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1.
PLoS One ; 19(8): e0304521, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39159188

RESUMO

Zanthoxylum rhetsa (ZR) is used traditionally to manage a variety of ailments, including diabetes. Oxidative stress may accelerate the diabetic condition. The available antidiabetic and antioxidant drugs have many shortcomings including resistance, inefficiency, higher dose, side effects and costs. The goal of the current investigation was to assess the antioxidant capacity and antidiabetic activity of an ethanolic extract of Zanthoxylum rhetsa root bark (ZRRB) through in vitro, in vivo, and in silico methods. The antioxidant capacity of the ZRRB extract was measured using both the DPPH radical assay and the total antioxidant activity test. The oral glucose tolerance test (OGTT) and alloxan-induced diabetic mice model were also used to examine in vivo antidiabetic efficacy. Phytochemicals identification was done by GCMS analysis. Additionally, computational methods such as molecular docking, ADMET analysis, and molecular dynamics (MD) modeling were performed to determine the above pharmacological effects. The extract demonstrated significant DPPH scavenging activity (IC50 = 42.65 µg/mL). In the OGTT test and alloxan-induced diabetes mice model, the extract effectively lowered blood glucose levels. Furthermore, in vitro inhibition of pancreatic α-amylase studies demonstrated the ZRRB extract as a good antidiabetic crude drug (IC50 = 81.45 µg/mL). GCMS investigation confirmed that the crude extract contains 16 major phytoconstituents, which were docked with human peroxiredoxin-5, α-amylase, and sulfonylurea receptor 1. Docking and pharmacokinetic studies demonstrated that among 16 phytoconstituents, 6H-indolo[3,2,1-de] [1,5]naphthyridin-6-one (CID: 97176) showed the highest binding affinity to targeted enzymes, and imitated Lipinski's rule of five. Furthermore, MD simulation data confirmed that the aforementioned compound is very steady to the binding site of α-amylase and sulfonylurea receptor 1 receptors. Findings from in vitro, in vivo and in silico investigation suggest that ZRRB extract contains a lead compound that could be a potent source of antidiabetic drug candidate.


Assuntos
Antioxidantes , Diabetes Mellitus Experimental , Hipoglicemiantes , Simulação de Acoplamento Molecular , Casca de Planta , Extratos Vegetais , Zanthoxylum , Zanthoxylum/química , Animais , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Hipoglicemiantes/farmacologia , Hipoglicemiantes/química , Hipoglicemiantes/uso terapêutico , Camundongos , Diabetes Mellitus Experimental/tratamento farmacológico , Antioxidantes/farmacologia , Antioxidantes/química , Casca de Planta/química , Masculino , Raízes de Plantas/química , Cromatografia Gasosa-Espectrometria de Massas , Teste de Tolerância a Glucose , Etanol/química , Simulação de Dinâmica Molecular
2.
Mol Neurobiol ; 2024 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-38967904

RESUMO

Gut microbiota and infectious diseases affect neurological disorders, brain development, and function. Compounds generated in the gastrointestinal system by gut microbiota and infectious pathogens may mediate gut-brain interactions, which may circulate throughout the body and spread to numerous organs, including the brain. Studies shown that gut bacteria and disease-causing organisms may pass molecular signals to the brain, affecting neurological function, neurodevelopment, and neurodegenerative diseases. This article discusses microorganism-producing metabolites with neuromodulator activity, signaling routes from microbial flora to the brain, and the potential direct effects of gut bacteria and infectious pathogens on brain cells. The review also considered the neurological aspects of infectious diseases. The infectious diseases affecting neurological functions and the disease modifications have been discussed thoroughly. Recent discoveries and unique insights in this perspective need further validation. Research on the complex molecular interactions between gut bacteria, infectious pathogens, and the CNS provides valuable insights into the pathogenesis of neurodegenerative, behavioral, and psychiatric illnesses. This study may provide insights into advanced drug discovery processes for neurological disorders by considering the influence of microbial communities inside the human body.

4.
Heliyon ; 9(1): e12737, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36685474

RESUMO

Obesity is a severe public health burden and a major component of metabolic syndrome. It is critical to identify treatment medicines for obesity and associated inflammation. We examined the anti-obesity and anti-inflammatory properties of Musa acuminate seeds methanol extract in high-fat diet-induced obesity. Changes in body weight, Lee index, fat mass accumulation, serum cholesterol, and serum triglyceride were monitored. Alteration in the expression of PPARγ, GLUT4, and MCP-1 at the transcript level in adipose tissue was also studied. After tabulation of our data, a significant reduction (p < 0.05) was recorded for body weight gain, and fat mass accumulation followed by significant changes (p < 0.05) in serum cholesterol, and serum triglyceride levels by the extract. In agreement with the biochemical data, the extract was capable enough (p < 0.05) to reduce the mRNA expression of PPARγ, and MCP-1, confirming the ability of the extract to ameliorate the risk of obesity and obesity-associated inflammation. Moreover, an in-silico study showed the high binding affinity of the reported compounds from M. acuminate like Delphinidin, Umbelliferon with COX-2, PPARγ, and MCP-1, supporting the notion of the risk-reducing potential of M.acuminate for obesity and obesity mediated inflammatory.

5.
Molecules ; 27(20)2022 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-36296527

RESUMO

The Omicron variant (B.529) of COVID-19 caused disease outbreaks worldwide because of its contagious and diverse mutations. To reduce these outbreaks, therapeutic drugs and adjuvant vaccines have been applied for the treatment of the disease. However, these drugs have not shown high efficacy in reducing COVID-19 severity, and even antiviral drugs have not shown to be effective. Researchers thus continue to search for an effective adjuvant therapy with a combination of drugs or vaccines to treat COVID-19 disease. We were motivated to consider melatonin as a defensive agent against SARS-CoV-2 because of its various unique properties. Over 200 scientific publications have shown the significant effects of melatonin in treating diseases, with strong antioxidant, anti-inflammatory, and immunomodulatory effects. Melatonin has a high safety profile, but it needs further clinical trials and experiments for use as a therapeutic agent against the Omicron variant of COVID-19. It might immediately be able to prevent the development of severe symptoms caused by the coronavirus and can reduce the severity of the infection by improving immunity.


Assuntos
Tratamento Farmacológico da COVID-19 , Melatonina , Humanos , SARS-CoV-2 , Melatonina/farmacologia , Melatonina/uso terapêutico , Antioxidantes , Antivirais/farmacologia , Antivirais/uso terapêutico
6.
Prostaglandins Other Lipid Mediat ; 162: 106664, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35843503

RESUMO

The prevalence of obesity is increasing at an alarming rate and keeps on being one of the significant challenges of this century. Obesity promotes adipose tissue hypertrophy and causes the release of different pro-inflammatory cytokines, playing a significant role in the pathophysiology of metabolic syndrome. Aspirin is known as a potent anti-inflammatory drug, but its role in adipogenesis, adipocyte-specific inflammation, and metabolic syndrome is not well characterized. Thus, in this experiment, we aimed to determine the effect of low-dose aspirin on obesity, obesity-induced inflammation, and metabolic syndrome. High-fat diet-induced obese female mice (Swiss Albino) were used in our study. Mice were fed on a normal diet, a high-fat diet, and a low dose of aspirin (LDA) in the presence of a high-fat diet for 11 weeks. Body weight, lipid profile, adipose tissue size, and inflammatory status were analyzed after that period. The ∆∆CT method was used to calculate the relative mRNA expression of target genes. Treatment with a low dose of aspirin resulted in a significant reduction of body weight, visceral fat mass and serum total cholesterols, serum and adipose tissue triglycerides, and blood glucose levels in high-fat diet-induced obese mice compared to the untreated obese group. Consistent with these biochemical results, a significant reduction in mRNA expression of different genes like PPARγ, GLUT4, IL-6, TNFα, MCP-1, ICAM-I, and VCAM-I associated with adipogenesis and inflammation were noticed. Overall, current study findings indicate that low-dose aspirin reduces obesity, hyperlipidemia, adipocyte-specific inflammation, and metabolic syndrome in high-fat diet-induced obese mice.


Assuntos
Dieta Hiperlipídica , Síndrome Metabólica , Tecido Adiposo/metabolismo , Animais , Anti-Inflamatórios/farmacologia , Aspirina/farmacologia , Aspirina/uso terapêutico , Glicemia/metabolismo , Peso Corporal , Feminino , Inflamação/metabolismo , Interleucina-6/metabolismo , Síndrome Metabólica/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Obesos , Obesidade/metabolismo , PPAR gama/metabolismo , RNA Mensageiro/metabolismo , Triglicerídeos/metabolismo , Fator de Necrose Tumoral alfa/metabolismo
7.
Biochem Biophys Res Commun ; 608: 90-95, 2022 06 11.
Artigo em Inglês | MEDLINE | ID: mdl-35397428

RESUMO

Obesity is associated with low-grade chronic inflammation and has a remarkable role in the pathophysiology of metabolic complications. In triggering these inflammatory responses, the arachidonic acid (AA) cascade plays a key role. However, there is a lack of data on how supplementary AA would affect obesity, adipose tissue inflammation, and the AA cascade in obesity. This study aims to investigate how AA supplementation affects obesity, adipocyte morphology, inflammation, and AA cascade signaling. Male Swiss Albino mice were used in our experiment. The mice were fed high-fat diets to induce obesity, and these obese mice were treated with two different doses of AA for 3 weeks. A normal diet non-obese group and an untreated obese group were kept as controls. Bodyweight and daily food intake data were recorded during that period. After the treatment period, blood serum and white adipose tissue of the experimental mice were collected for colorimetric lipid profile tests, histology, and mRNA extraction. The ΔΔCT method was employed for calculating the relative mRNA expression of target genes. The findings of our study suggest that AA has no significant effects on body weight, visceral adiposity, adipose tissue morphology, and serum lipid profile. However, AA treatment has resulted in a significant down-regulation of pro-inflammatory markers as well as the COX pathway. Besides, up-regulation of 12/15-LOX has been observed, indicating the metabolism pathway of supplementary AA through the LOX pathway. Our findings indicate that AA treatment may not provide significant benefits in terms of body weight, visceral fat mass, or serum lipid profile. However, it has effectively alleviated obesity-induced adipocyte inflammation in high-fat diet-induced obese mice.


Assuntos
Adiposidade , Dieta Hiperlipídica , Adipócitos/metabolismo , Animais , Ácido Araquidônico/metabolismo , Peso Corporal , Dieta Hiperlipídica/efeitos adversos , Suplementos Nutricionais , Inflamação/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Obesos , Obesidade/tratamento farmacológico , Obesidade/etiologia , Obesidade/metabolismo , RNA Mensageiro/metabolismo
8.
Oxid Med Cell Longev ; 2021: 9974890, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34336128

RESUMO

The biological and therapeutic properties of seaweeds have already been well known. Several studies showed that among the various natural marine sources of antioxidants, seaweeds have become a potential source of antioxidants because of their bioactive compounds. Most of the metabolic diseases are caused by oxidative stress. It is very well known that antioxidants have a pivotal role in the treatment of those diseases. Recent researches have revealed the potential activity of seaweeds as complementary medicine, which have therapeutic properties for health and disease management. Among the seaweeds, brown seaweeds (Phaeophyta) and their derived bioactive substances showed excellent antioxidant properties than other seaweeds. This review focuses on brown seaweeds and their derived major bioactive compounds such as sulfated polysaccharide, polyphenol, carotenoid, and sterol antioxidant effects and molecular mechanisms in the case of the oxidative stress-originated disease. Antioxidants have a potential role in the modification of stress-induced signaling pathways along with the activation of the oxidative defensive pathways. This review would help to provide the basis for further studies to researchers on the potential antioxidant role in the field of medical health care and future drug development.


Assuntos
Antioxidantes/uso terapêutico , Estresse Oxidativo/efeitos dos fármacos , Alga Marinha/química , Antioxidantes/farmacologia , Humanos
9.
BMC Complement Med Ther ; 21(1): 82, 2021 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-33658026

RESUMO

BACKGROUND: Atopic dermatitis (AD) is a chronic allergic inflammatory skin disease characterized by complex pathogenesis including skin barrier dysfunction, immune-redox disturbances, and pruritus. Prolonged topical treatment with medications such as corticosteroids, calcineurin inhibitors, and T-cell inhibitors may have some potential side-effects. To this end, many researchers have explored numerous alternative therapies using natural products and mineral compounds with antioxidant or immunomodulatory effects to minimize toxicity and adverse-effects. In the current study, we investigated the effects of mineral complex material (MCM) treatment on 2, 4-dinitrochlorobenzene (DNCB)-induced AD-like skin lesions in SKH-1 hairless mice. METHODS: Animals were divided into four groups; normal control (NC), negative control treated with DNCB only (DNCB only), positive control treated with DNCB and tacrolimus ointment (PC) and experimental group treated with DNCB and MCM patch (MCM). Skin inflammation and lesion severity were investigated through analyses of skin parameters (barrier score and strength, moisture and trans-epidermal water loss level), histopathology, immunoglobulin E, and cytokines. In addition, reactive oxygen species (ROS), nitric oxide (NO), glutathione peroxidase (GPx), and catalase (CAT) levels were measured in both serum and skin lysate. RESULTS: Our results demonstrates that MCM patch improved the progression of AD-like skin lesions by significantly increasing skin barrier strength and decreasing trans-epidermal water loss. Additionally, dermal administration of MCM patch significantly reduced epidermal thickness, ROS, and NO levels in skin lysate. Furthermore, we found that MCM suppressed the levels of AD-involved (Th1 and Th2) cytokines such as IL-2, IFN-γ, and IL-4 in blood. In addition, the levels of other Th1, and Th2 and inflammatory cytokines such as IL-1ß, TNF-α, IL-6, IL-12(p70) and IL-10 were found lowest in the MCM group than in the DNCB only and PC groups. Moreover, we found total serum IgE level significantly increased after DNCB treatment, but decreased in the PC and MCM groups. CONCLUSION: Taken together, our findings suggest that MCM application may have beneficial effects either systemic or regional on DNCB-induced AD lesional skin via regulation of the skin barrier function and immune-redox response.


Assuntos
Dermatite Atópica/tratamento farmacológico , Minerais/administração & dosagem , Animais , Citocinas/metabolismo , Dermatite Atópica/induzido quimicamente , Dermatite Atópica/metabolismo , Dermatite Atópica/patologia , Dinitroclorobenzeno/efeitos adversos , Modelos Animais de Doenças , Feminino , Humanos , Imunoglobulina E/metabolismo , Camundongos , Camundongos Pelados , Óxido Nítrico/metabolismo , Pele/efeitos dos fármacos , Pele/patologia
10.
Med Hypotheses ; 121: 6-9, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30396494

RESUMO

Since the discovery of molecular hydrogen (H2) as a selective scavenger of free radicals like reactive oxygen species (ROS) and reactive nitrogen species (RNS), numerous studies have proved the potential application of H2 in therapeutic and preventative medicine. Moreover, H2 can regulate the intracellular signal as a signal modulator. However, it is still unclear in cell signaling involved in testosterone hormone production. Male fertility depends on the intra-testicular testosterone concentration, which is produced by the Leydig cell in the seminiferous tubules in testes. Although moderate amounts of ROS are needed for normal sperm function, the higher amounts might decrease testosterone production. High ROS decreases testosterone hormone production by dysregulation of hormonal signal from the hypothalamus to the Leydig cell as a result of redox imbalance. Lower level of testosterone fails to support the Leydig cell for the progression of spermatogenesis. Superoxide anion (O2-), hydroxyl radical (OH) and peroxynitrite (ONOO-) could also attack the DNA, lipid and protein, disrupting sperm structure and function and aggravating the milieu of male fertility and spermatogenesis. H2 regulates intracellular MAPK downstream cAMP signal and Ca2+ signal as a signal modulator to antagonize ROS signaling. Thus H2 can play a role in modulating signals involved in testosterone hormone production to improve male fertility caused by redox imbalance. We therefore hypothesize that molecular hydrogen may enhance testosterone production via cellular redox balance. By this hypothesis, we anticipate that molecular hydrogen may be an effective remedy in male infertility.


Assuntos
Hidrogênio/química , Infertilidade Masculina/metabolismo , Oxirredução , Espermatogênese/fisiologia , Testosterona/metabolismo , Fertilidade , Humanos , Células Intersticiais do Testículo/fisiologia , Masculino , Espécies Reativas de Nitrogênio/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais , Espermatozoides/metabolismo , Testículo/fisiologia
11.
BMC Complement Altern Med ; 17(1): 481, 2017 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-29029618

RESUMO

BACKGROUND: Atopic dermatitis (AD) is a chronic relapsing allergic inflammatory skin disease that currently affects millions of children and adults worldwide. Drugs used to treat these inflammatory diseases include anti-histamines, corticosteroids and calcineurin inhibitors but these drugs have their limitations such as adverse effects with their long-term usage. Thus, researcher's interest in several alternative and complementary therapies are continually growing and balneotherapy is one of these approaches. Therefore, we investigate the bathing effect of high concentration mineral spring water (HMW) on redox balance and immune modulation in 2,4-dinitrochlorobenzene (DNCB)-induced atopic dermatitis like inflammation in hairless mice. METHODS: We induced AD-like inflammation by application of DNCB on the dorsal skin of female skh-1 hairless mice. The mice were treated with 100% pure HMW (PHMW) and 10% diluted HMW (DHMW) through bathing once a day for 4 weeks. Tacrolimus ointment (0.1%) was used as positive control (PC) and only DNCB treatment as negative control (NeC) group. The severity of skin lesion inflammation was assessed through clinical scoring and observing scratching behavior. Levels of immunoglobulin E (IgE) and inflammatory cytokines in serum were detected by ELISA and multiplex bead array system, and the levels of oxidative stress-related biomarkers and antioxidant enzyme were also measured. RESULTS: We found that HMW significantly decreased the scratching behavior in PHMW and DHMW groups at the 2nd week and in PHMW group at 4th week compared to NeC group. Likewise, serum IgE level was significantly decreased in DHMW group as compared to NeC group. In line, the level of inflammatory cytokines in serum such as interleukin (IL)-1ß, IL-13 and tumor necrosis factor-α were significantly inhibited in PHMW and DHMW groups compared to NeC group. In parallel, total reactive oxygen species (ROS) of serum level was significantly decreased in PHMW treatment groups compared to NeC group. Consistently, serum malondialdehyde (MDA) level in PHMW group was lower than in NeC group. By contrast, glutathione peroxidase (GPx) activity was significantly enhanced in PHMW than NeC. CONCLUSION: Collectively, our study indicates a balneotherapeutic effect of HMW on DNCB-induced AD like inflammation in hairless mice via immunomodulation and redox balance.


Assuntos
Balneologia , Dermatite Atópica/terapia , Águas Minerais/uso terapêutico , Animais , Dermatite Atópica/induzido quimicamente , Dermatite Atópica/patologia , Dinitroclorobenzeno/efeitos adversos , Modelos Animais de Doenças , Feminino , Imunomodulação , Camundongos , Camundongos Pelados , Oxirredução , Pele/patologia
12.
Nat Commun ; 7: 12102, 2016 07 06.
Artigo em Inglês | MEDLINE | ID: mdl-27381274

RESUMO

Brain development and interictal function are unaffected in many paroxysmal neurological channelopathies, possibly explained by homoeostatic plasticity of synaptic transmission. Episodic ataxia type 1 is caused by missense mutations of the potassium channel Kv1.1, which is abundantly expressed in the terminals of cerebellar basket cells. Presynaptic action potentials of small inhibitory terminals have not been characterized, and it is not known whether developmental plasticity compensates for the effects of Kv1.1 dysfunction. Here we use visually targeted patch-clamp recordings from basket cell terminals of mice harbouring an ataxia-associated mutation and their wild-type littermates. Presynaptic spikes are followed by a pronounced afterdepolarization, and are broadened by pharmacological blockade of Kv1.1 or by a dominant ataxia-associated mutation. Somatic recordings fail to detect such changes. Spike broadening leads to increased Ca(2+) influx and GABA release, and decreased spontaneous Purkinje cell firing. We find no evidence for developmental compensation for inherited Kv1.1 dysfunction.


Assuntos
Potenciais de Ação/efeitos dos fármacos , Ataxia/fisiopatologia , Canalopatias/fisiopatologia , Canal de Potássio Kv1.1/metabolismo , Mioquimia/fisiopatologia , Células de Purkinje/metabolismo , Animais , Ataxia/genética , Ataxia/metabolismo , Cálcio/metabolismo , Canalopatias/genética , Canalopatias/metabolismo , Modelos Animais de Doenças , Venenos Elapídicos/farmacologia , Feminino , Expressão Gênica , Canal de Potássio Kv1.1/antagonistas & inibidores , Canal de Potássio Kv1.1/genética , Camundongos , Camundongos Transgênicos , Microtomia , Mutação , Mioquimia/genética , Mioquimia/metabolismo , Técnicas de Patch-Clamp , Terminações Pré-Sinápticas/efeitos dos fármacos , Terminações Pré-Sinápticas/metabolismo , Terminações Pré-Sinápticas/patologia , Células de Purkinje/efeitos dos fármacos , Células de Purkinje/patologia , Transmissão Sináptica/efeitos dos fármacos , Técnicas de Cultura de Tecidos , Ácido gama-Aminobutírico/metabolismo
13.
Epilepsy Behav ; 61: 185-191, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-27371883

RESUMO

BACKGROUND: Against a backdrop of recommendations for increasing access to and uptake of early surgical intervention for children with medically intractable epilepsy, it is important to understand how parents and professionals decide to put children forward for epilepsy surgery and what their decisional support needs are. AIM: The aim of this study was to explore how parents and health professionals make decisions regarding putting children forward for pediatric epilepsy surgery. METHODS: Individual interviews were conducted with nine parents of children who had undergone pediatric epilepsy surgery at a specialist children's hospital and ten healthcare professionals who made up the children's epilepsy surgery service multidisciplinary healthcare team (MDT). Three MDT meetings were also observed. Data were analyzed thematically. FINDINGS: Four themes were generated from analysis of interviews with parents: presentation of surgery as a treatment option, decision-making, looking back, and interventions. Three themes were generated from analysis of interviews/observations with health professionals: triangulating information, team working, and patient and family perspectives. DISCUSSION: Parents wanted more information and support in deciding to put their child forward for epilepsy surgery. They attempted to balance the potential benefits of surgery against any risks of harm. For health professionals, a multidisciplinary approach was seen as crucial to the decision-making process. Advocating for the family was perceived to be the responsibility of nonmedical professionals. CONCLUSION: Decision-making can be supported by incorporating families into discussions regarding epilepsy surgery as a potential treatment option earlier in the process and by providing families with additional information and access to other parents with similar experiences.


Assuntos
Tomada de Decisão Clínica , Epilepsia/cirurgia , Pessoal de Saúde , Pais , Adolescente , Adulto , Fatores Etários , Idade de Início , Criança , Pré-Escolar , Etnicidade , Família , Feminino , Humanos , Lactente , Masculino , Equipe de Assistência ao Paciente , Medição de Risco , Inquéritos e Questionários , Resultado do Tratamento , Reino Unido
14.
J Biol Chem ; 284(13): 8726-37, 2009 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-19141616

RESUMO

gamma-Aminobutyric acid type A (GABA(A)) receptors, a family of Cl(-)-permeable ion channels, mediate fast synaptic inhibition as postsynaptically enriched receptors for gamma-aminobutyric acid at GABAergic synapses. Here we describe an alternative type of inhibition mediated by GABA(A) receptors present on neocortical glutamatergic nerve terminals and examine the underlying signaling mechanism(s). By monitoring the activity of the presynaptic CaM kinase II/synapsin I signaling pathway in isolated nerve terminals, we demonstrate that GABA(A) receptor activation correlated with an increase in basal intraterminal [Ca(2+)](i). Interestingly, this activation of GABA(A) receptors resulted in a reduction of subsequent depolarization-evoked Ca(2+) influx, which thereby led to an inhibition of glutamate release. To investigate how the observed GABA(A) receptor-mediated modulation operates, we determined the sensitivity of this process to the Na-K-2Cl cotransporter 1 antagonist bumetanide, as well as substitution of Ca(2+) with Ba(2+), or Ca(2+)/calmodulin inhibition by W7. All of these treatments abolished the modulation by GABA(A) receptors. Application of selective antagonists of voltage-gated Ca(2+) channels (VGCCs) revealed that the GABA(A) receptor-mediated modulation of glutamate release required the specific activity of L- and R-type VGCCs. Crucially, the inhibition of release by these receptors was abolished in terminals isolated from R-type VGCC knock-out mice. Together, our results indicate that a functional coupling between nerve terminal GABA(A) receptors and L- or R-type VGCCs is mediated by Ca(2+)/calmodulin-dependent signaling. This mechanism provides a GABA-mediated control of glutamatergic synaptic activity by a direct inhibition of glutamate release.


Assuntos
Canais de Cálcio/metabolismo , Sinalização do Cálcio/fisiologia , Cálcio/metabolismo , Calmodulina/metabolismo , Ácido Glutâmico/metabolismo , Receptores de GABA-A/metabolismo , Sinaptossomos/metabolismo , Animais , Bário/farmacologia , Bumetanida/farmacologia , Sinalização do Cálcio/efeitos dos fármacos , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Masculino , Camundongos , Camundongos Knockout , Ratos , Ratos Sprague-Dawley , Inibidores de Simportadores de Cloreto de Sódio e Potássio , Sinapsinas/metabolismo
15.
Neuron ; 57(6): 917-29, 2008 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-18367092

RESUMO

In the cerebral cortex, GABAergic interneurons are often regarded as fast-spiking cells. We have identified a type of slow-spiking interneuron that offers distinct contributions to network activity. "Ivy" cells, named after their dense and fine axons innervating mostly basal and oblique pyramidal cell dendrites, are more numerous than the parvalbumin-expressing basket, bistratified, or axo-axonic cells. Ivy cells express nitric oxide synthase, neuropeptide Y, and high levels of GABA(A) receptor alpha1 subunit; they discharge at a low frequency with wide spikes in vivo, yet are distinctively phase-locked to behaviorally relevant network rhythms including theta, gamma, and ripple oscillations. Paired recordings in vitro showed that Ivy cells receive depressing EPSPs from pyramidal cells, which in turn receive slowly rising and decaying inhibitory input from Ivy cells. In contrast to fast-spiking interneurons operating with millisecond precision, the highly abundant Ivy cells express presynaptically acting neuromodulators and regulate the excitability of pyramidal cell dendrites through slowly rising and decaying GABAergic inputs.


Assuntos
Córtex Cerebral/citologia , Rede Nervosa/fisiologia , Neurônios/fisiologia , Óxido Nítrico/metabolismo , Transmissão Sináptica/fisiologia , Ácido gama-Aminobutírico/metabolismo , Potenciais de Ação/fisiologia , Potenciais de Ação/efeitos da radiação , Animais , Animais Recém-Nascidos , Comportamento Animal , Biotina/análogos & derivados , Biotina/metabolismo , Estimulação Elétrica/métodos , Hipocampo/citologia , Masculino , Microscopia Imunoeletrônica/métodos , Proteínas do Tecido Nervoso/metabolismo , Neurônios/classificação , Neurônios/ultraestrutura , Parvalbuminas/metabolismo , Técnicas de Patch-Clamp/métodos , Ratos , Ratos Sprague-Dawley , Receptores de GABA-A/metabolismo , Transmissão Sináptica/efeitos da radiação
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