RESUMO
Central post-stroke pain (CPSP) and associated depression remain poorly understood and pharmacological treatments are unsatisfactory. Recently, microglia activation was suggested to be involved in CPSP pathophysiology. The goal of this study was to investigate the effectiveness of a co-ultramicronized combination of N-palmitoylethanolamide and luteolin (PEALut) in a mouse model of thalamic hemorrhage (TH)-induced CPSP. TH was established through the collagenase-IV injection in thalamic ventral-posterolateral-nucleus. PEALut effects in CPSP-associated behaviors were evaluated during a 28-days observation period. We found that repeated administrations of co-ultra PEALut significantly reduced mechanical hypersensitivity after TH, as compared to vehicle, by reducing the early microglial activation in the perilesional site. Moreover, PEALut prevented the development of depressive-like behavior (21 days post-TH). These effects were associated with the restoration of synaptic plasticity in LEC-DG pathway and monoamines levels found impaired in TH mice. Hippocampal MED1 and TrkB expressions were significantly increased in TH compared to sham mice 21 days post-TH, whereas BDNF levels were decreased. PEALut restored MED1/TrkB/BDNF expression in mice. Remarkably, we found significant overexpression of MED1 in the human autoptic brain specimens after stroke, indicating a translational potential of our findings. These results pave the way for better-investigating depression in TH- induced CPSP, together with the involvement of MED1/TrkB/BDNF pathway, proposing PEALut as an adjuvant treatment.
Assuntos
Depressão/metabolismo , Hemorragias Intracranianas/metabolismo , Microglia/metabolismo , Dor/metabolismo , Transdução de Sinais/fisiologia , Tálamo/metabolismo , Animais , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Depressão/etiologia , Hemorragias Intracranianas/complicações , Subunidade 1 do Complexo Mediador/metabolismo , Camundongos , Atividade Motora/fisiologia , Dor/etiologia , Ratos Sprague-Dawley , Receptor trkB/metabolismoRESUMO
Toll-like receptors (TLRs) are key receptors through which infectious and non-infectious challenges act with consequent activation of the inflammatory cascade that plays a critical function in various acute and chronic diseases, behaving as amplification and chronicization factors of the inflammatory response. Previous studies have shown that synthetic analogues of lipid A based on glucosamine with few chains of unsaturated and saturated fatty acids, bind MD-2 and inhibit TLR4 receptors. These synthetic compounds showed antagonistic activity against TLR4 activation in vitro by LPS, but little or no activity in vivo. This study aimed to show the potential use of N-palmitoyl-D-glucosamine (PGA), a bacterial molecule with structural similarity to the lipid A component of LPS, which could be useful for preventing LPS-induced tissue damage or even peripheral neuropathies. Molecular docking and molecular dynamics simulations showed that PGA stably binds MD-2 with a MD-2/(PGA)3 stoichiometry. Treatment with PGA resulted in the following effects: (i) it prevented the NF-kB activation in LPS stimulated RAW264.7 cells; (ii) it decreased LPS-induced keratitis and corneal pro-inflammatory cytokines, whilst increasing anti-inflammatory cytokines; (iii) it normalized LPS-induced miR-20a-5p and miR-106a-5p upregulation and increased miR-27a-3p levels in the inflamed corneas; (iv) it decreased allodynia in peripheral neuropathy induced by oxaliplatin or formalin, but not following spared nerve injury of the sciatic nerve (SNI); (v) it prevented the formalin- or oxaliplatin-induced myelino-axonal degeneration of sciatic nerve. SIGNIFICANCE STATEMENT We report that PGA acts as a TLR4 antagonist and this may be the basis of its potent anti-inflammatory activity. Being unique because of its potency and stability, as compared to other similar congeners, PGA can represent a tool for the optimization of new TLR4 modulating drugs directed against the cytokine storm and the chronization of inflammation.
Assuntos
Analgésicos/uso terapêutico , Anti-Inflamatórios/uso terapêutico , Glicolipídeos/uso terapêutico , Hiperalgesia/prevenção & controle , Ceratite/tratamento farmacológico , Neuralgia/tratamento farmacológico , Receptor 4 Toll-Like/antagonistas & inibidores , Analgésicos/farmacologia , Animais , Anti-Inflamatórios/farmacologia , Sinalização do Cálcio/efeitos dos fármacos , Citocinas/metabolismo , Avaliação Pré-Clínica de Medicamentos , Glicolipídeos/farmacologia , Células HEK293 , Humanos , Hiperalgesia/etiologia , Ceratite/induzido quimicamente , Ceratite/patologia , Lipopolissacarídeos/toxicidade , Antígeno 96 de Linfócito/metabolismo , Masculino , Camundongos , MicroRNAs/genética , Modelos Moleculares , Nociceptores/efeitos dos fármacos , Nociceptores/fisiologia , Conformação Proteica , Células RAW 264.7 , Distribuição Aleatória , Nervo Isquiático/lesões , Canal de Cátion TRPA1/metabolismoRESUMO
The chronic constriction injury (CCI) of the sciatic nerve is a nerve injury-based model of neuropathic pain (NP). Comorbidities of NP such as depression, anxiety, and cognitive deficits are associated with a functional reorganization of the medial prefrontal cortex (mPFC). Here, we have employed an adapted model of CCI by placing one single loose ligature around the sciatic nerve in mice for investigating the alterations in sensory, motor, affective, and cognitive behavior and in electrophysiological and biochemical properties in the prelimbic division (PrL) of the mPFC. Our adapted model of CCI induced mechanical allodynia, motor, and cognitive impairments and anxiety- and depression-like behavior. In the PrL division of mPFC was observed an increase in GABA and a decrease in d-aspartate levels. Moreover an increase in the activity of neurons responding to mechanical stimulation with an excitation, mPFC (+), and a decrease in those responding with an inhibition, mPFC (-), was found. Altogether these findings demonstrate that a single ligature around the sciatic nerve was able to induce sensory, affective, cognitive, biochemical, and functional alterations already observed in other neuropathic pain models and it may be an appropriate and easily reproducible model for studying neuropathic pain mechanisms and treatments.
Assuntos
Ácido Aspártico/metabolismo , Comportamento Animal/fisiologia , Neuralgia/fisiopatologia , Limiar da Dor/fisiologia , Traumatismos dos Nervos Periféricos/fisiopatologia , Nervo Isquiático/lesões , Ácido gama-Aminobutírico/metabolismo , Animais , Encéfalo/metabolismo , Encéfalo/fisiopatologia , Cognição/fisiologia , Masculino , Camundongos , Neuralgia/etiologia , Neuralgia/metabolismo , Medição da Dor , Traumatismos dos Nervos Periféricos/complicações , Traumatismos dos Nervos Periféricos/metabolismo , Estimulação FísicaRESUMO
The mechanisms underlying neuropathic pain are poorly understood. Here we show the unexplored role of the hydroxyl carboxylic acid receptor type 2 (HCAR2) in 2 models of neuropathic pain. We used an oral treatment with dimethyl fumarate and the HCAR2 endogenous ligand ß-hydroxybutyrate (BHB) in wild-type (WT) and HCAR2-null mice. We found an up-regulation of the HCAR2 in the sciatic nerve and the dorsal root ganglia in neuropathic mice. Accordingly, acute and chronic treatment with dimethylfumarate (DMF) and BHB reduced the tactile allodynia. This effect was completely lost in the HCAR2-null mice after a 2-d starvation protocol, in which the BHB reached the concentration able to activate the HCAR2-reduced tactile allodynia in female WT mice, but not in the HCAR2-null mice. Finally, we showed that chronic treatment with DMF reduced the firing of the ON cells (cells responding with an excitation after noxious stimulation) of the rostral ventromedial medulla. Our results pave the way for investigating the mechanisms by which HCAR2 regulates neuropathic pain plasticity.-Boccella, S., Guida, F., De Logu, F., De Gregorio, D., Mazzitelli, M., Belardo, C., Iannotta, M., Serra, N., Nassini, R., de Novellis, V., Geppetti, P., Maione, S., Luongo, L. Ketones and pain: unexplored role of hydroxyl carboxylic acid receptor type 2 in the pathophysiology of neuropathic pain.
Assuntos
Cetonas/metabolismo , Neuralgia/fisiopatologia , Receptores Acoplados a Proteínas G/fisiologia , Ácido 3-Hidroxibutírico/administração & dosagem , Ácido 3-Hidroxibutírico/metabolismo , Potenciais de Ação , Animais , Glicemia/metabolismo , Fumarato de Dimetilo/administração & dosagem , Feminino , Imunofluorescência , Gânglios Espinais/fisiopatologia , Cetonas/sangue , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Microscopia Confocal , Neuralgia/metabolismo , Receptores Acoplados a Proteínas G/administração & dosagem , Receptores Acoplados a Proteínas G/genética , Inanição , Regulação para CimaRESUMO
Recent evidence points to the gut microbiota as a regulator of brain and behavior, although it remains to be determined if gut bacteria play a role in chronic pain. The endocannabinoid system is implicated in inflammation and chronic pain processing at both the gut and central nervous system (CNS) levels. In the present study, we used low Vitamin D dietary intake in mice and evaluated possible changes in gut microbiota, pain processing and endocannabinoid system signaling. Vitamin D deficiency induced a lower microbial diversity characterized by an increase in Firmicutes and a decrease in Verrucomicrobia and Bacteroidetes. Concurrently, vitamin D deficient mice showed tactile allodynia associated with neuronal hyperexcitability and alterations of endocannabinoid system members (endogenous mediators and their receptors) at the spinal cord level. Changes in endocannabinoid (anandamide and 2-arachidonoylglycerol) levels were also observed in the duodenum and colon. Remarkably, the anti-inflammatory anandamide congener, palmitoylethanolamide, counteracted both the pain behaviour and spinal biochemical changes in vitamin D deficient mice, whilst increasing the levels of Akkermansia, Eubacterium and Enterobacteriaceae, as compared with vehicle-treated mice. Finally, induction of spared nerve injury in normal or vitamin D deficient mice was not accompanied by changes in gut microbiota composition. Our data suggest the existence of a link between Vitamin D deficiency - with related changes in gut bacterial composition - and altered nociception, possibly via molecular mechanisms involving the endocannabinoid and related mediator signaling systems.
Assuntos
Dor Crônica , Microbioma Gastrointestinal , Deficiência de Vitamina D , Animais , Endocanabinoides , Inflamação , Camundongos , Deficiência de Vitamina D/complicaçõesRESUMO
Neuropathic pain is a pathological condition induced by a lesion or disease affecting the somatosensory system, with symptoms like allodynia and hyperalgesia. It has a multifaceted pathogenesis as it implicates several molecular signaling pathways involving peripheral and central nervous systems. Affective and cognitive dysfunctions have been reported as comorbidities of neuropathic pain states, supporting the notion that pain and mood disorders share some common pathogenetic mechanisms. The understanding of these pathophysiological mechanisms requires the development of animal models mimicking, as far as possible, clinical neuropathic pain symptoms. Among them, the Spared Nerve Injury (SNI) model has been largely characterized in terms of behavioral and functional alterations. This model is associated with changes in neuronal firing activity at spinal and supraspinal levels, and induces late neuropsychiatric disorders (such as anxious-like and depressive-like behaviors, and cognitive impairments) comparable to an advanced phase of neuropathy. The goal of this review is to summarize current findings in preclinical research, employing the SNI model as a tool for identifying pathophysiological mechanisms of neuropathic pain and testing pharmacological agent.
Assuntos
Comportamento Animal/fisiologia , Encéfalo/fisiopatologia , Modelos Animais de Doenças , Fenômenos Eletrofisiológicos/fisiologia , Neuralgia/fisiopatologia , Traumatismos dos Nervos Periféricos/fisiopatologia , Animais , Encéfalo/metabolismo , Encéfalo/patologia , Humanos , Neuralgia/metabolismo , Neuralgia/patologia , Limiar da Dor , Traumatismos dos Nervos Periféricos/metabolismo , Traumatismos dos Nervos Periféricos/patologiaRESUMO
Chronic pain is associated with cognitive deficits. Palmitoylethanolamide (PEA) has been shown to ameliorate pain and pain-related cognitive impairments by restoring glutamatergic synapses functioning in the spared nerve injury (SNI) of the sciatic nerve in mice. SNI reduced mechanical and thermal threshold, spatial memory and LTP at the lateral entorhinal cortex (LEC)-dentate gyrus (DG) pathway. It decreased also postsynaptic density, volume and dendrite arborization of DG and increased the expression of metabotropic glutamate receptor 1 and 7 (mGluR1 and mGluR7), of the GluR1, GluR1s845 and GluR1s831 subunits of AMPA receptor and the levels of glutamate in the DG. The level of the endocannabinoid 2-arachidonoylglycerol (2-AG) was instead increased in the LEC. Chronic treatment with PEA, starting from when neuropathic pain was fully developed, was able to reverse mechanical allodynia and thermal hyperalgesia, memory deficit and LTP in SNI wild type, but not in PPARα null, mice. PEA also restored the level of glutamate and the expression of phosphorylated GluR1 subunits, postsynaptic density and neurogenesis. Altogether, these results suggest that neuropathic pain negatively affects cognitive behavior and related LTP, glutamatergic synapse and synaptogenesis in the DG. In these conditions PEA treatment alleviates pain and cognitive impairment by restoring LTP and synaptic maladaptative changes in the LEC-DG pathway. These outcomes open new perspectives for the use of the N-acylethanolamines, such as PEA, for the treatment of neuropathic pain and its central behavioural sequelae.
Assuntos
Disfunção Cognitiva/tratamento farmacológico , Giro Denteado/efeitos dos fármacos , Córtex Entorrinal/efeitos dos fármacos , Homocisteína/análogos & derivados , Hiperalgesia/tratamento farmacológico , Potenciação de Longa Duração/efeitos dos fármacos , Neuralgia/tratamento farmacológico , Animais , Disfunção Cognitiva/etiologia , Homocisteína/administração & dosagem , Camundongos Endogâmicos C57BL , Vias Neurais/efeitos dos fármacos , Neuralgia/complicações , Neurônios/efeitos dos fármacos , Neurônios/ultraestrutura , Traumatismos dos Nervos Periféricos/complicações , Densidade Pós-Sináptica/efeitos dos fármacos , Densidade Pós-Sináptica/ultraestrutura , Receptores de AMPA/metabolismo , Nervo Isquiático/lesõesRESUMO
This study sought to determine the possible detrimental effects of several low- or non-caloric sweeteners on endothelial progenitor cells (EPCs), inflammation and behavioural changes in mice. C57BL/6 male mice received low and high dose of natural and artificial sweeteners for 4 weeks. EPCs, physical and biochemical variables, inflammation and behavioural changes were evaluated. A significant reduction of about 25% of EPCs was found when mice received a moderate amount of all sweeteners (p < .05). This reduction was more strongly significant when a double dose of glucose, aspartame, rebaudioside A and cyclamate (p < .005) in comparison to fructose and sucrose (p < .05) was administered. During inflammation carrageenan-induced, all sweeteners produced a significant increase of EPCs compared to the control group (p < .05). Consumption of glucose and sugar substitutes affect mouse EPC number according to the absence or presence of an inflammatory status, but does not induce detrimental effects on inflammation and behavioural changes.
Assuntos
Comportamento Animal/efeitos dos fármacos , Células Progenitoras Endoteliais/efeitos dos fármacos , Inflamação/tratamento farmacológico , Edulcorantes/farmacologia , Animais , Ansiedade , Pressão Sanguínea/efeitos dos fármacos , Peso Corporal , Carragenina/efeitos adversos , Comportamento Compulsivo , Diterpenos do Tipo Caurano/farmacologia , Frutose , Glucose , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Modelos Animais , Comportamento Obsessivo , Soro/química , Memória Espacial/efeitos dos fármacos , SacaroseRESUMO
This study investigated whether metabotropic glutamate receptor (mGluR) 5 and 8 are involved in the effect of ultramicronizedpalmitoylethanolamide (um-PEA) on the cognitive behavior and long term potentiation (LTP) at entorhinal cortex (LEC)-dentate gyrus (DG) pathway in mice rendered neuropathic by the spare nerve injury (SNI). SNI reduced discriminative memory and LTP. Um-PEA treatment started after the development of neuropathic pain had no effects in sham mice, whereas it restored cognitive behavior and LTP in SNI mice. 2-Methyl-6-(phenylethynyl) pyridine (MPEP), a selective mGluR5 antagonist, improved cognition in SNI mice and produced a chemical long term depression of the field excitatory postsynaptic potentials (fEPSPs) in sham and SNI mice. After theta burst stimulation (TBS) MPEP restored LTP in SNI mice. In combination with PEA, MPEP antagonized the PEA effect on discriminative memory and decreased LTP in SNI mice. The (RS)-4-(1-amino-1-carboxyethyl)phthalic acid (MDCPG), a selective mGluR8 antagonist, did not affect discriminative memory, but it induced a chemical LTP and prevented the enhancement of fEPSPs after TBS in SNI mice which were treated or not treated with PEA. The effect of PEA on LTP and cognitive behavior was modulated by mGluR5 and mGluR8. In particular in the SNI conditions, the mGluR5 blockade facilitated memory and LTP, but prevented the beneficial effects of PEA on discriminative memory while the mGluR8 blockade, which was ineffective in itself, prevented the favorable action of the PEA on LTP. Thus, although their opposite roles (excitatory/inhibitory of the two receptor subtypes on the glutamatergic system), they appeared to be required for the neuroprotective effect of PEA in conditions of neuropathic pain.
Assuntos
Etanolaminas/administração & dosagem , Neuralgia/tratamento farmacológico , Ácidos Palmíticos/administração & dosagem , Traumatismos dos Nervos Periféricos/tratamento farmacológico , Receptor de Glutamato Metabotrópico 5/metabolismo , Receptores de Glutamato Metabotrópico/metabolismo , Amidas , Animais , Giro Denteado/efeitos dos fármacos , Giro Denteado/metabolismo , Modelos Animais de Doenças , Etanolaminas/farmacologia , Potenciais Pós-Sinápticos Excitadores/efeitos dos fármacos , Humanos , Potenciação de Longa Duração/efeitos dos fármacos , Masculino , Memória/efeitos dos fármacos , Camundongos , Neuralgia/etiologia , Neuralgia/metabolismo , Córtex Olfatório/efeitos dos fármacos , Córtex Olfatório/metabolismo , Ácidos Palmíticos/farmacologia , Traumatismos dos Nervos Periféricos/complicações , Traumatismos dos Nervos Periféricos/metabolismo , Piridinas/administração & dosagem , Piridinas/farmacologiaRESUMO
D-Aspartate (D-Asp) is a free D-amino acid detected in multiple brain regions and putative precursor of endogenous N-methyl-D-aspartate (NMDA) acting as agonist at NMDA receptors. In this study, we investigated whether D-Asp (20 mM) in drinking solution for 1 month affects pain responses and pain-related emotional, and cognitive behaviour in a model of neuropathic pain induced by the spared nerve injury (SNI) of the sciatic nerve in mice. SNI mice developed mechanical allodynia and motor coordination impairment 30 days after SNI surgery. SNI mice showed cognitive impairment, anxiety and depression-like behaviour, reduced sociability in the three chamber sociability paradigm, increased expression of NR2B subunit of NMDA receptor and Homer 1a in the medial prefrontal cortex (mPFC). The expression of (post synaptic density) PSD-95 and Shank 1was instead unaffected in the mPFC of the SNI mice. Treatment with D-Asp drinking solution, started right after the SNI (day 0), alleviated mechanical allodynia, improved cognition and motor coordination and increased social interaction. D-Asp also restored the levels of extracellular D-Asp, Homer 1a and NR2B subunit of the NMDA receptor to physiological levels and reduced Shank1 and PSD-95 protein levels in the mPFC. Amitriptyline, a tricyclic antidepressant used also to alleviate neuropathic pain in humans, reverted mechanical allodynia and cognitive impairment, and unlike D-Asp, was effective in reducing depression and anxiety-like behaviour in the SNI mice and increased PSD protein level. Altogether these findings demonstrate that D-Asp improves sensorial, motor and cognitive-like symptoms related to chronic pain possibly through glutamate neurotransmission normalization in neuropathic mice.
Assuntos
Ácido Aspártico/farmacologia , Disfunção Cognitiva/tratamento farmacológico , Proteínas de Arcabouço Homer/metabolismo , Neuralgia/tratamento farmacológico , Córtex Pré-Frontal/metabolismo , Receptores de N-Metil-D-Aspartato/metabolismo , Nervo Isquiático/lesões , Animais , Disfunção Cognitiva/metabolismo , Disfunção Cognitiva/patologia , Proteína 4 Homóloga a Disks-Large/metabolismo , Humanos , Hiperalgesia/tratamento farmacológico , Hiperalgesia/metabolismo , Hiperalgesia/patologia , Masculino , Camundongos , Neuralgia/metabolismo , Neuralgia/patologia , Córtex Pré-Frontal/patologia , Nervo Isquiático/metabolismo , Nervo Isquiático/patologiaRESUMO
BACKGROUND: Despite extensive studies on the neurobiological correlates of traumatic brain injury (TBI), little is known about its molecular determinants on long-term consequences, such as dementia and Alzheimer's disease (AD). METHODS: Here, we carried out behavioural studies and an extensive biomolecular analysis, including inflammatory cytokines, gene expression and the combination of LC-HRMS and MALDI-MS Imaging to elucidate the targeted metabolomics and lipidomics spatiotemporal alterations of brains from wild-type and APP-SWE mice, a genetic model of AD, at the presymptomatic stage, subjected to mild TBI. RESULTS: We found that brain injury does not affect cognitive performance in APP-SWE mice. However, we detected an increase of key hallmarks of AD, including Aß1-42 levels and BACE1 expression, in the cortices of traumatized transgenic mice. Moreover, significant changes in the expanded endocannabinoid (eCB) system, or endocannabinoidome (eCBome), occurred, including increased levels of the endocannabinoid 2-AG in APP-SWE mice in both the cortex and hippocampus, and N-acylserotonins, detected for the first time in the brain. The gene expression of enzymes for the biosynthesis and inactivation of eCBs and eCB-like mediators, and some of their main molecular targets, also underwent significant changes. We also identified the formation of heteromers between cannabinoid 1 (CB1) and serotonergic 2A (5HT2A) receptors, whose levels increased in the cortex of APP-SWE mTBI mice, possibly contributing to the exacerbated pathophysiology of AD induced by the trauma. CONCLUSIONS: Mild TBI induces biochemical changes in AD genetically predisposed mice and the eCBome may play a role in the pathogenetic link between brain injury and neurodegenerative disorders also by interacting with the serotonergic system.
Assuntos
Doença de Alzheimer , Disfunção Cognitiva , Endocanabinoides , Camundongos Transgênicos , Animais , Doença de Alzheimer/metabolismo , Doença de Alzheimer/genética , Camundongos , Endocanabinoides/metabolismo , Disfunção Cognitiva/metabolismo , Serotonina/metabolismo , Biomarcadores/metabolismo , Masculino , Concussão Encefálica/metabolismo , Modelos Animais de Doenças , Camundongos Endogâmicos C57BL , Encéfalo/metabolismo , Precursor de Proteína beta-Amiloide/genética , Precursor de Proteína beta-Amiloide/metabolismo , Sintomas Prodrômicos , Peptídeos beta-Amiloides/metabolismoRESUMO
There is a growing evidence suggesting the association of vitamin D deficiency (VDD) and cognitive impairment. In this study we evaluated the possible involvement of gut microbiota in the cognitive impairments mediated by VDD and investigated the effects of pharmacological treatment with the oxazoline derivative of the aliamide palmitoylethanolamide, 2-Pentadecyl-2-oxazoline (PEA-OXA). Mice were submitted to behavioural, biochemical and electrophysiological analysis to assess whether their vitamin D status affected cognitive performance together with gut microbiota composition. In VDD mice we found cognitive malfunctioning associated with reduced neuroplasticity, indicated by impaired long term potentiation, and neuroinflammation at the hippocampal level. Importantly, PEA-OXA counteracted the cognitive impairments and modified the biochemical and functional changes induced by VDD. Additionally, PEA-OXA treatment enhanced gut microbiota diversity, which tended to be decreased by VDD only in female mice, elevated the relative abundance of lactic and butyric acid-producing families, i.e. Aerococcaceae and Butyricicoccaceae, and reversed the VDD-induced decrease of butyrate-producing beneficial genera, such as Blautia in female mice, and Roseburia in male mice. These data provide novel insights for a better understanding of the cognitive decline induced by VDD and related gut dysbiosis and its potential therapeutic treatment.
Assuntos
Disfunção Cognitiva , Microbioma Gastrointestinal , Deficiência de Vitamina D , Animais , Microbioma Gastrointestinal/efeitos dos fármacos , Disfunção Cognitiva/tratamento farmacológico , Disfunção Cognitiva/metabolismo , Disfunção Cognitiva/etiologia , Masculino , Feminino , Camundongos , Deficiência de Vitamina D/complicações , Deficiência de Vitamina D/tratamento farmacológico , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Camundongos Endogâmicos C57BL , Etanolaminas/farmacologia , Etanolaminas/metabolismo , Disbiose , Amidas/farmacologia , Cognição/efeitos dos fármacos , Modelos Animais de DoençasRESUMO
Alzheimer's disease (AD) is a neurodegenerative form of dementia characterized by the loss of synapses and a progressive decline in cognitive abilities. Among current treatments for AD, acetylcholinesterase (AChE) inhibitors have efficacy limited to symptom relief, with significant side effects and poor compliance. Pharmacological agents that modulate the activity of type-2 cannabinoid receptors (CB2R) of the endocannabinoid system by activating or blocking them have also been shown to be effective against neuroinflammation. Herein, we describe the design, synthesis, and pharmacological effects in vitro and in vivo of dual-acting compounds that inhibit AChE and butyrylcholinesterase (BChE) and target CB2R. Within the investigated series, compound 4g proved to be the most promising. It achieved IC50 values in the low micromolar to submicromolar range against both human cholinesterase isoforms while antagonizing CB2R with Ki of 31 nM. Interestingly, 4g showed neuroprotective effects on the SH-SY5Y cell line thanks to its ability to prevent oxidative stress-induced cell toxicity and reverse scopolamine-induced amnesia in the Y-maze forced alternation test in vivo.
Assuntos
Doença de Alzheimer , Disfunção Cognitiva , Neuroblastoma , Fármacos Neuroprotetores , Humanos , Butirilcolinesterase/metabolismo , Acetilcolinesterase/metabolismo , Fármacos Neuroprotetores/farmacologia , Fármacos Neuroprotetores/uso terapêutico , Receptores de Canabinoides , Inibidores da Colinesterase/farmacologia , Inibidores da Colinesterase/uso terapêutico , Doença de Alzheimer/metabolismo , Disfunção Cognitiva/tratamento farmacológico , Simulação de Acoplamento Molecular , Relação Estrutura-AtividadeRESUMO
BACKGROUND: Integrins, important extracellular matrix (ECM) receptor proteins, are affected by inflammation and can participate in the maintenance of many painful conditions. Although they are ubiquitous and changeable across all cell types, the roles of these cell adhesion molecules in pathological pain have not been fully explored. OBJECTIVE: We evaluated the effects of the subcutaneous injection of lebecetin, a C-type lectin isolated from Macrovipera lebetina snake venom, previously reported to inhibit α5ß1 and αv integrin activity, on different components of inflammation induced by the formalin administration in the hind paw of mice. METHODS: The formalin-induced nocifensive behavior, edema, and histopathological changes in the hind paw associated with cytokine, iNOS, and COX2 expression, nociceptive-specific neuron activity, and microglial activation analysis in the spinal cord were evaluated in mice receiving vehicle or lebecetin pretreatment. RESULTS: Lebecetin inhibited the nocifensive responses in the formalin test, related edema, and cell infiltration in the injected paw in a biphasic, hormetic-like, and dose-dependent way. According to that hormetic trend, a reduction in pro-inflammatory cytokines IL-6, IL-8, and TNF-alpha and upregulation of the anti-inflammatory cytokine IL-10 in the spinal cord were found with the lowest doses of lebecetin. Moreover, COX2 and iNOS expression in serum and spinal cord followed the same biphasic pattern of cytokines. Finally, nociceptive neurons sensitization and activated microglia were normalized in the dorsal horn of the spinal cord by lebecetin. CONCLUSION: These findings implicate specific roles of integrins in inflammation and tonic pain, as well as in the related central nervous system sequelae.
RESUMO
ABSTRACT: Neuropathic pain has long-term consequences in affective and cognitive disturbances, suggesting the involvement of supraspinal mechanisms. In this study, we used the spared nerve injury (SNI) model to characterize the development of sensory and aversive components of neuropathic pain and to determine their electrophysiological impact across prefrontal cortex and limbic regions. Moreover, we evaluated the regulation of several genes involved in immune response and inflammation triggered by SNI. We showed that SNI led to sensorial hypersensitivity (cold and mechanical stimuli) and depressive-like behavior lasting 12 months after nerve injury. Of interest, changes in nonemotional cognitive tasks (novel object recognition and Y maze) showed in 1-month SNI mice were not evident normal in the 12-month SNI animals. In vivo electrophysiology revealed an impaired long-term potentiation at prefrontal cortex-nucleus accumbens core pathway in both the 1-month and 12-month SNI mice. On the other hand, a reduced neural activity was recorded in the lateral entorhinal cortex-dentate gyrus pathway in the 1-month SNI mice, but not in the 12-month SNI mice. Finally, we observed the upregulation of specific genes involved in immune response in the hippocampus of 1-month SNI mice, but not in the 12-month SNI mice, suggesting a neuroinflammatory response that may contribute to the SNI phenotype. These data suggest that distinct brain circuits may drive the psychiatric components of neuropathic pain and pave the way for better investigation of the long-term consequences of peripheral nerve injury for which most of the available drugs are to date unsatisfactory.
Assuntos
Neuralgia , Traumatismos dos Nervos Periféricos , Animais , Modelos Animais de Doenças , Hipocampo/metabolismo , Hiperalgesia/metabolismo , Potenciação de Longa Duração , Camundongos , Neuralgia/genética , Neuralgia/metabolismo , Plasticidade Neuronal , Traumatismos dos Nervos Periféricos/metabolismoRESUMO
Chronic social isolation generates a persistent state of stress associated with obesity along with some neuro-endocrine disorders and central behavioral sequelae (eg anxiety, depression, aggression, and allodynia). In this study, we evaluated the effect of social isolation on body weight, depressive- and anxious-aggressive-like behavior, as well as on phenotypic changes of adipocytes from visceral adipose tissue of control (group-housed) or socially isolated (single-housed) male mice. The effect of treatment with pentadecyl-2-oxazoline (PEA-OXA), a natural alpha2 antagonist and histamine H3 protean partial agonist, on these alterations was also evaluated. Single or group-housed mice treated with vehicle or PEA-OXA underwent body weight, mechanical allodynia, anxious-, depressive- and aggressive-like behavior measurements. Proliferation rate, apoptosis, senescence, expression of fat lineage genes, lipid droplets and proinflammatory cytokines were measured on white adipose tissue adipocytes from group- or single-housed mice. Single housed mice developed weight gain, mechanical allodynia at the von Frey test, aggressiveness in the resident intruder test, depression- and anxiety-like behavior in the tail suspension and hole drop tests, respectively. Single housed mice receiving PEA-OXA showed a general resolution of both, physical-metabolic and behavioral alterations associated with social isolation. Furthermore, adipocytes from the adipose tissue of socially isolated mice showed an evident inflamed phenotype (i.e. a reduced rate of proliferation, apoptosis, senescence, and ROS hyper-production together with an increased expression of IL-1ß, IL-10, IL-17, and TNF-α and a decrease of IL-6). The treatment with PEA-OXA on adipocytes from single housed mice produced a protective/anti-inflammatory phenotype with an increased expression of brown adipose tissue biomarker. This study confirms that persistent stress caused by social isolation predisposes to obesity and neuropsychiatric disorders. PEA-OXA, through its multi-target activity on alpha2 adrenoceptor and histamine H3 receptors, which have recently aroused great interest in the neuropsychiatric field, reduces weight gain, systemic pro-inflammatory state, allodynia, and affective disorders associated with social isolation.
Assuntos
Hiperalgesia , Isolamento Social , Tecido Adiposo , Animais , Peso Corporal , Hiperalgesia/tratamento farmacológico , Masculino , Camundongos , Obesidade , Oxazóis , Aumento de PesoRESUMO
The 2-amino-4-(3-hydroxy-5-methylisoxazol-4-yl)-butyric acid, homo-AMPA, an analog of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and 2-aminoadipic acid, has shown no activity towards ionotropic and metabotropic glutamate 1, 2, 3, 4, 5, and 7 receptors (mGluR1-7), agonist activity at mGluR6 while the activity at mGluR8 was never investigated. The effect of homo-AMPA on pain control has been never investigated. In this study we evaluated the effect of intra-ventrolateral periaqueductal grey (VL PAG) microinjections of homo-AMPA on pain responses and the activity of pain-responding neurons of the rostral ventromedial medulla (RVM), the "pronociceptive" ON cells, and the "antinociceptive" OFF cells. The study was performed in control and diabetic neuropathic mice. Homo-AMPA decreased mechanical allodynia in diabetic neuropathic mice. Homo-AMPA increased also the latency to tail-flick, decreased the ongoing activity, the pain stimulus-evoked burst of firing, and the duration of the burst of the ON cells in both, control and neuropathic mice. Homo-AMPA also increased the ongoing activity, decreased and delayed the pause of the OFF cells in control mice. Unlike the retina, we did not find the transcript and protein for mGluR6 in the VL PAG. Alpha-methyl-serine-O-phosphate, a group III mGluRs antagonist, blocked the anti-allodynic effect of homo-AMPA. Considering the absence of both, mGluR6 in VL-PAG and homo-AMPA activity at mGluR4 and mGluR7 at the dose used, mGluR8 could be the target on which homo-AMPA produces the observed effects. The target of homo-AMPA capable of evoking analgesia at a very low dose and in conditions of diabetic neuropathy deserves further consideration.
Assuntos
Diabetes Mellitus , Neuropatias Diabéticas , Animais , Neuropatias Diabéticas/tratamento farmacológico , Neuropatias Diabéticas/metabolismo , Hiperalgesia/metabolismo , Bulbo , Camundongos , Dor/metabolismo , Substância Cinzenta Periaquedutal , Ratos , Ratos Wistar , Ácido alfa-Amino-3-hidroxi-5-metil-4-isoxazol Propiônico/análogos & derivados , Ácido alfa-Amino-3-hidroxi-5-metil-4-isoxazol Propiônico/farmacologiaRESUMO
The mammalian brain stores and distinguishes among episodic memories, i.e. memories formed during the personal experience, through a mechanism of pattern separation computed in the hippocampal dentate gyrus. Decision-making for food-related behaviors, such as the choice and intake of food, might be affected in obese subjects by alterations in the retrieval of episodic memories. Adult neurogenesis in the dentate gyrus regulates the pattern separation. Several molecular factors affect adult neurogenesis and exert a critical role in the development and plasticity of newborn neurons. Orexin-A/hypocretin-1 and downstream endocannabinoid 2-arachidonoylglycerol signaling are altered in obese mice. Here, we show that excessive orexin-A/2-arachidonoylglycerol/cannabinoid receptor type-1 signaling leads to the dysfunction of adult hippocampal neurogenesis and the subsequent inhibition of plasticity and impairment of pattern separation. By inhibiting orexin-A action at orexin-1 receptors we rescued both plasticity and pattern separation impairment in obese mice, thus providing a molecular and functional mechanism to explain alterations in episodic memory in obesity.
Assuntos
Endocanabinoides/metabolismo , Hipocampo/crescimento & desenvolvimento , Neurogênese , Plasticidade Neuronal , Obesidade/metabolismo , Obesidade/psicologia , Orexinas/metabolismo , Animais , Feminino , Hipocampo/metabolismo , Hipocampo/fisiopatologia , Humanos , Masculino , Memória Episódica , Camundongos , Camundongos Obesos , Neurônios/citologia , Neurônios/metabolismo , Obesidade/genética , Obesidade/fisiopatologia , Receptores de Orexina/genética , Receptores de Orexina/metabolismo , Receptor CB1 de Canabinoide/genética , Receptor CB1 de Canabinoide/metabolismo , Transdução de SinaisRESUMO
Neuropathic pain (NP) remains an untreatable disease due to the complex pathophysiology that involves the whole pain neuraxis including the forebrain. Sensory dysfunctions such as allodynia and hyperalgesia are only part of the symptoms associated with neuropathic pain that extend to memory and affectivity deficits. The development of multi-target molecules might be a promising therapeutic strategy against the symptoms associated with NP. 2-pentadecyl-2-oxazoline (PEA-OXA) is a plant-derived agent, which has shown effectiveness against chronic pain and associated neuropsychiatric disorders. The molecular mechanisms by which PEA-OXA exerts its effects are, however, only partially known. In the current study, we show that PEA-OXA, besides being an alpha2 adrenergic receptor antagonist, also acts as a modulator at histamine H3 receptors, and report data on its effects on sensory, affective and cognitive symptoms associated with the spared nerve injury (SNI) model of neuropathic pain in mice. Treatment for 14 days with PEA-OXA after the onset of the symptoms associated with neuropathic pain resulted in the following effects: (i) allodynia was decreased; (ii) affective/cognitive impairment associated with SNI (depression, spatial, and working memories) was counteracted; (iii) long-term potentiation in vivo in the lateral entorhinal cortex-dentate gyrus (perforant pathway, LPP) was ameliorated, (iv) hippocampal glutamate, GABA, histamine, norepinephrine and dopamine level alterations after peripheral nerve injury were reversed, (v) expression level of the TH positive neurons in the Locus Coeruleus were normalized. Thus, a 16-day treatment with PEA-OXA alleviates the sensory, emotional, cognitive, electrophysiological and neurochemical alterations associated with SNI-induced neuropathic pain.
Assuntos
Comportamento Animal , Depressão/complicações , Transtornos da Memória/complicações , Transtornos da Memória/tratamento farmacológico , Neuralgia/tratamento farmacológico , Oxazóis/uso terapêutico , Receptores Adrenérgicos alfa 2/metabolismo , Receptores Histamínicos H3/metabolismo , Sequência de Aminoácidos , Animais , Ansiedade/complicações , Ansiedade/fisiopatologia , Células COS , Chlorocebus aethiops , Cognição/efeitos dos fármacos , Giro Denteado/efeitos dos fármacos , Giro Denteado/metabolismo , Giro Denteado/fisiopatologia , Depressão/tratamento farmacológico , Depressão/fisiopatologia , Córtex Entorrinal/efeitos dos fármacos , Córtex Entorrinal/metabolismo , Córtex Entorrinal/fisiopatologia , Ácido Glutâmico/metabolismo , Humanos , Hiperalgesia/complicações , Hiperalgesia/fisiopatologia , Locus Cerúleo/efeitos dos fármacos , Locus Cerúleo/metabolismo , Potenciação de Longa Duração/efeitos dos fármacos , Masculino , Transtornos da Memória/fisiopatologia , Camundongos Endogâmicos C57BL , Neuralgia/metabolismo , Norepinefrina/metabolismo , Oxazóis/farmacologia , Receptores Histamínicos H3/química , Homologia Estrutural de Proteína , Ácido gama-Aminobutírico/metabolismoRESUMO
The two most important and studied phytocannabinoids present in Cannabis sativa L. are undoubtedly cannabidiol (CBD), a non-psychotropic compound, but with other pharmacological properties, and Δ9-tetrahydrocannabinol (Δ9-THC), which instead possesses psychotropic activity and is responsible for the recreative use of hemp. Recently, the homolog series of both CBDs and THCs has been expanded by the isolation in a medicinal cannabis variety of four new phytocannabinoids possessing on the resorcinyl moiety a butyl-(in CBDB and Δ9-THCB) and a heptyl-(in CBDP and Δ9-THCP) aliphatic chain. In this work we report a new series of phytocannabinoids that fills the gap between the pentyl and heptyl homologs of CBD and Δ9-THC, bearing a n-hexyl side chain on the resorcinyl moiety that we named cannabidihexol (CBDH) and Δ9-tetrahydrocannabihexol (Δ9-THCH), respectively. However, some cannabinoids with the same molecular formula and molecular weight of CBDH and Δ9-THCH have been already identified and reported as monomethyl ether derivatives of the canonical phytocannabinoids, namely cannabigerol monomethyl ether (CBGM), cannabidiol monomethyl ether (CBDM) and Δ9-tetrahydrocannabinol monomethyl ether (Δ9-THCM). The unambiguously identification in cannabis extract of the n-hexyl homologues of CBD and Δ9-THC different from the corresponding methylated isomers (CBDM, CBGM and Δ9-THCM) was achieved by comparison of the retention time, molecular ion, and fragmentation spectra with those of the authentic standards obtained via stereoselective synthesis, and a semi-quantification of these cannabinoids in the FM2 medical cannabis variety was provided. Conversely, no trace of Δ9-THCM was detected. Moreover, CBDH was isolated by semipreparative HPLC and its identity was confirmed by comparison with the spectroscopic data of the corresponding synthetic standard. Thus, the proper recognition of CBDH, CBDM and Δ9-THCH closes the loop and might serve in the future for researchers to distinguish between these phytocannabinoids isomers that show a very similar analytical behaviour. Lastly, CBDH was assessed for biological tests in vivo showing interesting analgesic activity at low doses in mice.