RESUMO
Heart diseases, especially acute coronary syndrome (ACS), are among the most severe illnesses that often lead to death. Despite significant advances in the prevention and treatment of ACS, the incidence of the disease and its complications are very serious. The imbalance between pro- and antioxidant systems, the formation of active carbonyl compounds, and the end products of glycation in the blood and tissues are the key moments in the development of heart and neurological disorders leading to a change of behavioral responses. So, the search for antioxidants with cardio- and neuroprotective effects is an urgent task. This study was aimed at evaluating the effects of Corvitin and 2-oxoglutarate on physiological parameters, heart histology, and markers of carbonyl/oxidative stress of rats with pituitrin-isoproterenol-induced myocardial damage (PIMD). Increased sweating, tachycardia, significantly decreased locomotor and exploratory activity, changes of ECG, heart histology, and biochemical changes were observed in the PIMD-group. The administration of Corvitin or 2-OG led to the recovery of locomotor and cognitive activities of the rats, improvement in heart histology, a decrease in the levels of thiobarbituric acid reactive substances, advanced glycated end products, and various changes in the activity of the antioxidant enzymes, 6 days after PIMD. So, Corvitin and exogenous 2-OG show cardio- and neuroprotective effects through the decrease of carbonyl/oxidative stress and regulation of the activity of the antioxidant system.
RESUMO
INTRODUCTION: This article is part of the Focus Theme of METHODS of Information in Medicine on "Managing Interoperability and Complexity in Health Systems". BACKGROUND: Data heterogeneity is one of the critical problems in analysing, reusing, sharing or linking datasets. Metadata, whilst adding semantic description to data, adds an additional layer of complexity in the heterogeneity of metadata descriptors themselves. This can be managed by using a pre-defined model to extract the metadata, but this can reduce the richness of the data extracted. OBJECTIVES: to link the South London Stroke Register (SLSR), the London Air Pollution toolkit (LAP) and the Clinical Practice Research Datalink (CPRD) while transforming data into the Web Ontology Language (OWL) format. METHODS: We used a four-step transformation approach to prepare meta-descriptions, convert data, generate and update meta-classes and generate OWL files. We validated the correctness of the transformed OWL files by issuing queries and assessing results against the original source data. RESULTS: We have transformed SLSR LAP and CPRD into OWL format. The linked SLSR and CPRD OWL file contains 3644 male and 3551 female patients. The linked SLSR and LAP OWL file shows that there are 17 out of 35 outward postcode areas, where no overlapping data can support further analysis between SLSR and LAP. CONCLUSIONS: Our approach generated a resultant set of transformed OWL formatted files, which are in a query-able format to run individual queries, or can be easily converted into other more suitable formats for further analysis, and the transformation was faithful with no loss or anomalies. Our results have shown that the proposed method provides a promising general approach to address data heterogeneity.
Assuntos
Registros Eletrônicos de Saúde , Armazenamento e Recuperação da Informação , Atenção Primária à Saúde , Sistema de Registros , Integração de Sistemas , Terminologia como Assunto , Bases de Dados Factuais , Estudos de Viabilidade , Feminino , Humanos , Masculino , Vigilância de Produtos Comercializados , SemânticaRESUMO
Juxtaglomerular neurons represent one of the largest cellular populations in the mammalian olfactory bulb yet their role for signal processing remains unclear. We used two-photon imaging and electrophysiological recordings to clarify the in vivo properties of these cells and their functional organization in the juxtaglomerular space. Juxtaglomerular neurons coded for many perceptual characteristics of the olfactory stimulus such as (1) identity of the odorant, (2) odorant concentration, (3) odorant onset, and (4) offset. The odor-responsive neurons clustered within a narrow area surrounding the glomerulus with the same odorant specificity, with ~80% of responding cells located ≤20 µm from the glomerular border. This stereotypic spatial pattern of activated cells persisted at different odorant concentrations and was found for neurons both activated and inhibited by the odorant. Our data identify a principal glomerulus with a narrow shell of juxtaglomerular neurons as a basic odor coding unit in the glomerular layer and underline the important role of intraglomerular circuitry.
Assuntos
Rede Nervosa/citologia , Rede Nervosa/fisiologia , Odorantes , Bulbo Olfatório/citologia , Bulbo Olfatório/fisiologia , Neurônios Receptores Olfatórios/fisiologia , Animais , Feminino , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Neurônios/fisiologiaRESUMO
G-protein-coupled metabotropic glutamate group I receptors (mGluR1s) mediate synaptic transmission and plasticity in Purkinje cells and, therefore, critically determine cerebellar motor control and learning. Purkinje cells express two members of the G-protein G(q) family, namely G(q) and G11. Although in vitro coexpression of mGluR1 with either Galpha11 or Galpha(q) produces equally well functioning signaling cascades, Galpha(q)- and Galpha11-deficient mice exhibit distinct alterations in motor coordination. By using whole-cell recordings and Ca2+ imaging in Purkinje cells, we show that Galpha(q) is required for mGluR-dependent synaptic transmission and for long-term depression (LTD). Galpha11 has no detectable contribution for synaptic transmission but also contributes to LTD. Quantitative single-cell RT-PCR analyses in Purkinje cells demonstrate a more than 10-fold stronger expression of Galpha(q) versus Galpha11. Our findings suggest an expression level-dependent action of Galpha(q) and Galpha11 for Purkinje cell signaling and assign specific roles of these two G(q) isoforms for motor coordination.
Assuntos
Subunidades alfa Gq-G11 de Proteínas de Ligação ao GTP/fisiologia , Células de Purkinje/metabolismo , Animais , Comportamento Animal/fisiologia , Células COS , Cálcio/metabolismo , Sinalização do Cálcio/genética , Cerebelo/citologia , Cerebelo/metabolismo , Chlorocebus aethiops , Potenciais Pós-Sinápticos Excitadores/genética , Potenciais Pós-Sinápticos Excitadores/fisiologia , Corantes Fluorescentes , Subunidades alfa Gq-G11 de Proteínas de Ligação ao GTP/genética , Subunidades alfa Gq-G11 de Proteínas de Ligação ao GTP/metabolismo , Depressão Sináptica de Longo Prazo/genética , Depressão Sináptica de Longo Prazo/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Atividade Motora/genética , Atividade Motora/fisiologia , Plasticidade Neuronal/fisiologia , Técnicas de Patch-Clamp , Subunidades Proteicas/genética , Subunidades Proteicas/metabolismo , Subunidades Proteicas/fisiologia , Receptores de Glutamato Metabotrópico/metabolismo , Transdução de Sinais/fisiologia , Transmissão Sináptica/genética , Transmissão Sináptica/fisiologiaRESUMO
The zebrafish larva is a powerful model for the analysis of behaviour and the underlying neuronal network activity during early stages of development. Here we employ a new approach of "in vivo" Ca(2+) imaging in this preparation. We demonstrate that bolus injection of membrane-permeable Ca(2+) indicator dyes into the spinal cord of zebrafish larvae results in rapid staining of essentially the entire spinal cord. Using two-photon imaging, we could monitor Ca(2+) signals simultaneously from a large population of spinal neurons with single-cell resolution. To test the method, Ca(2+) transients were produced by iontophoretic application of glutamate and, as observed for the first time in a living preparation, of GABA or glycine. Glycine-evoked Ca(2+) transients were blocked by the application of strychnine. Sensory stimuli that trigger escape reflexes in mobile zebrafish evoked Ca(2+) transients in distinct neurons of the spinal network. Moreover, long-term recordings revealed spontaneous Ca(2+) transients in individual spinal neurons. Frequently, this activity occurred synchronously among many neurons in the network. In conclusion, the new approach permits a reliable analysis with single-cell resolution of the functional organisation of developing neuronal networks.
Assuntos
Cálcio/fisiologia , Diagnóstico por Imagem , Rede Nervosa/fisiologia , Peixe-Zebra/fisiologia , Animais , Cálcio/química , Sinalização do Cálcio/efeitos dos fármacos , Sinalização do Cálcio/fisiologia , Corantes , Aminoácidos Excitatórios/antagonistas & inibidores , Aminoácidos Excitatórios/farmacologia , Corantes Fluorescentes , Glicinérgicos/farmacologia , Técnicas In Vitro , Larva/fisiologia , Rede Nervosa/efeitos dos fármacos , Rede Nervosa/crescimento & desenvolvimento , Neurônios/fisiologia , Medula Espinal/citologia , Medula Espinal/crescimento & desenvolvimento , Medula Espinal/fisiologia , Estricnina/farmacologiaRESUMO
The pituitary adenylate cyclase activating polypeptide (PACAP) type I receptor (PAC1) is a G-protein-coupled receptor binding the strongly conserved neuropeptide PACAP with 1000-fold higher affinity than the related peptide vasoactive intestinal peptide. PAC1-mediated signaling has been implicated in neuronal differentiation and synaptic plasticity. To gain further insight into the biological significance of PAC1-mediated signaling in vivo, we generated two different mutant mouse strains, harboring either a complete or a forebrain-specific inactivation of PAC1. Mutants from both strains show a deficit in contextual fear conditioning, a hippocampus-dependent associative learning paradigm. In sharp contrast, amygdala-dependent cued fear conditioning remains intact. Interestingly, no deficits in other hippocampus-dependent tasks modeling declarative learning such as the Morris water maze or the social transmission of food preference are observed. At the cellular level, the deficit in hippocampus-dependent associative learning is accompanied by an impairment of mossy fiber long-term potentiation (LTP). Because the hippocampal expression of PAC1 is restricted to mossy fiber terminals, we conclude that presynaptic PAC1-mediated signaling at the mossy fiber synapse is involved in both LTP and hippocampus-dependent associative learning.
Assuntos
Aprendizagem por Associação/fisiologia , Potenciação de Longa Duração/fisiologia , Fibras Musgosas Hipocampais/metabolismo , Receptores do Hormônio Hipofisário/deficiência , Receptores do Hormônio Hipofisário/metabolismo , Animais , Aprendizagem da Esquiva/fisiologia , Sinais (Psicologia) , Eletrochoque , Técnicas In Vitro , Aprendizagem em Labirinto/fisiologia , Camundongos , Camundongos Knockout , Camundongos Mutantes , Plasticidade Neuronal/fisiologia , Técnicas de Patch-Clamp , Terminações Pré-Sinápticas/metabolismo , Prosencéfalo/metabolismo , Receptores de Polipeptídeo Hipofisário Ativador de Adenilato Ciclase , Receptores de Polipeptídeo Hipofisário Ativador de Adenilato Ciclase , Receptores do Hormônio Hipofisário/genética , Transdução de Sinais/fisiologia , Comportamento SocialRESUMO
We have used rapid confocal microscopy to investigate the mechanism of Ca(2+) signals in individual dendritic spines of hippocampal CA1 pyramidal cells. The experiments focused on the signals that occur during single weak synaptic responses that were subthreshold for triggering postsynaptic action potentials. These Ca(2+) signals were not strongly affected by blocking the EPSPs with the AMPA receptor antagonist CNQX. The signals were also not strongly reduced by blocking T-type voltage-gated Ca(2+) channels (VGCCs) with Ni(2+) or by blocking a broad range of VGCCs with intracellular D890. The spine Ca(2+) signals were blocked by NMDA receptor channel (NMDAR) antagonist and had the voltage dependence characteristic of these channels. Neither ryanodine nor cyclopiazonic acid (CPA), substances known to deplete intracellular Ca(2+) stores, substantially reduced the amplitude of synaptically evoked Ca(2+) signals. CPA slowed the recovery phase of Ca(2+) signals in spines produced by synaptic stimulation or by backpropagating action potentials, suggesting a role of intracellular stores in Ca(2+) reuptake. Thus, we find that Ca(2+) release from intracellular stores is not required to produce spine Ca(2+) signals. We conclude that synaptic Ca(2+) signals in spines are primarily caused by Ca(2+) entry through NMDARs. Although these channels are largely blocked by Mg(2+) at voltages near the resting potential, they can nevertheless produce significant Ca(2+) elevation. The resulting Ca(2+) signals are an integral component of individual evoked or spontaneous synaptic events and may be important in the maintenance of synaptic function.
Assuntos
Sinalização do Cálcio/fisiologia , Dendritos/fisiologia , Hipocampo/citologia , Receptores de N-Metil-D-Aspartato/fisiologia , 2-Amino-5-fosfonovalerato/farmacologia , 6-Ciano-7-nitroquinoxalina-2,3-diona/farmacologia , Animais , Cálcio/metabolismo , Canais de Cálcio Tipo T/fisiologia , Sinalização do Cálcio/efeitos dos fármacos , Células Cultivadas , Dendritos/química , Fosfatos de Dinucleosídeos/farmacologia , Inibidores Enzimáticos/farmacologia , Antagonistas de Aminoácidos Excitatórios/farmacologia , Potenciais Pós-Sinápticos Excitadores/efeitos dos fármacos , Potenciais Pós-Sinápticos Excitadores/fisiologia , Potenciais da Membrana/efeitos dos fármacos , Potenciais da Membrana/fisiologia , Microscopia Confocal , Células Piramidais/fisiologia , Células Piramidais/ultraestrutura , Ratos , Ratos Wistar , Receptores de AMPA/fisiologia , Rianodina/farmacologiaRESUMO
Dendritic spines are assumed to be the smallest units of neuronal integration. Because of their miniature size, however, many of their functional properties are still unclear. New insights in spine physiology have been provided by two-photon laser-scanning microscopy which allows fluorescence imaging with high spatial resolution and minimal photodamage. For example, two-photon imaging has been employed successfully for the measurement of activity-induced calcium transients in individual spines. Here, we describe the first application of two-photon imaging to measure Na+ transients in spines and dendrites of CA1 pyramidal neurons in hippocampal slices. Whole-cell patch-clamped neurons were loaded with the Na(+)-indicator dye SBFI (sodium-binding benzofuran-isophthalate). In situ calibration of SBFI fluorescence with ionophores enabled the determination of the actual magnitude of the [Na+]i changes. We found that back-propagating action potentials (APs) evoked Na+ transients throughout the proximal part of the dendritic tree and adjacent spines. The action-potential-induced [Na+]i transients reached values of 4 mM for a train of 20 APs and monotonically decayed with a time constant of several seconds. These results represent the first demonstration of activity-induced Na+ accumulation in spines. Our results demonstrate that two-photon Na+ imaging represents a powerful tool for extending our knowledge on Na+ signaling in fine cellular subcompartments.
Assuntos
Dendritos/ultraestrutura , Neurônios/ultraestrutura , Sódio/metabolismo , Potenciais de Ação/fisiologia , Animais , Benzofuranos , Calibragem , Dendritos/metabolismo , Dendritos/fisiologia , Éteres Cíclicos , Corantes Fluorescentes , Cinética , Camundongos , Microscopia Confocal , Neurônios/metabolismo , Neurônios/fisiologia , Fótons , Canais de Sódio/metabolismoRESUMO
Long-term potentiation (LTP) is a cellular mechanism that potentially underlies learning and memory. To test the hypothesis that LTP is involved in activity-dependent synapse formation, we combined whole-cell recordings and confocal microscopy to investigate hippocampal glutamatergic synapses at their earliest stages of development. Here we report that, during the first postnatal week, the hippocampal glutamatergic network becomes gradually functional owing to the transformation of precursor, pure NMDA (N-methyl-D-aspartate)-receptor-based synaptic contacts into conducting AMPA (alpha-amino-3-hydroxy-5-methylisoxazole-4-proprionate)/NMDA-re cep tor-type synapses. This functional synapse induction is caused by an associative form of LTP, so it is input-specific and easily triggered experimentally by pairing presynaptic stimulation with postsynaptic depolarization. Our results challenge previous views that LTP occurs in the hippocampus only at later stages of development and that its induction requires dendritic spines. They also provide direct evidence that LTP is important for the activity-dependent formation of conducting glutamatergic synapses in the developing mammalian brain.
Assuntos
Hipocampo/fisiologia , Potenciação de Longa Duração/fisiologia , Sinapses/fisiologia , Animais , Animais Recém-Nascidos , Potenciais Evocados , Hipocampo/crescimento & desenvolvimento , Técnicas In Vitro , N-Metilaspartato/fisiologia , Técnicas de Patch-Clamp , Células Piramidais/fisiologia , Ratos , Ratos Wistar , Receptores de N-Metil-D-Aspartato/fisiologiaRESUMO
Excitatory postsynaptic currents (EPSCs) at the parallel fiber and climbing fiber to Purkinje cell synapses were studied by whole-cell clamping Purkinje cells in cerebellar slices. Reducing glutamate release with adenosine or GABA decreased the amplitude of the EPSCs, with a larger suppression being produced at the parallel fiber synapse. Reducing glutamate release also speeded the decay of the EPSCs, and this effect was not a series resistance artefact since postsynaptic reduction of the current with CNQX did not speed the EPSC decay. Blocking glutamate uptake slowed the decay of the EPSCs. At the climbing fiber synapse, adenosine had little suppressive effect on the smaller EPSC evoked by the second of a pair of stimuli. Blocking desensitization of postsynaptic AMPA receptors prolonged the EPSC decay, preferentially increased the size of the second EPSC, and resulted in adenosine having a similar suppressive effect on the first and second EPSC. These data suggest that, at these synapses, the fall of glutamate concentration in the synaptic cleft overlaps with the decay of the EPSC, and that the EPSC size and duration are controlled by the amount of glutamate released, the rate of glutamate uptake, and desensitization.
Assuntos
Cerebelo/fisiologia , Terminações Pré-Sinápticas/fisiologia , Células de Purkinje/fisiologia , Sinapses/fisiologia , Adenosina/farmacologia , Animais , Condutividade Elétrica , Antagonistas de Aminoácidos Excitatórios , Fibras Nervosas/fisiologia , Neurotransmissores/metabolismo , Ratos , Receptores de AMPA/fisiologia , Sinapses/efeitos dos fármacos , Ácido gama-Aminobutírico/farmacologiaRESUMO
Arachidonic acid has been proposed as an intercellular messenger in the nervous system. It is released when glutamate acts on postsynaptic receptors, potentiates NMDA receptor currents and depresses glutamate uptake. Here we report the effects of arachidonic acid on non-NMDA receptor currents, studied by whole-cell clamping isolated neurons and neurons in tissue slices. In cultured cerebellar granule cells and in freshly isolated hippocampal pyramidal cells arachidonic acid decreased the current produced by iontophoresed AMPA. This depression was not due to increased desensitization of the AMPA receptor. In cerebellar slices, arachidonic acid depressed the non-NMDA component of the synaptic current at the mossy fibre to granule cell and the parallel fibre to Purkinje cell synapses. However, this depression was not always seen, possibly because the lipophilic arachidonic acid is absorbed by superficial cells in the slice and does not reach the synapse being studied. Depression of non-NMDA receptor currents by arachidonic acid may reflect the presence of an arachidonic acid binding site on the non-NMDA receptor, but non-NMDA receptor subunits show much less sequence homology with fatty acid binding proteins than does the NMDA receptor.
Assuntos
Ácido Araquidônico/farmacologia , Cerebelo/fisiologia , Ácido Caínico/farmacologia , Proteínas de Neoplasias , Proteínas do Tecido Nervoso , Neurônios/fisiologia , Células de Purkinje/fisiologia , Receptores de AMPA/fisiologia , Receptores de Glutamato/fisiologia , Receptores de Ácido Caínico/fisiologia , Ácido alfa-Amino-3-hidroxi-5-metil-4-isoxazol Propiônico/farmacologia , Sequência de Aminoácidos , Animais , Proteínas de Transporte/química , Células Cultivadas , Relação Dose-Resposta a Droga , Proteína 7 de Ligação a Ácidos Graxos , Proteínas de Ligação a Ácido Graxo , Ácidos Graxos/metabolismo , Técnicas In Vitro , Dados de Sequência Molecular , Neurônios/efeitos dos fármacos , Células de Purkinje/efeitos dos fármacos , Ratos , Receptores de AMPA/antagonistas & inibidores , Receptores de Glutamato/química , Receptores de Ácido Caínico/antagonistas & inibidores , Homologia de Sequência de Aminoácidos , Sinapses/efeitos dos fármacos , Sinapses/fisiologia , Transmissão Sináptica/efeitos dos fármacosRESUMO
Long-term potentiation is currently a leading candidate for a physiological memory mechanism in CNS. The interpretation of this phenomenon is contradictory in many respects. However, there is clear evidence that long-term potentiation is critically dependent on activation of N-methyl-D-aspartate receptors. Recently it has been shown that extracellularly applied glutamate also induces long-lasting changes in the properties of synaptic transmission in the hippocampus that can be attributed to long-term potentiation. The involvement of presynaptic mechanisms has been reported. Here we demonstrate a definite increase in both the open time and open-state probability of N-methyl-D-aspartate-operated channels, induced by prolonged application of glutamate to hippocampal slices.
Assuntos
Glutamatos/farmacologia , Hipocampo/metabolismo , Canais Iônicos/metabolismo , N-Metilaspartato/metabolismo , Neurônios/metabolismo , Animais , Ácido Glutâmico , Hipocampo/citologia , Hipocampo/efeitos dos fármacos , Técnicas In Vitro , Canais Iônicos/efeitos dos fármacos , Potenciais da Membrana/efeitos dos fármacos , Plasticidade Neuronal/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Ratos , Ratos Wistar , Receptores de N-Metil-D-Aspartato/efeitos dos fármacos , Receptores de N-Metil-D-Aspartato/metabolismo , Sinapses/efeitos dos fármacos , Sinapses/metabolismoRESUMO
Using in situ whole-cell patch clamp of hippocampal CA1 pyramidal neurons we demonstrate that glutamate initiates processes resulting in an increase in the amplitude of the excitatory post-synaptic current (EPSC). In adult animals both, NMDA and non-NMDA components of the EPSC increase in parallel. In young animals only the NMDA component is increased. A similar enhancement of the EPSC can be achieved by the stimulation of excitatory synaptic inputs to CA1 neurons with the frequency of the theta-rhythm. EPSCs remain enhanced for more than 60 min. The selective enhancement of the NMDA component in young animals is inhibited by preincubation of slices with the NO-synthase blocker, N omega-nitro-L-arginine (NA) or by the NO-scavenger, hemoglobin.
Assuntos
Glutamatos/farmacologia , N-Metilaspartato/fisiologia , Neurônios/fisiologia , Sinapses/fisiologia , Ritmo Teta/efeitos dos fármacos , Envelhecimento/fisiologia , Animais , Arginina/análogos & derivados , Arginina/farmacologia , Potenciais Evocados/fisiologia , Ácido Glutâmico , Hemoglobinas/farmacologia , Técnicas In Vitro , Plasticidade Neuronal/fisiologia , Neurônios/efeitos dos fármacos , Nitroarginina , Norepinefrina/farmacologia , Ratos , Ratos Wistar , Transmissão Sináptica/efeitos dos fármacos , Transmissão Sináptica/fisiologiaRESUMO
The selective agonist of metabotropic glutamate receptors, t-ACPD (trans-1-aminocyclopentyl-1,3-dicarboxylic acid) (100-250 microM), reversibly inhibited extracellularly recorded EPSP (excitatory postsynaptic potentials) in the CA1 layer of rat hippocampus. This effect was accompanied by depression of electrical excitability of CA1 neurons as revealed by their antidromic stimulation. The excitability of CA3 neurons remained uneffected. Peculiarly, excitatory postsynaptic currents recorded in voltage clamped, internally perfused CA1 cells remained unaltered. Selective depolarization of CA1 neurons may account for the phenomena described.
Assuntos
Cicloleucina/análogos & derivados , Hipocampo/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Transmissão Sináptica/efeitos dos fármacos , Animais , Cicloleucina/farmacologia , Potenciais Evocados/efeitos dos fármacos , Técnicas In Vitro , RatosRESUMO
Whole-cell patch-clamp was used to investigate synaptic transmission in hippocampal slices. Excitatory post-synaptic currents (EPSCs) were facilitated by low (less than or equal to 1 microM) adenosine (Ado) concentrations, while high concentrations had well-known inhibitory effects on the EPSC. When added on the background of preapplied Ado, methylxanthines caused a large potentiation of EPSCs. At saturation, the enhanced EPSC could exceed the control almost by an order of magnitude. Pertussis toxin strongly impaired the ability of Ado to block EPSCs but did not augment the facilitatory effect. The two components of the EPSC mediated by N-methyl-D-aspartate (NMDA) and non-NMDA receptors were facilitated simultaneously and in equal proportions.