Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.850
Filtrar
1.
Eur J Med Chem ; 186: 111902, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31771828

RESUMO

We recently identified novel small-molecule antagonists of the PACAP type I (PAC1) receptor using docking-based in silico screening followed by in vitro/vivo pharmacological assays. In the present study, we synthesized 18 novel derivatives based on the structure of PA-9, a recently developed antagonist of the PAC1 receptor, with a view to obtain a panel of compounds with more potent antagonistic and analgesic activities. Among them, compound 3d showed improved antagonistic activities. Intrathecal injection of 3d inhibited both pituitary adenylate cyclase-activating polypeptide (PACAP) and spinal nerve ligation-induced mechanical allodynia. The effects were more potent than PA-9. Compound 3d also showed anti-allodynic effects following oral administration. Hence, our results suggest that 3d may become an orally available analgesic in the treatment of the neuropathic pain.


Assuntos
Analgésicos/farmacologia , Neuralgia/tratamento farmacológico , Receptores de Polipeptídeo Hipofisário Ativador de Adenilato Ciclase/antagonistas & inibidores , Bibliotecas de Moléculas Pequenas/farmacologia , Analgésicos/síntese química , Analgésicos/química , Animais , Comportamento Animal/efeitos dos fármacos , Relação Dose-Resposta a Droga , Masculino , Camundongos , Camundongos Endogâmicos , Estrutura Molecular , Neuralgia/metabolismo , Receptores de Polipeptídeo Hipofisário Ativador de Adenilato Ciclase/metabolismo , Bibliotecas de Moléculas Pequenas/síntese química , Bibliotecas de Moléculas Pequenas/química , Relação Estrutura-Atividade
2.
Braz J Med Biol Res ; 52(10): e8380, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31531524

RESUMO

The present study aimed to identify microRNAs (miRNAs) that are involved in neuropathic pain and predict their corresponding roles in the pathogenesis and development process of neuropathic pain. The rat model of neuropathic pain caused by spared nerve injury (SNI) was established in Sprague-Dawley male rats, followed by small RNA sequencing of the L3-L6 dorsal root ganglion. Real-time PCR was performed to validate the differently expressed miRNAs. Functional verification was performed by intrathecally injecting the animals with miRNA agomir. A total of 72 differentially expressed miRNAs were identified in the SNI rats, including 33 upregulated and 39 downregulated miRNAs. The results of qPCR further verified the expression levels of rno-miR-6215 (P=0.015), rno-miR-1224 (P=0.030), rno-miR-1249 (P=0.038), and rno-miR-488-3p (P=0.048), which were all significantly downregulated in the SNI rats compared to the control ones. The majority of differentially expressed miRNAs were associated with phosphorylation, intracellular signal transduction, and cell death. Target prediction, Gene Ontology, and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses suggested that these differentially expressed miRNAs targeted genes that are related to axon guidance, focal adhesion, and Ras and Wnt signaling pathways. Moreover, miR-1224 agomir significantly alleviated SNI-induced neuropathic pain. The current findings provide new insights into the role of miRNAs in the pathogenesis of neuropathic pain.


Assuntos
MicroRNAs/genética , Neuralgia/genética , Análise de Sequência de RNA , Animais , Sequência de Bases , Modelos Animais de Doenças , Masculino , MicroRNAs/metabolismo , Neuralgia/metabolismo , Ratos , Ratos Sprague-Dawley , Reação em Cadeia da Polimerase em Tempo Real , Transdução de Sinais
3.
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 , 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
4.
Int J Mol Sci ; 20(18)2019 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-31489921

RESUMO

The amygdala plays a key role in emotional-affective aspects of pain and in pain modulation. The central nucleus (CeA) serves major amygdala output functions related to emotional-affective behaviors and pain modulation. Our previous studies implicated the corticotropin-releasing factor (CRF) system in amygdala plasticity and pain behaviors in an arthritis model. We also showed that serotonin (5-HT) receptor subtype 5-HT2CR in the basolateral amygdala (BLA) contributes to increased CeA output and neuropathic pain-like behaviors. Here, we tested the novel hypothesis that 5-HT2CR in the BLA drives CRF1 receptor activation to increase CeA neuronal activity in neuropathic pain. Extracellular single-unit recordings of CeA neurons in anesthetized adult male rats detected increased activity in neuropathic rats (spinal nerve ligation model) compared to sham controls. Increased CeA activity was blocked by local knockdown or pharmacological blockade of 5-HT2CR in the BLA, using stereotaxic administration of 5-HT2CR short hairpin RNA (shRNA) viral vector or a 5-HT2CR antagonist (SB242084), respectively. Stereotaxic administration of a CRF1 receptor antagonist (NBI27914) into the BLA also decreased CeA activity in neuropathic rats and blocked the facilitatory effects of a 5-HT2CR agonist (WAY161503) administered stereotaxically into the BLA. Conversely, local (BLA) knockdown of 5-HT2CR eliminated the inhibitory effect of NBI27914 and the facilitatory effect of WAY161503 in neuropathic rats. The data suggest that 5-HT2CR activation in the BLA contributes to neuropathic pain-related amygdala (CeA) activity by engaging CRF1 receptor signaling.


Assuntos
Tonsila do Cerebelo/metabolismo , Neuralgia/etiologia , Neuralgia/metabolismo , Neurônios/metabolismo , Receptor 5-HT2C de Serotonina/genética , Receptores de Hormônio Liberador da Corticotropina/genética , Tonsila do Cerebelo/fisiopatologia , Animais , Modelos Animais de Doenças , Técnicas de Silenciamento de Genes , Masculino , Neuralgia/fisiopatologia , Ratos , Receptor 5-HT2C de Serotonina/metabolismo , Receptores de Hormônio Liberador da Corticotropina/antagonistas & inibidores , Receptores de Hormônio Liberador da Corticotropina/metabolismo , Antagonistas do Receptor 5-HT2 de Serotonina/farmacologia
5.
Neurochem Res ; 44(9): 2123-2138, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31376053

RESUMO

Number of ligations made in the chronic constriction injury (CCI) neuropathic pain model has raised serious concerns. We compared behavioural responses, nerve morphology and expression of pain marker, c-fos among CCI models developed with one, two, three and four ligations. The numbers of ligation(s) on sciatic nerve shows no significant difference in displaying mechanical and cold allodynia, and mechanical and thermal hyperalgesia throughout 84 days. All groups underwent similar levels of nerve degeneration post-surgery. Similar c-fos level in brain cingulate cortex, parafascicular nuclei and amygdala were observed in all CCI models compared to sham-operated group. Therefore, number of ligations does not impact intensity of pain symptoms, pathogenesis and neuronal activation. A single ligation is sufficient to develop neuropathic pain, in contrast to the established model of four ligations. This study dissects and characterises the CCI model, ascertaining a more uniform animal model to surrogate actual neuropathic pain condition.


Assuntos
Modelos Animais de Doenças , Camundongos Endogâmicos ICR , Neuralgia , Tonsila do Cerebelo/metabolismo , Tonsila do Cerebelo/patologia , Tonsila do Cerebelo/fisiopatologia , Animais , Constrição Patológica/complicações , Giro do Cíngulo/metabolismo , Giro do Cíngulo/patologia , Hiperalgesia/metabolismo , Hiperalgesia/fisiopatologia , Núcleos Intralaminares do Tálamo/metabolismo , Núcleos Intralaminares do Tálamo/patologia , Ligadura , Masculino , Neuralgia/etiologia , Neuralgia/metabolismo , Neuralgia/patologia , Neuralgia/fisiopatologia , Medição da Dor , Proteínas Proto-Oncogênicas c-fos/metabolismo , Nervo Isquiático/lesões , Nervo Isquiático/patologia , Neuropatia Ciática/etiologia , Neuropatia Ciática/metabolismo , Neuropatia Ciática/patologia , Neuropatia Ciática/fisiopatologia
6.
Life Sci ; 233: 116752, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31415770

RESUMO

AIMS: Few studies have compared the interaction of single and repeated administration of amitriptyline (amit) with the nitrergic system and glutamatergic system in the experimental model of neuropathic pain. We aimed to evaluate the antinociceptive effect of single and repeated administration of amit and to assess whether glutamate preceded inducible nitric oxide synthase (iNOS) inhibition as a mechanism of the analgesic effect of amit in the neuropathic model of pain. MATERIALS AND METHODS: Male Wistar rats were subjected to left sciatic nerve ligation. The effect of single (25 mg kg-1) and repeated (10 mg kg-1 daily for 3 weeks) administration of amit intraperitoneally (i.p.) alone or in combination with aminoguanidine (AG i.p., 100 mg kg-1 for 3 days, a selective iNOS inhibitor) and MK-801 (0.05 mg kg-1 i.p., NMDA antagonist) on resting paw posture and mechanical hyperalgesia were studied. Glutamate level and iNOS protein expression in hippocampus were detected. KEY FINDINGS: Single and repeated administration of amit alone or in combination with AG or MK-801 demonstrated a significant decrease in resting pain score and increase in the pain threshold. Both glutamate and nitrite levels decreased in the hippocampi of single and repeated amit + MK-801 groups. Immunohistochemistry showed a marked decrease in iNOS immunoreactivity in rats treated with single and repeated amit + MK-801. SIGNIFICANCE: Our results suggest that glutamate-dependent mechanisms are involved in the analgesic responses to amit administration. Importantly, glutamatergic system and its upstream nitrergic system play an important role in the antinociceptive action of amit.


Assuntos
Amitriptilina/farmacologia , Analgésicos não Entorpecentes/farmacologia , Ácido Glutâmico/metabolismo , Neuralgia/tratamento farmacológico , Nitrogênio/metabolismo , Amitriptilina/administração & dosagem , Analgésicos não Entorpecentes/administração & dosagem , Animais , Modelos Animais de Doenças , Masculino , Neuralgia/metabolismo , Neuralgia/patologia , Óxido Nítrico Sintase Tipo II/antagonistas & inibidores , Limiar da Dor , Ratos , Ratos Wistar
7.
Int J Mol Med ; 44(4): 1205-1218, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31432094

RESUMO

Neuropathic pain (NP) is a complex, chronic pain condition caused by injury or dysfunction affecting the somatosensory nervous system. This study aimed to identify crucial genes and miRNAs involved in NP. Microarray data (access number GSE91396) were downloaded from the Gene Expression Omnibus (GEO). Murine RNA­seq samples from three brain regions [nucleus accumbens, (NAc); medial prefrontal cortex, (mPFC) and periaqueductal gray, (PAG)]were compared between the spared nerve injury (SNI) model and a sham surgery. After data normalization, differentially expressed RNAs were screened using the limma package and functional enrichment analysis was performed with Database for Annotation, Visualization and Integrated Discovery. The microRNA (miRNA/miR)­mRNA regulatory network and miRNA­target gene­pathway regulatory network were constructed using Cytoscape software. A total of 2,776 differentially expressed RNAs (219 miRNAs and 2,557 mRNAs) were identified in the SNI model compared with the sham surgery group. A total of two important modules (red and turquoise module) were found to be related to NP using weighed gene co­expression network analysis (WGCNA) for the 2,325 common differentially expressed RNAs in three brain regions. The differentially expressed genes (DEGs) in the miRNA­mRNA regulatory network were significantly enriched in 21 Gene Ontology terms and five pathways. A total of four important DEGs (CXCR2, IL12B, TNFSF8 and GRK1) and five miRNAs (miR­208a­5p, miR­7688­3p, miR­344f­3p, miR­135b­3p and miR­135a­2­3p) were revealed according to the miRNA­target gene­pathway regulatory network to be related to NP. Four important DEGs (CXCR2, IL12B, TNFSF8 and GRK1) and five miRNAs (miR­208a­5p, miR­7688­3p, miR­344f­3p, miR­135b­3p and miR­135a­2­3p) were differentially expressed in SNI, indicating their plausible roles in NP pathogenesis.


Assuntos
Expressão Gênica , MicroRNAs/genética , Neuralgia/etiologia , Animais , Biologia Computacional/métodos , Bases de Dados Genéticas , Modelos Animais de Doenças , Progressão da Doença , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Ontologia Genética , Redes Reguladoras de Genes , Masculino , Camundongos , Neuralgia/tratamento farmacológico , Neuralgia/metabolismo , Neuralgia/fisiopatologia , RNA Mensageiro/genética , Transdução de Sinais
8.
Int J Mol Med ; 44(4): 1585-1593, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31364720

RESUMO

Neuropathic pain is one of most intense types of chronic pain. Numerous studies investigating neuropathic pain have described the critical involvement of microglia in the spinal cord. Previous studies have indicated that activation of large conductance Ca2+­activated K+ (BK) channels contributes to microglial activation in the spinal dorsal horn (SDH) and the generation of neuropathic pain. However, the specific role of BK channels in spinal microglia in neuropathic pain has not been fully addressed in previous studies, as BK channel inhibitors were used to inhibit microglial BK channel based on their inhibitory kinetics. We previously identified that Ca2+­activated K+ channel ß3 auxiliary subunit (KCNMB3), which is an auxiliary subunit of BK channels and regulates gating properties of the channel, is exclusively expressed in microglia in the spinal cord. The present study analyzed the role of BK channels in spinal microglia in neuropathic pain using a spinal microglia­specific BK channel knockdown method, with intrathecal injection of KCNMB3 small interfering RNA. Neuropathic pain was significantly attenuated in KCNMB3 knockdown mice. Increases in the number of microglia in the SDH following nerve injury were attenuated by KCNMB3 knockdown. Furthermore, increased levels of pain­associated molecules in the SDH were attenuated in KCNMB3 knockdown mice. Attempts were also made to analyze the effects of KCNMB3 knockdown on chronic pain. KCNMB3 knockdown ameliorated chronic pain and inhibited the expression levels of pain­associated molecules in the SDH. The results from the present study suggested that BK channels modulated the activation state of spinal microglia, and that KCNMB3 is a potential therapeutic target for neuropathic pain.


Assuntos
Subunidades beta do Canal de Potássio Ativado por Cálcio de Condutância Alta/genética , Microglia/metabolismo , Neuralgia/etiologia , Neuralgia/metabolismo , Medula Espinal/citologia , Medula Espinal/metabolismo , Animais , Modelos Animais de Doenças , Inativação Gênica , Subunidades beta do Canal de Potássio Ativado por Cálcio de Condutância Alta/metabolismo , Masculino , Camundongos , Camundongos Knockout
9.
World Neurosurg ; 132: e529-e534, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31449993

RESUMO

BACKGROUND: Spinal cord injury (SCI) is a common type of injury, and about half of patients affected by SCI will suffer from neuropathic pain within a year after injury. However, the treatment effect of neuropathic pain is far from satisfactory. Our study attempted to reveal whether salvianolic acid B (SalB) could relieve the neuropathic pain caused by SCI in mice by inhibiting the Toll-like receptor 4 (TLR4)/Myeloid differentiation factor 88 (MyD88) pathway. METHODS: The mice were randomly divided into a sham group, model group, high-dose treatment group, and low-dose treatment group. The high- and low-dose groups received varying doses of SalB after modeling. RESULTS: The increase of pain sensitivity was evaluated by detecting paw withdrawal mechanical threshold and withdrawal thermal latency. Messenger RNA and protein expression levels of TLR4 and myD88 were detected by using quantitative reverse-transcription polymerase chain reaction and western blot, respectively. Compared with the model group, there was a significant reduction in paw withdrawal mechanical threshold and withdrawal thermal latency after SalB treatment. CONCLUSIONS: SalB reduced the release of tumor necrosis factor-α and substance P by inhibiting the TLR4/MyD88 pathway in the SCI mouse model. This not only resulted in lower pain, but also contributed to long-term relief of mechanical hyperalgesia.


Assuntos
Benzofuranos/farmacologia , Fator 88 de Diferenciação Mieloide/efeitos dos fármacos , Neuralgia/metabolismo , Limiar da Dor/efeitos dos fármacos , Traumatismos da Medula Espinal/metabolismo , Receptor 4 Toll-Like/efeitos dos fármacos , Animais , Hiperalgesia/etiologia , Hiperalgesia/imunologia , Hiperalgesia/metabolismo , Masculino , Camundongos , Neuralgia/etiologia , Neuralgia/imunologia , Distribuição Aleatória , Traumatismos da Medula Espinal/complicações , Traumatismos da Medula Espinal/imunologia
10.
Int J Mol Sci ; 20(17)2019 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-31454988

RESUMO

Diverse transcriptional controls in the dorsal horn have been observed in pain hypersensitivity. However, the understanding of the exact causes and mechanisms of neuropathic pain development is still fragmentary. Here, the results demonstrated nerve injury decreased the expression of spinal hairy and enhancer of split 1 (Hes1), a transcriptional repressor, and enhanced metabotropic glutamate receptor subtype 5 (mGluR5) transcription/expression, which was accompanied with behavioral allodynia. Moreover, nerve injury decreased Hes1 levels and reciprocally increased cyclin dependent kinase-9 (CDK9) levels and recruited CDK9 to phosphorylate RNA polymerase II (RNAPII) in the promoter fragments of mGluR5, thereby enhancing mGluR5 transcription/expression in the dorsal horn. These effects were also induced by intrathecally administering naïve rats with Hes1 small interfering RNA (siRNA). Conversely, Hes1 overexpression using intrathecal lentiviral vectors in nerve injury rats produced reversal of pain behavior and reversed protein expressions, phosphorylation, and coupling to the promoter segments in the dorsal horn. Collectively, the results in this study indicated nerve injury diminishes spinal Hes1-dependent suppression of CDK9-dependent RNAPII phosphorylation on the mGluR5 promoter that possibly enhances mGluR5 transcription/expression for neuropathic pain development.


Assuntos
Quinase 9 Dependente de Ciclina/metabolismo , Neuralgia/etiologia , Neuralgia/metabolismo , RNA Polimerase II/metabolismo , Receptor de Glutamato Metabotrópico 5/genética , Medula Espinal/metabolismo , Fatores de Transcrição HES-1/genética , Animais , Comportamento Animal , Modelos Animais de Doenças , Expressão Gênica , Regulação da Expressão Gênica , Técnicas de Silenciamento de Genes , Hiperalgesia/etiologia , Hiperalgesia/metabolismo , Masculino , Fenótipo , Regiões Promotoras Genéticas , Ligação Proteica , Ratos , Medula Espinal/fisiopatologia , Fatores de Transcrição HES-1/metabolismo , Fatores de Transcrição/metabolismo , Transcrição Genética
11.
J Physiol Sci ; 69(5): 769-777, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31267368

RESUMO

Operant methods that allow animals to avoid painful stimuli are interpreted to assess the aversive quality of pain; however, such measurements require investigator-initiated stimuli to animals. Here we developed a shuttle maze test to repeatedly assess activity associated nociception without forced stimulation. Rats ambulate back and forth between two treat feeders by taking either a short route with a prickly surfaced arch or a longer route with a smooth floor. L5-L6 spinal nerve ligation (SNL) reduced the preference for the short route with the arch, correlated with hypersensitivity in the hind paw. Oral gabapentin restored the short route preference and reduced hypersensitivity in SNL rats, and blockade of spinal α2-adrenoceptors reduced gabapentin's effects on hypersensitivity but not on preference index. These results suggest that SNL injury alters behavior in the shuttle maze test and that the shuttle maze test shows comparable results to reflexive hypersensitivity after SNL in magnitude and response to gabapentin.


Assuntos
Comportamento de Escolha/fisiologia , Traumatismos dos Nervos Periféricos/fisiopatologia , Animais , Modelos Animais de Doenças , Alimentos , Hiperalgesia/metabolismo , Hiperalgesia/fisiopatologia , Ligadura/métodos , Masculino , Neuralgia/metabolismo , Neuralgia/fisiopatologia , Limiar da Dor/fisiologia , Ratos , Ratos Sprague-Dawley , Nervos Espinhais/metabolismo , Nervos Espinhais/fisiopatologia , Ácido gama-Aminobutírico/metabolismo
12.
Pain Res Manag ; 2019: 2612534, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31281556

RESUMO

Objective: To explore the role of purine family member P2Y6 receptors in regulating neuropathic pain (NP) via neuroinflammation in the spinal cord. Methods: Chronic constriction injury of the sciatic nerve (CCI) of NP was classic in setting up models on Sprague-Dawley (SD) rats. Experiments were performed on rats with sham surgery, CCI, CCI + MRS2578 (a P2Y6 receptor antagonist), and UDP (a P2Y6 receptor agonist). The hyperalgesia intensity was mirrored by paw withdrawal threshold (PWT) and thermal withdrawal latency (TWL). Immunofluorescence staining and western blot were used to evaluate activated microglial marker Iba-1. Enzyme-linked immunosorbent assay (ELISA) was used to access levels of IL-6. Conventional reverse transcription polymerase chain reaction (RT-PCR) and western blot analysis were used to detect the expression of P2Y6 mRNA and activation of JAK/STAT signaling. Results: Among all groups, CCI caused decreased PWT and TWL compared to sham surgery, meaning a successful establishment of the NP model. These decreased values of PWT and TWL tests could be prevented by intraperitoneally injected MRS2578 and enhanced by UDP administration. Similarly, CCI induced increase of Iba-1 protein, P2Y6 mRNA expression, and circulating IL-6 secretion, as well as increased JAK2/STAT3 mRNA expression and phosphorylating modification in spinal cord tissues could also be diminished by MRS2578 treatment and exacerbated by UDP. Conclusions: These findings indicated the crucial role of the P2Y6 receptor in modulating the microglial and inflammatory responses in the process of NP in vivo. Results from this study would provide insights into targeting the P2Y6 receptor to treat NP in the near future.


Assuntos
Neuralgia/metabolismo , Receptores Purinérgicos P2/metabolismo , Animais , Hiperalgesia/metabolismo , Isotiocianatos/farmacologia , Masculino , Ratos , Ratos Sprague-Dawley , Nervo Isquiático/lesões , Tioureia/análogos & derivados , Tioureia/farmacologia , Difosfato de Uridina/farmacologia
13.
Neurochem Res ; 44(9): 2068-2080, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31317507

RESUMO

The mechanisms underlying chronic and neuropathic pain pathology involve peripheral and central sensitisation. The medial prefrontal cortex (mPFC) seems to participate in pain chronification, and glutamatergic neurotransmission may be involved in this process. Thus, the aim of the present work was to investigate the participation of the prelimbic (PrL) area of the mPFC in neuropathic pain as well as the role of N-methyl D-aspartate (NMDA) glutamate receptors in neuropathic pain induced by a modified sciatic nerve chronic constriction injury (CCI) protocol in Wistar rats. Neural inputs to the PrL cortex were inactivated by intracortical treatment with the synapse blocker cobalt chloride (CoCl2, 1.0 mM/200 nL) 7, 14, 21, or 28 days after the CCI or sham procedure. The glutamatergic agonist NMDA (0.25, 1 or 4 nmol) or the selective NMDA receptor antagonist LY235959 (2, 4 or 8 nmol) was microinjected into the PrL cortex 21 days after surgery. CoCl2 administration in the PrL cortex decreased allodynia 21 and 28 days after CCI. NMDA at 1 and 4 nmol increased allodynia, whereas LY235959 decreased mechanical allodynia at the highest dose (8 nmol) microinjected into the PrL cortex. These findings suggest that NMDA receptors in the PrL cortex participate in enhancing the late phase of mechanical allodynia after NMDA-induced increases and LY235959-induced decreases in allodynia 21 days after CCI. The glutamatergic system potentiates chronic neuropathic pain by NMDA receptor activation in the PrL cortex. Mechanism of neuropathic pain. The infusion of CoCl2, a synapse activity blocker, into the prelimbic (PrL) division of the medial prefrontal cortex (mPFC) decreased the severity of mechanical allodynia, showing the late participation of the limbic cortex. The glutamatergic system potentiates chronic neuropathic pain via NMDA receptor activation in the PrL cortex.


Assuntos
Neuralgia/metabolismo , Nervos Periféricos/metabolismo , Córtex Pré-Frontal/metabolismo , Receptores de N-Metil-D-Aspartato/metabolismo , Animais , Cobalto/farmacologia , Hiperalgesia/tratamento farmacológico , Isoquinolinas/farmacologia , Masculino , N-Metilaspartato/farmacologia , Neuralgia/tratamento farmacológico , Traumatismos dos Nervos Periféricos/tratamento farmacológico , Córtex Pré-Frontal/efeitos dos fármacos , Ratos Wistar , Transmissão Sináptica/efeitos dos fármacos
14.
Chin Med J (Engl) ; 132(14): 1706-1712, 2019 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-31261200

RESUMO

BACKGROUND: Pulsed radiofrequency (PRF) is a minimally invasive interventional technique that provides a novel and effective treatment strategy for neuropathic pain (NP). PRF is advantageous because it does not damage nerves and avoids sensory loss after treatment. At present, animal studies have demonstrated that PRF is safe and effective for relieving the NP associated with sciatic nerve damage in rats with chronic constriction injury (CCI). However, the mechanism through which this effect occurs is unknown. An increasing body of evidence shows that the expression of the P2X ligand-gated ion channel 3 (P2X3) receptor is closely related to NP; this study was to investigate whether the expression of this receptor is involved in NP relief due to PRF. METHODS: A total of 36 healthy adult male Sprague-Dawley (SD) rats were randomly divided into three groups: Sham group, CCI group, and PRF group. The right sciatic nerve was ligated in CCI group and PRF group to establish a CCI model; the right sciatic nerve was separated but not ligated in Sham group. On day 14 after the operation, PRF was administered to the ligated sciatic nerve in PRF group (42°C, 45 V, 2 min). A non-live electrode was placed at the exposed sciatic nerve for the rats in Sham and CCI groups. The hindpaw withdrawal threshold (HWT) and thermal withdrawal latency (TWL) were measured at the right hindpaw at different time points before and after PRF or sham therapy. On day 28 after treatment, the dorsal root ganglion (DRG) and spinal dorsal horn of the right L4-6 were harvested from each group to determine the mRNA and protein levels of the P2X3 receptor. RESULTS: On day 28 after PRF treatment, the HWT (8.33 ±â€Š0.67 g vs. 3.62 ±â€Š0.48 g) and TWL (25.42 ±â€Š1.90 s vs. 15.10 ±â€Š1.71 s) were significantly higher in PRF group as compared to CCI group (P < 0.05). The mRNA expression of the P2X3 receptor in the DRG in PRF group was 23.7% lower than that in CCI group (P < 0.05), in the spinal dorsal horns in PRF group was 22.7% lower than that in CCI group (P < 0.05). The protein expression of the P2X3 receptor in the DRG in PRF group was 27.8% lower than that in CCI group (P < 0.05), in the spinal dorsal horns in PRF group was 35.6% lower than that in CCI group (P < 0.05). CONCLUSION: PRF possibly reduces NP in CCI rats by inhibiting the expression of the P2X3 receptor in the L4-6 DRG and spinal dorsal horns.


Assuntos
Constrição , Neuralgia/metabolismo , Neuralgia/terapia , Traumatismos dos Nervos Periféricos/metabolismo , Traumatismos dos Nervos Periféricos/terapia , Tratamento por Radiofrequência Pulsada/métodos , Receptores Purinérgicos P2X3/metabolismo , Animais , Masculino , Ratos , Ratos Sprague-Dawley , Neuropatia Ciática/metabolismo , Neuropatia Ciática/terapia
15.
BMC Res Notes ; 12(1): 413, 2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-31307541

RESUMO

OBJECTIVE: 5-HOB is a novel tissue selective, 5-hydroxybenzothiazolone-derived ß2 adrenoceptor agonist with minimized cardiovascular effects while retaining efficacy on skeletal muscle in preclinical experiments unlike conventional ß2 adrenoceptor agonists, however its effect on the nervous system has not been evaluated yet. Therefore, 5-HOB was evaluated in a mouse model of neuropathic pain. RESULTS: 5-HOB alleviated neuropathic allodynia in a dose dependent manner and reversed the changes in hind paw withdrawal thresholds to the sham control levels. The dose attenuating neuropathic allodynia was slightly lower than the dose inducing skeletal muscle hypertrophy. In conclusion, as reported with known ß2 adrenoceptor agonists, 5-HOB was also effective in attenuating neuropathic pain in mice in addition to its effect on skeletal muscle.


Assuntos
Agonistas de Receptores Adrenérgicos beta 2/farmacologia , Hiperalgesia/prevenção & controle , Neuralgia/prevenção & controle , Receptores Adrenérgicos beta 2/metabolismo , Agonistas de Receptores Adrenérgicos beta 2/química , Animais , Benzotiazóis/química , Benzotiazóis/farmacologia , Modelos Animais de Doenças , Humanos , Hiperalgesia/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Neuralgia/metabolismo , Medição da Dor/métodos
16.
Neurosci Lett ; 708: 134365, 2019 08 24.
Artigo em Inglês | MEDLINE | ID: mdl-31278961

RESUMO

INTRODUCTION: Recent evidence shows that numerous microRNAs (miRNAs) regulate pain-related genes in chronic pain. The aim of the present study was to further explore the regulation of miRNAs and their effect on the expression of pain-associated target genes in experimental neuropathic pain. METHODS: Male Wistar rats underwent chronic constriction injury (CCI) of the sciatic nerve or Sham procedure. After assessment of mechanical allodynia, the ipsilateral dorsal root ganglia (DRG) were harvested. MiRNA expression levels were analysed with Agilent microRNA microarrays and real time quantitative PCR. An interaction between miRNAs and pain-relevant genes was confirmed by luciferase assays. Western Blot analysis and ELISA were performed to evaluate protein expression, respectively. RESULTS: Mechanical allodynia developed within 6 days after CCI. MiRNA-arrays revealed the differential expression of 49 miRNAs after 4 h, of 3 miRNAs after 1 d, of 26 miRNAs after 6 d and of 28 miRNAs after 12 d in the CCI group versus Sham. Time-dependent down regulation of miR-34a was verified by qPCR. Bioinformatic prediction revealed an interaction with several pain-relevant targets including voltage-gated sodium channel ß2 subunit (SCN2B) and vesicle-associated membrane protein 2 (VAMP-2), both of which were subsequently confirmed by luciferase assay. VAMP-2 expression was statistically significantly increased 12 d after CCI. A non-significant upregulation of SCN2B in the DRG after CCI was confirmed by ELISA. DISCUSSION: Peripheral mononeuropathic pain in rats was associated with distinct alterations of miRNA expression in the ipsilateral DRG. Notably, miR-34a was time-dependently down regulated. We validated SCN2B and VAMP-2 as new targets of miR-34a. While SCN2B expression was only marginally altered, VAMP-2 expression was increased. The present study underlines that the induction and maintenance of neuropathic pain is accompanied by expression changes of miRNAs in the peripheral nervous system, adding several previously unreported miRNAs, including miR-34a.


Assuntos
Gânglios Espinais/metabolismo , MicroRNAs/metabolismo , Neuralgia/metabolismo , Nervo Isquiático/lesões , Animais , Doença Crônica , Constrição , Hiperalgesia/fisiopatologia , Masculino , Neuralgia/fisiopatologia , Ratos Wistar , Fatores de Tempo , Proteína 2 Associada à Membrana da Vesícula/genética , Proteína 2 Associada à Membrana da Vesícula/metabolismo , Subunidade beta-2 do Canal de Sódio Disparado por Voltagem/genética , Subunidade beta-2 do Canal de Sódio Disparado por Voltagem/metabolismo
17.
Int J Immunopathol Pharmacol ; 33: 2058738419866379, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31337260

RESUMO

We aimed to analyze the action of berberine on the neuropathic pain and neuroglia activation in experimental diabetes mellitus (DM) model. Diabetes in mice was induced by intraperitoneal injection of streptozotocin (STZ) followed by the administration of berberine. Mechanical allodynia and thermal hyperalgesia and activations of microglia and astrocytes were evaluated. The levels of pro-inflammatory cytokines and protein expressions of inflammatory proteins were assessed by enzyme-linked immunosorbent assay (ELISA) and western blot, respectively. Our results revealed the anti-nociceptive effects of berberine in DM mice, supported by the improved mechanical threshold and thermal latency. In addition, berberine suppressed the activations of microglia and astrocytes in the spinal cords of diabetic mice. Berberine inhibited the expression of pro-inflammatory cytokines including tumor necrosis factor (TNF)-α, interleukin-6 (IL-6), and interleukin-1ß (IL-1ß), along with inflammatory proteins including iNOS and COX-2. Berberine suppressed neuropathic pain in STZ-induced diabetic mice, and this effect is related to the reduction on the neuroglia activation and inflammation associated with DM.


Assuntos
Berberina/farmacologia , Diabetes Mellitus Experimental/induzido quimicamente , Diabetes Mellitus Experimental/tratamento farmacológico , Hiperalgesia/tratamento farmacológico , Inflamação/tratamento farmacológico , Estreptozocina/farmacologia , Animais , Astrócitos/efeitos dos fármacos , Astrócitos/metabolismo , Citocinas/metabolismo , Diabetes Mellitus Experimental/metabolismo , Hiperalgesia/metabolismo , Inflamação/metabolismo , Interleucina-1beta/metabolismo , Interleucina-6/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Microglia/efeitos dos fármacos , Microglia/metabolismo , Neuralgia/tratamento farmacológico , Neuralgia/metabolismo , Óxido Nítrico Sintase Tipo II/metabolismo , Medula Espinal/efeitos dos fármacos , Medula Espinal/metabolismo , Fator de Necrose Tumoral alfa/metabolismo
18.
Biomed Res Int ; 2019: 8941046, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31240228

RESUMO

Chloride (Cl-) homeostasis is an essential process involved in neuronal signalling and cell survival. Inadequate regulation of intracellular Cl- interferes with synaptic signalling and is implicated in several neurological diseases. The main inhibitory neurotransmitter of the central nervous system is γ-aminobutyric acid (GABA). GABA hyperpolarises the membrane potential by activating Cl- permeable GABAA receptor channels (GABAAR). This process is reliant on Cl- extruder K+-Cl- cotransporter 2 (KCC2), which generates the neuron's inward, hyperpolarising Cl- gradient. KCC2 is encoded by the fifth member of the solute carrier 12 family (SLC12A5) and has remained a poorly understood component in the development and severity of many neurological diseases for many years. Recent advancements in next-generation sequencing and specific gene targeting, however, have indicated that loss of KCC2 activity is involved in a number of diseases including epilepsy and schizophrenia. It has also been implicated in neuropathic pain following spinal cord injury. Any variant of SLC12A5 that negatively regulates the transporter's expression may, therefore, be implicated in neurological disease. A recent whole exome study has discovered several causative mutations in patients with epilepsy. Here, we discuss the implications of KCC2 in neurological disease and consider the evolving evidence for KCC2's potential as a therapeutic target.


Assuntos
Canais de Cloreto/metabolismo , Neurônios/metabolismo , Simportadores/antagonistas & inibidores , Simportadores/metabolismo , Ácido gama-Aminobutírico/farmacologia , Sistema Nervoso Central/efeitos dos fármacos , Sistema Nervoso Central/metabolismo , Cloretos/metabolismo , Epilepsia/metabolismo , Marcação de Genes , Homeostase , Humanos , Potenciais da Membrana , Neuralgia/metabolismo , Neurotransmissores/farmacologia , Fosforilação , Esquizofrenia/metabolismo , Membro 2 da Família 12 de Carreador de Soluto/metabolismo , Traumatismos da Medula Espinal , Simportadores/genética
19.
Pain Res Manag ; 2019: 5948686, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31182984

RESUMO

Background: Pulsed radiofrequency (PRF) on the dorsal root ganglion (DRG) has been applied to alleviate neuropathic pain effectively, yet the mechanisms underlying pain reduction owing to this treatment are not clarified completely. The activated microglia, brain-derived neurotrophic factor (BDNF), phosphatidylinositol 3-kinase (PI3K), and phosphorylated extracellular signal-regulated kinase (p-ERK) in the spinal cord were demonstrated to be involved in developing neuropathic pain. Also, it has been just known that PRF on DRG inhibits the microglial activation in nerve injury rats. Here, we aim to investigate whether PRF treatment could regulate the levels of BDNF, PI3K, and p-ERK in the spinal cord of rats with spared nerve injury (SNI) via suppressing the spinal microglia activation to ease neuropathic pain. Methods: The rats with SNI were intrathecally treated with minocycline (specific microglia inhibitor) or same volume of dimethyl sulfoxide once daily, beginning from 1 h before nerve transection to 7 days. PRF was applied adjacent to the L4-L5 DRG of rats with SNI at 45 V for 6 min on the seventh postoperative day, whereas the free-PRF rats were treated without PRF. The withdrawal thresholds were studied, and the spinal levels of ionized calcium-binding adapter molecule 1 (Iba1), BDNF, PI3K, and p-ERK were calculated by western blot analysis, reverse transcription-polymerase chain reaction, and immunofluorescence. Results: The paw withdrawal mechanical threshold and paw withdrawal thermal latency decreased in the ipsilateral hind paws after SNI, and the spinal levels of Iba1, BDNF, PI3K, and p-ERK increased on day 21 after SNI compared with baseline (P < 0.01). An intrathecal injection of minocycline led to the reversal of SNI-induced allodynia and increase in levels of Iba1, BDNF, PI3K, and p-ERK. Withdrawal thresholds recovered partially after a single PRF treatment for 14 days, and SNI-induced microglia hyperactivity, BDNF upregulation, and PI3K and ERK phosphorylation in the spinal cord reduced on D14 due to the PRF procedure. Conclusion: Microglial BDNF, PI3K, and p-ERK in the spinal cord are suppressed by the therapy of PRF on DRG to ease SNI-induced neuropathic pain in rats.


Assuntos
Microglia/metabolismo , Neuralgia/metabolismo , Tratamento por Radiofrequência Pulsada , Medula Espinal/metabolismo , Animais , Fator Neurotrófico Derivado do Encéfalo/biossíntese , Modelos Animais de Doenças , MAP Quinases Reguladas por Sinal Extracelular/biossíntese , Gânglios Espinais/metabolismo , Masculino , Neuralgia/etiologia , Traumatismos dos Nervos Periféricos/complicações , Fosfatidilinositol 3-Quinase/biossíntese , Tratamento por Radiofrequência Pulsada/métodos , Ratos , Ratos Sprague-Dawley
20.
Anal Cell Pathol (Amst) ; 2019: 8253850, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31223559

RESUMO

Background: Neuropathic pain not only affects individual life quality but also increases economic burden for the society. Treatment to alleviate neuropathic pain is required. Methodology: Fifty rats were randomly assigned into sham, spinal nerve ligation, and three treatment groups with different doses of Tempol (100, 200, and 300 mg/kg, respectively), with 10 rats in each group. A neuropathic pain model was created with spinal nerve L5 and L6 ligation. Mechanical allodynia and thermal hyperalgesia were tested preoperatively (day 0) and postoperatively (days 1, 3, 5, and 7). Spinal cord levels of nitric oxide, as well as activities of nitric oxide synthase and acetylcholinesterase, were tested in postoperative day 7. Results: Compared with rats in the spinal nerve ligation group, rats in Tempol treatment groups had decreased responses to mechanical pain and cold plate stimulations. A high dose of Tempol produced more attenuating effects. The level of nitric oxide and activity of nitric oxide synthase were also decreased with Tempol treatments, whereas no significant changes were observed in the activity of acetylcholinesterase. Conclusions: Tempol attenuated an experimental rat model with neuropathic pain by inhibiting nitric oxide production.


Assuntos
Óxidos N-Cíclicos/farmacologia , Neuralgia/tratamento farmacológico , Neuralgia/metabolismo , Fármacos Neuroprotetores/farmacologia , Óxido Nítrico/antagonistas & inibidores , Animais , Óxidos N-Cíclicos/uso terapêutico , Masculino , Fármacos Neuroprotetores/uso terapêutico , Óxido Nítrico/metabolismo , Ratos , Ratos Sprague-Dawley , Marcadores de Spin , Nervos Espinhais/fisiopatologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA