Espinal/metabolismo
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