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1.
Invest Ophthalmol Vis Sci ; 61(1): 4, 2020 01 23.
Artigo em Inglês | MEDLINE | ID: mdl-31999819

RESUMO

Purpose: Neurotrophic keratopathy is a degenerative disease that may be improved by nerve growth factor (NGF). Our aim was to investigate the use of pergolide, a dopamine (D1 and D2) receptor agonist known to increase the synthesis and release of NGF for regeneration of damaged corneal nerve fibers. Methods: Pergolide function was evaluated by measuring axon length and NGF levels by enzyme-linked immunosorbent assay in cultured chicken dorsal root ganglion (DRG) cells with serial doses of pergolide (10, 25, 50, 150, and 300 µg/ml) and with different concentrations of a D1 antagonist. Pergolide function was further evaluated by cornea nerve fiber density and wound healing in a cornea scratch mouse model. Results: Pergolide increased DRG axon length significantly at a dose between 50 and 300 µg/ml. Different concentrations of D1 antagonist (12, 24, 48, and 96 µg/ml) inhibited DRG axon length growth with pergolide (300 µg/ml). Pergolide (50 µg/ml) upregulated NGF expression in DRG cells at both 24 hours and 48 hours. Pergolide improved cornea nerve fiber density at both 1 week and 2 weeks. Pergolide also improved cornea wound healing. Conclusions: We demonstrated that pergolide can act to promote an increase in NGF which promotes corneal nerve regeneration and would therefore improve corneal sensation and visual acuity in eyes with peripheral neurotrophic keratopathy.


Assuntos
Lesões da Córnea/tratamento farmacológico , Agonistas de Dopamina/uso terapêutico , Fibras Nervosas/efeitos dos fármacos , Pergolida/uso terapêutico , Animais , Axônios/efeitos dos fármacos , Galinhas , Agonistas de Dopamina/farmacologia , Gânglios Espinais/efeitos dos fármacos , Camundongos , Regeneração Nervosa , Pergolida/farmacologia , Cicatrização/fisiologia
2.
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
3.
Chem Biol Interact ; 315: 108890, 2020 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-31678597

RESUMO

The monoterpenoid terpinen-4-ol (4TERP) is known to inhibit cell excitability, has low toxicity and important pharmacological activities, which are likely related to neural excitability, such as anti-inflammatory, antiepileptic and antinociceptive effects. However, the pharmacological characteristics and mechanisms underlying the effects of 4TERP on blockade of neural action potential are not completely elucidated. Since Na+ current (INa) through voltage-dependent Na+ channels (NaV) is a major mechanism for excitability, the present study investigated the pharmacological characteristics and mechanisms of the action of 4TERP on INa through NaV. For this aim, dissociated small neurons of dorsal root ganglia of adult rats were used for whole cell patch-clamp recordings. 4TERP concentration-dependently inhibits INa (IC50 0.8 ±â€¯0.3 mM; pharmacological efficacy 42.89 ±â€¯5.54%). 4TERP interfered with INa through a mechanism with various components, which includes predominantly channel pore block and sensitivity to frequency of use. In presence of 4TERP (3 mM), decreasing stimulation from 5 Hz to very low frequency (75 s of quiescence previously to stimulation) induced INa decrease to 65.17 ±â€¯5.86% of control. 4TERP also altered (left shift) voltage sensitivity of the steady state activation of NaV. Data are discussed aiming to interpret the importance of blockade of INa through NaV as participant of 4TERP-induced inhibition of membrane excitability.


Assuntos
Gânglios Espinais/efeitos dos fármacos , Monoterpenos/farmacologia , Neurônios/efeitos dos fármacos , Terpenos/farmacologia , Bloqueadores do Canal de Sódio Disparado por Voltagem/farmacologia , Canais de Sódio Disparados por Voltagem/metabolismo , Potenciais de Ação/efeitos dos fármacos , Animais , Feminino , Gânglios Espinais/metabolismo , Masculino , Neurônios/metabolismo , Técnicas de Patch-Clamp/métodos , Ratos , Ratos Wistar
4.
Toxicol Lett ; 318: 104-113, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31672611

RESUMO

BACKGROUND: Bupivacaine (BP) is commonly used as a local anaesthetic(LA) in the clinic, but it can also cause neurotoxicity, especially in patients with diabetes. Previous studies have found that high-glucose environments can aggravate BP-induced DNA damage in nerve cells. Ku70 is subunit of the DNA damage repair enzyme DNA-PK. This study was designed to determine whether high-glucose conditions enhance BP neurotoxicity and DNA damage by inhibiting Ku70 expression. METHODS: We examined the effect of BP on apoptosis and DNA damage in murine dorsal root ganglion (DRG) neurons under hyperglycaemic conditions. Untreated DRG cells and DRG cells pretreated with NU7441, a DNA-PK inhibitor, were cultured for 3 days under normal culture conditions or with 50 mM glucose, and the cells were then treated with BP for 3 h. DNA damage was investigated via comet assays, the ratio of early to late apoptotic cells was assessed by Annexin V-FITC/PI staining, and cell viability was measured by CCK-8 assays. The protein expression levels of DNA-PK, Ku70, Bax, Bcl-2 and γH2ax were measured by immunofluorescence or Western blotting. RESULTS: Compared to its effect under normal culture conditions, BP treatment led to decreased cell viability and increased DNA damage in DRG cells grown under high-glucose conditions. The rate of DRG cell apoptosis and the expression of γH2ax, the ratio of Bax to Bcl-2 also increased under the high-glucose conditions. Furthermore, Ku70 expression was inhibited. The DNA-PK inhibitor, NU7441, could significantly inhibit DNA-PK and Ku70 expression, simultaneously further aggravating BP-induced apoptosis and DNA damage under high-glucose conditions. CONCLUSION: These data indicate that hyperglycaemia may enhance BP-induced neurotoxicity and DNA damage by inhibiting the DNA repair protein Ku70.


Assuntos
Anestésicos Locais/toxicidade , Apoptose/efeitos dos fármacos , Bupivacaína/toxicidade , Cromonas/toxicidade , Inibidores Enzimáticos/toxicidade , Gânglios Espinais/efeitos dos fármacos , Glucose/toxicidade , Autoantígeno Ku/antagonistas & inibidores , Morfolinas/toxicidade , Síndromes Neurotóxicas/etiologia , Animais , Células Cultivadas , Dano ao DNA , Gânglios Espinais/enzimologia , Gânglios Espinais/patologia , Autoantígeno Ku/metabolismo , Camundongos , Síndromes Neurotóxicas/enzimologia , Síndromes Neurotóxicas/patologia , Transdução de Sinais/efeitos dos fármacos
5.
Life Sci ; 239: 116961, 2019 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-31654745

RESUMO

Neuropathic pain (NP) is a difficult condition to treat because of the modest efficacy of available drugs. New treatments are required. In the study we aimed to investigate the effects of the essential oil from Lippia grata alone or complexed in ß-cyclodextrin (LG or LG-ßCD) on persistent inflammatory and neuropathic pain in a mouse model. We also investigated Ca2+ currents in rat dorsal root ganglion (DRG) neurons. Male Swiss mice were treated with LG or LG/ß-CD (24 mg/kg, i.g.) and their effect was evaluated using an acute inflammatory pleurisy model and nociception triggered by intraplantar injection of an agonist of the TRPs channels. We also tested their effect in chronic pain models: injection of Freund's Complete Adjuvant and partial sciatic nerve ligation (PSNL). In the pleurisy model, LG reduced the number of leukocytes and the levels of TNF-α and IL-1ß. It also inhibited cinnamaldehyde and menthol-induced nociceptive behavior. The pain threshold in mechanical and thermal hyperalgesia was increased and paw edema was decreased in models of inflammatory and neuropathic pain. PSNL increased inflammatory protein contents and LG and LG-ßCD restored the protein contents of TNF-α, NF-κB, and PKA, but not IL-1ß and IL-10. LG inhibited voltage gated Ca2+ channels from DRG neurons. Our results suggested that LG or LG-ßCD produce anti-hyperalgesic effect in chronic pain models through reductions in TNF-α levels and PKA, and inhibited voltage-gated calcium channels and may be innovative therapeutic agents for the management of NP.


Assuntos
Hiperalgesia/tratamento farmacológico , Lippia/metabolismo , beta-Ciclodextrinas/farmacologia , Animais , Dor Crônica/tratamento farmacológico , Modelos Animais de Doenças , Gânglios Espinais/efeitos dos fármacos , Hiperalgesia/metabolismo , Masculino , Camundongos , Neuralgia/tratamento farmacológico , Nociceptividade/efeitos dos fármacos , Óleos Voláteis/farmacologia , Dor/tratamento farmacológico , Dor/metabolismo , Medição da Dor/efeitos dos fármacos , Limiar da Dor/efeitos dos fármacos , Extratos Vegetais/farmacologia , Ratos , Ratos Wistar , beta-Ciclodextrinas/metabolismo
6.
Nan Fang Yi Ke Da Xue Xue Bao ; 39(9): 1078-1082, 2019 Sep 30.
Artigo em Chinês | MEDLINE | ID: mdl-31640967

RESUMO

OBJECTIVE: To observe the effect of cinobufagin on transient outward potassium current (IA) in rat dorsal root ganglion cells of cancer-induced bone pain (CIBP) and explore the possible analgesic mechanism of cinobufagin. METHODS: Whole cell patch clamp technique was used to examine the effect of cionbufagin on IA in acutely isolated dorsal root ganglion (DRG) cells from normal SD rats and rats with bone cancer pain. RESULTS: The DRG cells from rats with CIBP showed obviously decreased IA current density, an activation curve shift to the right, and an inactivation curve shift to the left. Cinobufagin treatment significantly increased the IA current density and reversed the changes in the activation and inactivation curves in the DRG cells. CONCLUSIONS: IA current is decreased in DRG neurons from rats with CIBP. Cinobufagin can regulate the activation and inactivation of IA current in the DRG cells, which may be related to its analgesic mechanism.


Assuntos
Analgésicos/farmacologia , Bufanolídeos/farmacologia , Dor do Câncer/tratamento farmacológico , Gânglios Espinais/efeitos dos fármacos , Canais de Potássio/metabolismo , Animais , Células Cultivadas , Técnicas de Patch-Clamp , Ratos , Ratos Sprague-Dawley
7.
Nat Commun ; 10(1): 4830, 2019 10 23.
Artigo em Inglês | MEDLINE | ID: mdl-31645570

RESUMO

Central nervous system (CNS) injuries persist for years, and currently there are no therapeutics that can address the complex injury cascade that develops over this time-scale. 17ß-estradiol (E2) has broad tropism within the CNS, targeting and inducing beneficial phenotypic changes in myriad cells following injury. To address the unmet need for vastly prolonged E2 release, we report first-generation poly(pro-E2) biomaterial scaffolds that release E2 at nanomolar concentrations over the course of 1-10 years via slow hydrolysis in vitro. As a result of their finely tuned properties, these scaffolds demonstrate the ability to promote and guide neurite extension ex vivo and protect neurons from oxidative stress in vitro. The design and testing of these materials reported herein demonstrate the first step towards next-generation implantable biomaterials with prolonged release and excellent regenerative potential.


Assuntos
Astrócitos/efeitos dos fármacos , Materiais Biocompatíveis , Estradiol/farmacologia , Estrogênios/farmacologia , Gânglios Espinais/efeitos dos fármacos , Crescimento Neuronal/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Animais , Animais Recém-Nascidos , Fármacos do Sistema Nervoso Central/administração & dosagem , Fármacos do Sistema Nervoso Central/química , Fármacos do Sistema Nervoso Central/farmacologia , Implantes de Medicamento/química , Estradiol/administração & dosagem , Estradiol/química , Estrogênios/administração & dosagem , Estrogênios/química , Técnicas In Vitro , Macrófagos , Fármacos Neuroprotetores/administração & dosagem , Fármacos Neuroprotetores/química , Fármacos Neuroprotetores/farmacologia , Polímeros/química , Cultura Primária de Células , Pró-Fármacos/administração & dosagem , Pró-Fármacos/química , Pró-Fármacos/farmacologia , Ratos , Medula Espinal/citologia
8.
Mater Sci Eng C Mater Biol Appl ; 104: 109902, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31500033

RESUMO

OBJECTIVE: This study sought to promote the adhesion, proliferation and differentiation of rat bone marrow mesenchymal stem cells by constructing a neurotrophin-3 (NT-3) sustained-release system cross-linked with an acellular spinal cord scaffold. METHODS: 1-Ethyl-3-[3-dimethylaminopropyl] carbodiimide hydrochloride (EDC) chemistry combined with chemical extraction was used to construct an acellular spinal cord scaffold. The decellularization completion was validated. An EDC cross-linking method was used to construct the NT-3 cross-linked acellular spinal scaffold. ELISA was used to verify sustained release of NT-3; the dorsal root ganglion method was used to verify the biological activity of the sustained-release NT-3. DAPI staining was used to confirm the adhesion of the cultured rat bone marrow mesenchymal stem cells (P3) to the NT-3 scaffold, and cell counting kit-8 (CCK-8) analysis was used to verify the cellular proliferation after 24 h and 48 h of culture. Immunohistochemistry was used to confirm the differentiation of the bone marrow cells into neuron-like cells. RESULTS: An NT-3 sustained-release system cross-linked to an acellular spinal cord scaffold was successfully constructed. Sustained-release NT-3 could persist for 35 days and had biological activity for at least 21 days. It could promote the adhesion, proliferation and differentiation of rat bone marrow mesenchymal stem cells. CONCLUSION: As a composite scaffold, an NT-3 sustained-release system cross-linked with an acellular spinal cord scaffold has potential applications for tissue engineering.


Assuntos
Diferenciação Celular/efeitos dos fármacos , Reagentes para Ligações Cruzadas/farmacologia , Células-Tronco Mesenquimais/citologia , Neurotrofina 3/farmacologia , Medula Espinal/fisiologia , Tecidos Suporte/química , Animais , Adesão Celular/efeitos dos fármacos , Contagem de Células , Proliferação de Células/efeitos dos fármacos , Forma Celular/efeitos dos fármacos , Células Cultivadas , Preparações de Ação Retardada/farmacologia , Gânglios Espinais/efeitos dos fármacos , Gânglios Espinais/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Células-Tronco Mesenquimais/efeitos dos fármacos , Ratos Sprague-Dawley , Medula Espinal/efeitos dos fármacos
9.
Muscle Nerve ; 60(5): 613-620, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31397908

RESUMO

INTRODUCTION: The objective of this study is to assess the efficacy of local tacrolimus (FK506) delivery to improve outcomes in the setting of nerve transection injury. METHODS: FK506 embedded poly(lactide-co-caprolactone) films capable of extended, localized release of FK506 were developed. FK506 rate of release testing and bioactivity assay was performed. Mouse sciatic nerve transection and direct repair model was used to evaluate the effect extended, local delivery of FK506 had on nerve regeneration outcomes. RESULTS: Linear release of FK506 was observed for 30 days and released FK506 matched control levels of neurite extension in the dorsal root ganglion assay. Groups treated with local FK506 had greater gastrocnemius muscle weight, foot electromyogram, and number of axons distal of the repair site than non-FK506 groups. DISCUSSION: Results of this study indicate that extended, localized delivery of FK506 to nerve injuries can improve nerve regeneration outcomes in a mouse sciatic nerve transection and repair.


Assuntos
Imunossupressores/farmacologia , Denervação Muscular , Músculo Esquelético/efeitos dos fármacos , Regeneração Nervosa/efeitos dos fármacos , Nervo Isquiático/lesões , Tacrolimo/farmacologia , Animais , Axônios/efeitos dos fármacos , Axônios/patologia , Preparações de Ação Retardada , Eletromiografia , Gânglios Espinais/efeitos dos fármacos , Imunossupressores/administração & dosagem , Camundongos , Músculo Esquelético/patologia , Neuritos/efeitos dos fármacos , Neuritos/patologia , Procedimentos Neurocirúrgicos , Tamanho do Órgão , Traumatismos dos Nervos Periféricos , Poliésteres , Nervo Isquiático/efeitos dos fármacos , Nervo Isquiático/patologia , Nervo Isquiático/cirurgia , Tacrolimo/administração & dosagem
10.
Br J Anaesth ; 123(4): 439-449, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31383364

RESUMO

BACKGROUND: Nerve growth factor (NGF) has been implicated in hyperalgesia by sensitising nociceptors. A role for NGF in modulating myocardial injury through ischaemic nociceptive signalling is plausible. We examined whether inhibition of spinal NGF attenuates myocardial ischaemia-reperfusion injury and explored the underlying mechanisms. METHODS: In adult rats, lentivirus-mediated short-hairpin RNA targeted at reducing NGF gene expression (NGF-shRNA) or a transient receptor potential vanilloid 1 (TRPV1) antagonist (capsazepine) was injected intrathecally before myocardial ischaemia-reperfusion. Infarct size (expressed as the ratio of area at risk) and risk of arrhythmias were quantified. Whole-cell clamp patch electrophysiology was used to record capsaicin currents in primary dorsal root ganglion neurones. The co-expression of substance P (SP) and calcitonin gene-related peptide (CGRP), plus activation of TRPV1, protein kinase B (Akt) and extracellular signal-regulated kinase (ERK) were also quantified. RESULTS: NGF levels increased by 2.95 (0.34)-fold in dorsal root ganglion and 2.12 (0.27)-fold in spinal cord after myocardial ischaemia-reperfusion injury. Intrathecal injection of NGF-shRNA reduced infarct area at risk from 0.58 (0.02) to 0.37 (0.02) (P<0.01) and reduced arrhythmia score from 3.67 (0.33) to 1.67 (0.33) (P<0.01). Intrathecal capsazepine was similarly cardioprotective. NGF-shRNA suppressed expression of SP/CGRP and activation of Akt/ERK and TRPV1 in spinal cord. NGF increased capsaicin current amplitude from 144 (42) to 840 (132) pA (P<0.05), which was blocked by the TRPV1 antagonist 5'-iodoresiniferatoxin. Exogenous NGF enhanced capsaicin-induced Akt/ERK and TRPV1 activation in PC12 neuroendocrine tumour cells in culture. CONCLUSIONS: Spinal NGF contributes to myocardial ischaemia-reperfusion injury by mediating nociceptive signal transmission.


Assuntos
Terapia Genética/métodos , Lentivirus/genética , Traumatismo por Reperfusão Miocárdica/genética , Traumatismo por Reperfusão Miocárdica/prevenção & controle , Fator de Crescimento Neural/genética , RNA Interferente Pequeno/administração & dosagem , RNA Interferente Pequeno/uso terapêutico , Animais , Arritmias Cardíacas/prevenção & controle , Capsaicina/análogos & derivados , Capsaicina/farmacologia , Cardiotônicos/administração & dosagem , Cardiotônicos/uso terapêutico , Gânglios Espinais/efeitos dos fármacos , Gânglios Espinais/metabolismo , Injeções Espinhais , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Infarto do Miocárdio/diagnóstico por imagem , Infarto do Miocárdio/prevenção & controle , Fator de Crescimento Neural/biossíntese , Células PC12 , Técnicas de Patch-Clamp , Ratos , Ratos Sprague-Dawley , Canais de Cátion TRPV/antagonistas & inibidores , Canais de Cátion TRPV/metabolismo
11.
Exp Brain Res ; 237(10): 2645-2651, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31388734

RESUMO

Despite extensive preclinical and clinical investigations, a clinically relevant neuroprotective agent against oxaliplatin-induced peripheral neuropathy, which affects the quality of life following chemotherapy, has not been identified. Epidemiological data suggest that ibuprofen may reduce the risk of neuropathy. Male rats were treated with oxaliplatin (n = 6), oxaliplatin and ibuprofen (n = 5) or vehicle (n = 5) every second day for 15 days. Neuropathy was evaluated using mechanical detection thresholds (MDT) at the hind paw and sensory nerve conduction velocity (SNCV) in the tail nerve at baseline, right after and 3 weeks after the end of treatment. Intraepidermal nerve fibre density (IENFD) was evaluated in the hind paw and inflammation in the dorsal root ganglia 3 weeks after treatment. Inflammation in the dorsal root ganglia was assessed using quantitative real-time RT-PCR (qPCR) of the mRNA levels for the pro-inflammatory cytokines, TNF-α and IL-1ß, and by immunohistochemical staining for Iba1+ macrophages. SNCV was reduced in rats treated with oxaliplatin and with oxaliplatin and ibuprofen compared to control rats 3 weeks after treatment. No differences were found for MDT 3 weeks after treatment. IENFD was reduced in rats treated with oxaliplatin. There was a trend towards up-regulation of TNF-α mRNA levels in rats treated with oxaliplatin and with oxaliplatin and ibuprofen. Morphological changes of Iba1+ macrophages suggested activation, but no differences were found in area fraction or size of macrophage cell bodies. The results did not support a neuroprotective effect of ibuprofen but indicated that inflammation may play a role in oxaliplatin-induced peripheral neuropathy.


Assuntos
Antineoplásicos/farmacologia , Ibuprofeno/farmacologia , Inflamação/tratamento farmacológico , Neuralgia/tratamento farmacológico , Animais , Citocinas/metabolismo , Modelos Animais de Doenças , Gânglios Espinais/efeitos dos fármacos , Masculino , Neuralgia/induzido quimicamente , Ratos Sprague-Dawley
12.
Hypertension ; 74(4): 910-920, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31422690

RESUMO

Hypertension is associated with increased sympathetic activity. A component of this sympathoexcitation may be driven by increased signaling from sensory endings from the heart to the autonomic control areas in the brain. This pathway mediates the so-called cardiac sympathetic afferent reflex, which is also activated by coronary ischemia or other nociceptive stimuli in the heart. The cardiac sympathetic afferent reflex has been shown to be enhanced in the heart failure state and in renal hypertension. However, little is known about its role in the development or progression of hypertension or the phenotype of the sensory endings involved. To investigate this, we used the selective afferent neurotoxin, resiniferatoxin (RTX) to chronically abolish the cardiac sympathetic afferent reflex in 2 models of hypertension; the spontaneous hypertensive rats (SHRs) and AngII (angiotensin II) infusion (240 ng/kg per min). Blood pressure (BP) was measured in conscious animals for 2 to 8 weeks post-RTX. Epidural application of RTX to the T1-T4 spinal segments prevented the further BP increase in 8-week-old SHR and lowered BP in 16-week-old SHR. RTX did not affect BP in Wistar-Kyoto normotensive rats nor in AngII-infused rats. Epicardial application of RTX (50 µg/mL) in 4-week-old SHR prevented the BP increase whereas this treatment does not lower BP in 16-week-old SHR. When RTX was administered into the L2-L5 spinal segments of 16-week-old SHR, no change in BP was observed. These findings indicate that signaling via thoracic afferent nerve fibers may contribute to the hypertension phenotype in the SHR but not in the Ang II infusion model of hypertension.


Assuntos
Pressão Sanguínea/fisiologia , Gânglios Espinais/metabolismo , Coração/inervação , Hipertensão/metabolismo , Canais de Cátion TRPV/agonistas , Angiotensina II , Animais , Pressão Arterial/efeitos dos fármacos , Pressão Arterial/fisiologia , Pressão Sanguínea/efeitos dos fármacos , Diterpenos/farmacologia , Gânglios Espinais/efeitos dos fármacos , Coração/efeitos dos fármacos , Frequência Cardíaca/efeitos dos fármacos , Frequência Cardíaca/fisiologia , Hipertensão/induzido quimicamente , Masculino , Neurotoxinas/farmacologia , Ratos , Ratos Endogâmicos SHR , Ratos Sprague-Dawley , Reflexo/efeitos dos fármacos , Reflexo/fisiologia , Sistema Nervoso Simpático/efeitos dos fármacos , Sistema Nervoso Simpático/metabolismo
13.
Mar Drugs ; 17(8)2019 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-31344776

RESUMO

Conus ateralbus is a cone snail endemic to the west side of the island of Sal, in the Cabo Verde Archipelago off West Africa. We describe the isolation and characterization of the first bioactive peptide from the venom of this species. This 30AA venom peptide is named conotoxin AtVIA (δ-conotoxin-like). An excitatory activity was manifested by the peptide on a majority of mouse lumbar dorsal root ganglion neurons. An analog of AtVIA with conservative changes on three amino acid residues at the C-terminal region was synthesized and this analog produced an identical effect on the mouse neurons. AtVIA has homology with δ-conotoxins from other worm-hunters, which include conserved sequence elements that are shared with δ-conotoxins from fish-hunting Conus. In contrast, there is no comparable sequence similarity with δ-conotoxins from the venoms of molluscivorous Conus species. A rationale for the potential presence of δ-conotoxins, that are potent in vertebrate systems in two different lineages of worm-hunting cone snails, is discussed.


Assuntos
Conotoxinas/química , Caramujo Conus/química , Aminoácidos/genética , Animais , Cabo Verde , Conotoxinas/farmacocinética , Sequência Conservada/genética , Feminino , Gânglios Espinais/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Neurônios/efeitos dos fármacos , Peptídeos/química , Peptídeos/genética , Peptídeos/farmacocinética , Filogenia
14.
Eur J Pharmacol ; 858: 172443, 2019 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-31181208

RESUMO

The role of spinal α5 subunit-containing GABAA (α5-GABAA) receptors in chronic pain is controversial. The purpose of this study was to investigate the participation of spinal α5-GABAA receptors in the reserpine-induced pain model. Reserpine administration induced tactile allodynia and muscle hyperalgesia in female and male rats. Intrathecal injection of L-655,708 and TB 21007 (7 days after the last reserpine injection) decreased tactile allodynia and, at a lesser extent, muscle hyperalgesia in female rats. The effects of these drugs produced a lower antiallodynic and antihyperalgesic effect in male than in female rats. Contrariwise, these drugs produced tactile allodynia and muscle hyperalgesia in naïve rats and these effects were lower in naïve male than female rats. Intrathecal L-838,417 prevented or reversed L-655,708-induced antiallodynia in reserpine-treated female rats. Repeated treatment with α5-GABAA receptor small interfering RNA (siRNA), but not scramble siRNA, reduced reserpine-induced allodynia in female rats. Accordingly, α5-GABAA receptor siRNA induced nociceptive hypersensitivity in naïve female rats. Reserpine enhanced α5-GABAA receptors expression in spinal cord and dorsal root ganglia (DRG), while it increased CD11b (OX-42) and glial fibrillary acidic protein (GFAP) fluorescence intensity in the lumbar spinal cord. In contrast, reserpine diminished K+-Cl- co-transporter 2 (KCC2) protein in the lumbar spinal cord. Data suggest that spinal α5-GABAA receptors play a sex-dependent proallodynic effect in reserpine-treated rats. In contrast, these receptors have a sex-dependent antiallodynic role in naïve rats.


Assuntos
Fibromialgia/complicações , Dor/complicações , Dor/tratamento farmacológico , Receptores de GABA-A/metabolismo , Reserpina/farmacologia , Animais , Astrócitos/efeitos dos fármacos , Astrócitos/patologia , Feminino , Gânglios Espinais/efeitos dos fármacos , Gânglios Espinais/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Hiperalgesia/tratamento farmacológico , Hiperalgesia/metabolismo , Masculino , Microglia/efeitos dos fármacos , Microglia/patologia , Dor/induzido quimicamente , Dor/patologia , Ratos , Ratos Wistar , Medula Espinal/efeitos dos fármacos , Medula Espinal/metabolismo , Simportadores/metabolismo
15.
PLoS One ; 14(6): e0217819, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31167004

RESUMO

Subsets of small-diameter dorsal root ganglia (DRG) neurons detect pruritogenic (itch-causing) and algogenic (pain-causing) stimuli and can be activated or sensitized by chemical mediators. Many of these chemical mediators activate receptors that are coupled to lipid hydrolysis and diacylglycerol (DAG) production. Diacylglycerol kinase iota (DGKI) can phosphorylate DAG and is expressed at high levels in small-diameter mouse DRG neurons. Given the importance of these neurons in sensing pruritogenic and algogenic chemicals, we sought to determine if loss of DGKI impaired responses to itch- or pain-producing stimuli. Using male and female Dgki-knockout mice, we found that in vivo sensitivity to histamine-but not other pruritogens-was enhanced. In contrast, baseline pain sensitivity and pain sensitization following inflammatory or neuropathic injury were equivalent between wild type and Dgki-/- mice. In vitro calcium responses in DRG neurons to histamine was enhanced, while responses to algogenic ligands were unaffected by Dgki deletion. These data suggest Dgki regulates sensory neuron and behavioral responses to histamine, without affecting responses to other pruritogenic or algogenic agents.


Assuntos
Diacilglicerol Quinase/deficiência , Histamina/efeitos adversos , Prurido/induzido quimicamente , Prurido/enzimologia , Animais , Comportamento Animal , Cálcio/farmacologia , Diacilglicerol Quinase/metabolismo , Modelos Animais de Doenças , Feminino , Gânglios Espinais/efeitos dos fármacos , Gânglios Espinais/metabolismo , Inflamação/patologia , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Nociceptividade , Dor/enzimologia , Dor/patologia , Dor/fisiopatologia , Prurido/patologia , Prurido/fisiopatologia , Células Receptoras Sensoriais/efeitos dos fármacos , Células Receptoras Sensoriais/metabolismo , Células Receptoras Sensoriais/patologia
16.
Life Sci ; 232: 116606, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31254586

RESUMO

AIMS: Bupivacaine, a common local anesthetic, can cause neurotoxicity and abnormal neuro-disorders. However, the precise underlying mechanisms have not been fully elucidated. In this study, we investigated the function of lncRNA MALAT1 in the bupivacaine-induced neurotoxicity process. MATERIALS AND METHODS: SH-SY5Y cells and neonatal mouse DRG neurons were cultured in vitro and treated with bupivacaine to establish a neurotoxicity model. Caspase3 activity and cell survival rates were detected to evaluate the function of lncRNA MALAT1. Western blotting was used to detect the expression levels of PDCD4 and cleaved-caspase-3. A dual-luciferase reporter assay was used to explore the potential binding target of lncRNA MALAT1. RESULTS: We found that the expression of lncRNA MALAT1 was upregulated upon exposure to bupivacaine. Knockdown of lncRNA MALAT1 significantly increased the cell death rates, and Caspase3 activity assays revealed that the apoptosis rates were manifestly increased in the MALAT1 downregulation group. In addition, we screened the possible target and found that miR-101-3p is the direct target of MALAT1 using a dual-luciferase reporter assay; these results suggest that lncRNA MALAT1 may function as a decoy to sponge miR-101-3p. Furthermore, we demonstrated that activation of the MALAT1/miR-101-3p/PDCD4 axis protected cells against bupivacaine treatment. CONCLUSION: We elucidated the function and mechanism of MALAT1 in bupivacaine-induced neurotoxicity. Targeting MALAT1 might provide new methods to prevent neurotoxicity.


Assuntos
Proteínas Reguladoras de Apoptose/metabolismo , Bupivacaína/toxicidade , MicroRNAs/metabolismo , Síndromes Neurotóxicas/etiologia , RNA Longo não Codificante/genética , Proteínas de Ligação a RNA/metabolismo , Anestésicos Locais/farmacologia , Animais , Apoptose/efeitos dos fármacos , Proteínas Reguladoras de Apoptose/genética , Linhagem Celular Tumoral , Gânglios Espinais/efeitos dos fármacos , Técnicas de Silenciamento de Genes , Humanos , Camundongos , MicroRNAs/genética , Síndromes Neurotóxicas/genética , Síndromes Neurotóxicas/metabolismo , RNA Longo não Codificante/metabolismo , Proteínas de Ligação a RNA/genética , Regulação para Cima/efeitos dos fármacos
17.
Eur J Pharmacol ; 856: 172408, 2019 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-31129158

RESUMO

Painful diabetic neuropathy (PDN) is a serious symptom that compromises quality of life and remains without effective pharmacological treatment. The transient receptor vanilloid 4 (TRPV4) is a cation-permeable channel implicated in sensory transduction and pain signalling. Therefore, drugs that act on TRPV4 may have therapeutic applications to treat PDN. In the present work, we assessed the effect of the selective TRPV4 channel antagonist HC-067047 on painful neuropathy associated with streptozotocin (STZ)-induced diabetes in mice. STZ-treated animals presented both mechanical and cold allodynia at 6 weeks after diabetes induction. Notably, HC-067047 (1 mg/kg, s.c.) given daily between 2 and 6 weeks after diabetes induction significantly prevented the development of mechanical allodynia. Additionally, both single and repeated treatments with HC-067047 (10 mg/kg, s.c.) significantly reverted established mechanical allodynia induced by STZ. However, HC-067047 was not capable of affecting either thermal cold allodynia or hyperglycemia. Similarly, HC-067047 treatments showed no effect on body weight, temperature, locomotor activity or motor coordination of control mice. Immunohistochemistry assay showed that TRPV4 expression was not different in sciatic nerve, dorsal root ganglia (DRG) or hind paw plantar skin from diabetic and non-diabetic mice, suggesting that HC-067047 acts on constitutive receptors to inhibit mechanical allodynia. Taken together, the data generated in the present study show the potential relevance of using TRPV4 antagonists to treat painful neuropathy associated with diabetes.


Assuntos
Neuropatias Diabéticas/tratamento farmacológico , Hiperalgesia/tratamento farmacológico , Morfolinas/farmacologia , Pirróis/farmacologia , Canais de Cátion TRPV/antagonistas & inibidores , Animais , Temperatura Corporal/efeitos dos fármacos , Peso Corporal/efeitos dos fármacos , Neuropatias Diabéticas/metabolismo , Neuropatias Diabéticas/fisiopatologia , Gânglios Espinais/efeitos dos fármacos , Gânglios Espinais/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Hiperalgesia/metabolismo , Hiperalgesia/fisiopatologia , Locomoção/efeitos dos fármacos , Masculino , Camundongos , Morfolinas/uso terapêutico , Desempenho Psicomotor/efeitos dos fármacos , Pirróis/uso terapêutico , Nervo Isquiático/efeitos dos fármacos , Nervo Isquiático/metabolismo , Canais de Cátion TRPV/metabolismo
18.
Anesth Analg ; 128(6): e84-e87, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31094778

RESUMO

Recent findings from a phase II clinical trial showed analgesic effects of an angiotensin II type-2 receptor (AT2R) antagonist in postherpetic neuralgia patients. This study aimed to investigate whether AT2R antagonism could provide effective analgesia in voluntary measures of unevoked/ongoing pain-like behaviors in mice with experimental neuropathy. Mice were subjected to spared nerve injury to induce neuropathy and tested in 2 operant behavioral tests to measure ongoing mechanical and cold pain hypersensitivities. Systemic administration of an AT2R antagonist provided effective analgesia in these behavioral measures of mechanical and cold pain in spared nerve injury mice, suggesting its effectiveness in neuropathic pain.


Assuntos
Bloqueadores do Receptor Tipo 2 de Angiotensina II/administração & dosagem , Temperatura Baixa , Gânglios Espinais/efeitos dos fármacos , Hiperalgesia/tratamento farmacológico , Neuralgia/tratamento farmacológico , Analgesia , Angiotensina II/metabolismo , Animais , Comportamento Animal , Feminino , Marcha , Imidazóis/administração & dosagem , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Manejo da Dor , Piridinas/administração & dosagem , Receptor Tipo 2 de Angiotensina/metabolismo
19.
Int J Mol Sci ; 20(11)2019 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-31141907

RESUMO

Melatonin is a neurohormone produced and secreted at night by pineal gland. Many effects of melatonin have already been described, for example: Activation of potassium channels in the suprachiasmatic nucleus and inhibition of excitability of a sub-population of neurons of the dorsal root ganglia (DRG). The DRG is described as a structure with several neuronal populations. One classification, based on the repolarizing phase of the action potential (AP), divides DRG neurons into two types: Without (N0) and with (Ninf) inflection on the repolarization phase of the action potential. We have previously demonstrated that melatonin inhibits excitability in N0 neurons, and in the present work, we aimed to investigate the melatonin effects on the other neurons (Ninf) of the DRG neuronal population. This investigation was done using sharp microelectrode technique in the current clamp mode. Melatonin (0.01-1000.0 nM) showed inhibitory activity on neuronal excitability, which can be observed by the blockade of the AP and by the increase in rheobase. However, we observed that, while some neurons were sensitive to melatonin effect on excitability (excitability melatonin sensitive-EMS), other neurons were not sensitive to melatonin effect on excitability (excitability melatonin not sensitive-EMNS). Concerning the passive electrophysiological properties of the neurons, melatonin caused a hyperpolarization of the resting membrane potential in both cell types. Regarding the input resistance (Rin), melatonin did not change this parameter in the EMS cells, but increased its values in the EMNS cells. Melatonin also altered several AP parameters in EMS cells, the most conspicuously changed was the (dV/dt)max of AP depolarization, which is in coherence with melatonin effects on excitability. Otherwise, in EMNS cells, melatonin (0.1-1000.0 nM) induced no alteration of (dV/dt)max of AP depolarization. Thus, taking these data together, and the data of previous publication on melatonin effect on N0 neurons shows that this substance has a greater pharmacological potency on Ninf neurons. We suggest that melatonin has important physiological function related to Ninf neurons and this is likely to bear a potential relevant therapeutic use, since Ninf neurons are related to nociception.


Assuntos
Potenciais de Ação , Depressores do Sistema Nervoso Central/farmacologia , Gânglios Espinais/efeitos dos fármacos , Melatonina/farmacologia , Neurônios/efeitos dos fármacos , Animais , Células Cultivadas , Gânglios Espinais/citologia , Gânglios Espinais/fisiologia , Masculino , Neurônios/fisiologia , Ratos , Ratos Wistar
20.
Cell Mol Neurobiol ; 39(6): 799-808, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31011938

RESUMO

Vincristine is a toxic chemotherapeutic agent which often triggers neuropathic pain through inflammation. Morin isolated from figs (Ficus carica) exerts anti-inflammatory and neuroprotective activities. We investigated whether morin ameliorates vincristine-induced neuropathic pain and the underlying mechanism. Vincristine was injected i.p. for 10 days (day 1-5 and day 8-12). Morin was orally administered every other day from day 1 to 21. The pain behaviors were determined by measuring paw withdrawal threshold (PWT) and paw withdrawal latency (PWL). The axons of sciatic nerves were stained with toluidine blue to study the histological abnormality. Function deficit of sciatic nerves was evaluated by sciatic functional index and the sciatic nerve conduction velocity. Neuronal excitability was assessed electrophysiologically and inflammatory mediators were detected using western blotting in dorsal root ganglia. The vincristine-induced reduction in PWT, PWL, and body weight gain was attenuated by morin. Morin restored the sciatic nerve deficits both histologically and functionally in vincristine-injected rats. The vincristine-induced neuronal hyperexcitability and increase in the expression of IL-6, NF-κB, and pNF-κB were abolished after morin administration. This study suggests that morin treatment suppressed vincristine-induced neuropathic pain by protecting the sciatic nerve and inhibiting inflammation through NF-κB pathway.


Assuntos
Flavonoides/uso terapêutico , NF-kappa B/metabolismo , Neuralgia/induzido quimicamente , Neuralgia/tratamento farmacológico , Fármacos Neuroprotetores/uso terapêutico , Nervo Isquiático/patologia , Transdução de Sinais , Vincristina/efeitos adversos , Animais , Flavonoides/farmacologia , Gânglios Espinais/efeitos dos fármacos , Gânglios Espinais/patologia , Inflamação/patologia , Mediadores da Inflamação/metabolismo , Masculino , Fármacos Neuroprotetores/farmacologia , Ratos Sprague-Dawley , Nervo Isquiático/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos
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