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1.
ESMO Open ; 7(5): 100550, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35994790

RESUMO

BACKGROUND: Anxiety and depression in patients with cancer is associated with decreased quality of life and increased morbidity and mortality. However, these are often overlooked and untreated. Early-phase clinical trials (EPCTs) recruit patients with advanced cancers who frequently lack future treatment options, which may lead to increased anxiety and depression. Despite this, EPCTs do not routinely consider psychological screening for patients. PATIENTS AND METHODS: This prospective observational study explored levels of anxiety and depression alongside impact of trial participation in the context of EPCTs. The Hospital Anxiety and Depression Scale and the Brief Illness Perceptions Questionnaire were completed at the point of EPCT consent, the end of screening and at pre-specified time points thereafter. RESULTS: Sixty-four patients (median age 56 years; median Eastern Cooperative Oncology Group performance status 1) were recruited. At consent, 57 patients returned questionnaires; 39% reported clinically relevant levels of anxiety whilst 18% reported clinically relevant levels of depression. Sixty-three percent of patients experiencing psychological distress had never previously reported this. Males were more likely to be depressed (P = 0.037) and females were more likely to be anxious (P = 0.011). Changes in anxiety or depression were observed after trial enrolment on an individual level, but not significant on a population level. CONCLUSIONS: Patients on EPCTs are at an increased risk of anxiety and depression but may not seek relevant support. Sites offering EPCTs should consider including psychological screening to encourage a more holistic approach to cancer care and consider the sex of individuals when tailoring psychological support to meet specific needs.


Assuntos
Depressão , Neoplasias , Masculino , Feminino , Humanos , Pessoa de Meia-Idade , Depressão/etiologia , Depressão/diagnóstico , Depressão/epidemiologia , Qualidade de Vida , Ansiedade/etiologia , Inquéritos e Questionários , Neoplasias/terapia
2.
Phys Rev Lett ; 121(8): 081302, 2018 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-30192566

RESUMO

We evaluate the no-boundary path integral exactly in a Bianchi type IX minisuperspace with two scale factors. In this model the no-boundary proposal can be implemented by requiring one scale factor to be zero initially together with a judiciously chosen regularity condition on the momentum conjugate to the second scale factor. Taking into account the nonlinear backreaction of the perturbations we recover the predictions of the original semiclassical no-boundary proposal. In particular we find that large perturbations are strongly damped, consistent with vacuum state wave functions.

3.
Adv Biochem Eng Biotechnol ; 163: 187-206, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29071402

RESUMO

Human pluripotent stem cells (hPSCs) can acquire non-random genomic variation during culture. Some of these changes are common in tumours and confer a selective growth advantage in culture. Additionally, there is evidence that reprogramming of human induced pluripotent stem cells (hiPSCs) introduces mutations. This poses a challenge to both the safety of clinical applications and the reliability of basic research using hPSCs carrying genomic variation. A number of methods are available for monitoring the genomic integrity of hPSCs, and a balance between practicality and sensitivity must be considered in choosing the appropriate methods for each use of hPSCs. Adjusting protocols by which hPSCs are derived and cultured is an evolving process that is important in minimising acquired genomic variation. Assessing genetic variation for its potential impact is becoming increasingly important as techniques to detect genome-wide variation improve.


Assuntos
Técnicas de Reprogramação Celular/métodos , Epigênese Genética , Células-Tronco Pluripotentes Induzidas/metabolismo , Mutação , Estudo de Associação Genômica Ampla , Humanos , Células-Tronco Pluripotentes Induzidas/citologia
4.
HLA ; 90(4): 238-242, 2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-28727322

RESUMO

The HFE molecule controls iron uptake from gut, and defects in the molecule have been associated with iron overload, particularly in hereditary hemochromatosis. The HFE gene including both coding and boundary intronic regions were sequenced in 304 Brazilian individuals, encompassing healthy individuals and patients exhibiting hereditary or acquired iron overload. Six sites of variation were detected: (1) H63D C>G in exon 2, (2) IVS2 (+4) T>C in intron 2, (3) a C>G transversion in intron 3, (4) C282Y G>A in exon 4, (5) IVS4 (-44) T>C in intron 4, and (6) a new guanine deletion (G>del) in intron 5, which were used for haplotype inference. Nine HFE alleles were detected and six of these were officially named on the basis of the HLA Nomenclature, defined by the World Health Organization (WHO) Nomenclature Committee for Factors of the HLA System, and published via the IPD-IMGT/HLA website. Four alleles, HFE*001, *002, *003, and *004 exhibited variation within their exon sequences.


Assuntos
Haplótipos , Proteína da Hemocromatose/genética , Hemocromatose/genética , Sobrecarga de Ferro/genética , Polimorfismo Genético , Alelos , Sequência de Bases , Brasil , Estudos de Coortes , Éxons , Feminino , Expressão Gênica , Frequência do Gene , Humanos , Íntrons , Masculino , Pessoa de Meia-Idade , Terminologia como Assunto
5.
Tissue Antigens ; 83(1): 49-51, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24355008

RESUMO

In this article, we describe a subgroup-specific amplification assay for HLA-DQA1 that encompasses the whole coding region and allows us to sequence full-length HLA-DQA1 genes. We introduce the novel alleles HLA-DQA1*01:10 and HLA-DQA1*01:11. Moreover, we were able to confirm the full-length genomic sequence data of the alleles HLA-DQA1*01:07, HLA-DQA1*03:01:01, HLA-DQA1*03:02, HLA-DQA1*04:01:02, HLA-DQA1*04:02, HLA-DQA1*05:03, HLA-DQA1*05:05:01:02 and HLA-DQA1*06:01:01. A complete genomic overview of all six HLA-DQA1 allele groups is now available from the submission of our data to the IMGT/HLA database. Because our approach facilitates the analysis of all HLA-DQA1 allele sequences, HLA-DQA1 may become the first HLA locus from which all subgroup members will be known in detail in the near future.


Assuntos
Cadeias alfa de HLA-DQ/genética , Teste de Histocompatibilidade , Reação em Cadeia da Polimerase/métodos , Alelos , Primers do DNA/genética , Bases de Dados de Ácidos Nucleicos , Genoma , Genótipo , Humanos , Reprodutibilidade dos Testes
6.
Tissue Antigens ; 82(5): 358-9, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24131027

RESUMO

HLA-DRB1*03:85 differs from HLA-DRB1*03:06 by two nucleotides, position 257 A>T and position 258T>C, resulting in Valine at codon 57.


Assuntos
Alelos , Cadeias HLA-DRB1/genética , Sequência de Bases , Éxons/genética , Humanos , Dados de Sequência Molecular , Alinhamento de Sequência
7.
Tissue Antigens ; 81(4): 237-9, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23510426

RESUMO

The new DRB1*11:129 allele differs from the closest matching allele HLA-DRB1*11:06:01 by one nucleotide substitution in exon 3 at position 623 (G→A).


Assuntos
Alelos , Cadeias HLA-DRB1/genética , Mutação Puntual , Povo Asiático/genética , Sequência de Bases , Éxons , Cadeias HLA-DRB1/imunologia , Teste de Histocompatibilidade , Humanos , Dados de Sequência Molecular , Reação em Cadeia da Polimerase
8.
Eur J Neurosci ; 31(4): 659-72, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-20141530

RESUMO

The olfactory tubercle (OT) is found in the brains of mammals that are highly dependent on their sense of smell. Its human analogue is the poorly understood anterior perforated substance. Previous work on rat brain slices identified two types of field potential responses from the OT. The association fibre (AF) pathway was sensitive to muscarinic modulation, whereas the lateral olfactory tract (LOT) fibre pathway was not. Here, we establish that serotonin (5-hydroxytryptamine; 5-HT) also inhibits field potential excitatory postsynaptic potentials (EPSPs) in the AF, but not in the LOT fibre, pathway. Parallel experiments with adenosine (ADO) excluded ADO mediation of the 5-HT effect. Exogenous 5-HT at 30 microm caused a long-lasting approximately 40% reduction in the amplitude of AF postsynaptic responses, without affecting the time-course of EPSP decline, indicating a fairly restricted disposition of the 5-HT receptors responsible. The 5-HT(1)-preferring, 5-HT(5)-preferring and 5-HT(7)-preferring agonist 5-carboxamidotryptamine caused similar inhibition at approximately 100 nm. The 5-HT(1A)-preferring ligand 8-hydroxy-di-n-propylamino-tetralin at 10 microm, and the 5-HT uptake inhibitor citalopram at 3 microm, caused inhibition of AF-stimulated field potential responses in the 5-10% range. Order-of-potency information suggested a receptor of the 5-HT(1B) or 5-HT(1D) subtype. The 5-HT(1D) agonist L-694,247 (1 microm) suppressed the AF response by approximately 10% when used on its own. After washing out of L-694,427, inhibition by 30 microm 5-HT was reduced to negligible levels. Allowing for a partial agonist action of L-694,427 and complex interactions of 5-HT receptors within the OT, these results support the presence of active 5-HT(1D)-type receptors in the principal cell layer of the OT.


Assuntos
Antagonistas de Aminoácidos Excitatórios/farmacologia , Potenciais Pós-Sinápticos Excitadores/fisiologia , Condutos Olfatórios/metabolismo , Serotonina/farmacologia , Transmissão Sináptica/efeitos dos fármacos , 8-Hidroxi-2-(di-n-propilamino)tetralina/farmacologia , Animais , Citalopram/farmacologia , Potenciais Pós-Sinápticos Excitadores/efeitos dos fármacos , Técnicas In Vitro , Masculino , Condutos Olfatórios/efeitos dos fármacos , Oxidiazóis/farmacologia , Quinoxalinas/farmacologia , Ratos , Ratos Sprague-Dawley , Serotonina/análogos & derivados , Serotonina/metabolismo , Agonistas do Receptor de Serotonina/farmacologia , Inibidores Seletivos de Recaptação de Serotonina/farmacologia , Triptaminas/farmacologia
9.
Neurosci Lett ; 439(3): 275-80, 2008 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-18534748

RESUMO

Many studies have used the channel blocker ZD 7288 to assess possible physiological and pathophysiological roles of hyperpolarization-activated cation currents (Ih). In view of the known interplay between Ih and other membrane conductances, the effects in Wistar rats of ZD 7288 on low-voltage-activated (LVA (- or T-type)) Ca2+ channels were examined in whole-cell patch-clamp recordings from CA1 pyramidal cells in the presence of TTX, TEA, 4-AP, CsCl, BaCl2 and nifedipine. ZD 7288 reduced T-type calcium channel currents and this effect was concentration dependant. ZD 7288 blocked T-type currents when applied extracellularly, but not when included in the recording pipette. Furthermore, ZD 7288 altered the steady-state voltage-dependent inactivation of T-currents. These results indicate that the blocker ZD 7288 has effects on voltage sensitive channels additional to those reported for the Ih current.


Assuntos
Canais de Cálcio Tipo T/fisiologia , Fármacos Cardiovasculares/farmacologia , Hipocampo/citologia , Células Piramidais/efeitos dos fármacos , Pirimidinas/farmacologia , Animais , Animais Recém-Nascidos , Bloqueadores dos Canais de Cálcio/farmacologia , Relação Dose-Resposta a Droga , Relação Dose-Resposta à Radiação , Estimulação Elétrica , Técnicas In Vitro , Potenciais da Membrana/efeitos dos fármacos , Potenciais da Membrana/fisiologia , Potenciais da Membrana/efeitos da radiação , Níquel/farmacologia , Nifedipino/farmacologia , Técnicas de Patch-Clamp , Ratos , Ratos Wistar , Bloqueadores dos Canais de Sódio/farmacologia , Tetrodotoxina/farmacologia
10.
Eur J Neurosci ; 13(9): 1767-80, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-11359528

RESUMO

We have exploited the complementary arrangement of afferents in a coronal slice (300-400 microm) of the rat olfactory tubercle (OT) maintained in vitro to investigate transmission in two separate synaptic pathways. We recorded extracellular responses within the OT dense cell layer in slices and stimulated either the outermost layer to activate primary olfactory fibres or deeper to activate secondary input. Superficial stimulation produced a synaptic potential with superimposed population spike. This interpretation was based on blockade by calcium removal from the bathing medium and the use of the glutamate antagonist DNQX (10 microM); the spike was found to be selectively suppressed by tetrodotoxin applied near the cells. The spike, but not the synaptic wave, was depressed by 12 mM Ca2+ and enhanced by 1 mM Ba2+ in the bathing medium. Deep stimulation to activate association and intrinsic fibres elicited a nerve volley followed by a later response, also blocked by Ca2+ removal or 10 microM DNQX. It was unaffected by high Ca2+ or Ba2+, hence resulting from synaptic and not action current flow. Removal of Mg2+ from the bathing medium revealed an NMDA component of synaptic transmission at both loci that was selectively blocked by D-AP-5. The deep synaptic response, only, was depressed by carbachol IC50 7 microM or muscarine IC50 13 microM. This depression was also induced by AChE inhibitors eserine or tacrine and was antagonized by 1 microM atropine or 5-10 microM clozapine. These results characterize transmission in the OT and demonstrate a role for muscarinic modulation of deeper synapses in the OT that is influenced by psychotherapeutic drugs.


Assuntos
Agonistas Colinérgicos/farmacologia , Ácido Glutâmico/metabolismo , Vias Neurais/metabolismo , Neurônios/metabolismo , Condutos Olfatórios/metabolismo , Sinapses/metabolismo , Transmissão Sináptica/fisiologia , Animais , Bário/farmacologia , Antagonistas Colinérgicos/farmacologia , Inibidores da Colinesterase/farmacologia , Clozapina/farmacologia , Estimulação Elétrica , Potenciais Evocados/efeitos dos fármacos , Potenciais Evocados/fisiologia , Antagonistas GABAérgicos/farmacologia , Vias Neurais/citologia , Vias Neurais/efeitos dos fármacos , Neurônios/citologia , Neurônios/efeitos dos fármacos , Condutos Olfatórios/citologia , Condutos Olfatórios/efeitos dos fármacos , Técnicas de Cultura de Órgãos , Ratos , Sinapses/efeitos dos fármacos , Sinapses/ultraestrutura , Transmissão Sináptica/efeitos dos fármacos
11.
Cogn Psychol ; 42(4): 368-407, 2001 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11368528

RESUMO

In the literature dealing with the reanalysis of garden path sentences such as While the man hunted the deer ran into the woods, it is generally assumed either that people completely repair their initial incorrect syntactic representations to yield a final interpretation whose syntactic structure is fully consistent with the input string or that the parse fails. In a series of five experiments, we explored the possibility that partial reanalyses take place. Specifically, we examined the conditions under which part of the initial incorrect analysis persists at the same time that part of the correct final analysis is constructed. In Experiments 1a and 1b, we found that both the length of the ambiguous region and the plausibility of the ultimate interpretation affected the likelihood that such sentences would be fully reanalyzed. In Experiment 2, we compared garden path sentences with non-garden path sentences and compared performance on two different types of comprehension questions. In Experiments 3a and 3b, we constructed garden path sentences using a small class of syntactically unique verbs to provide converging evidence against the position that people employ some sort of "general reasoning" or pragmatic inference when faced with syntactically difficult garden paths. The results from these experiments indicate that reanalysis of such sentences is not always complete, so that comprehenders often derive an interpretation for the full sentence in which part of the initial misanalysis persists. We conclude that the goal of language processing is not always to create an idealized structure, but rather to create a representation that is "good enough" to satisfy the comprehender that an appropriate interpretation has been obtained.


Assuntos
Cognição , Semântica , Humanos , Tempo de Reação
12.
Brain Lang ; 79(3): 407-25, 2001 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11781051

RESUMO

Several models of comprehension deficits in agrammatic aphasia rely heavily on linear considerations in the assignment of thematic roles to structural positions (e.g., the Trace-Deletion Hypothesis, the Mapping Hypothesis, and the Argument-Linking Hypothesis). These accounts predict that constructions in languages with rules that affect syntactic structure but preserve relative linear order should be unimpaired. Other models [e.g., the Double-Dependency Hypothesis, (DDH)] do not resort to linearity but are purely structural in conception and therefore should be immune to word-order effects. We tested linear and nonlinear accounts with scrambling structures in Korean and topicalization structures in Spanish. The results are very clear. The (nonlinear) DDH is entirely compatible with the evidence, but the linear accounts are not.


Assuntos
Afasia de Broca/diagnóstico , Idioma , Adulto , Afasia de Broca/etiologia , Humanos , Testes de Linguagem , Linguística , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Índice de Gravidade de Doença
13.
J Physiol ; 506 ( Pt 1): 175-94, 1998 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-9481680

RESUMO

1. Using patch-clamp techniques, we have studied actions of dopamine and related compounds on granule neurones within the islands of Calleja in vitro, in slices if approximately 200 microns thickness or as groups of varying cell number following enzymic digestion. 2. Prior to agonist application, island of Calleja granule cells displayed spontaneous stepwise shifts in whole-cell conductance ranging from 104 to 632 pS. The reversal potentials of these conductance changes ranged widely and matched the distribution of the cells' membrane potentials. Reversal potentials and membrane potentials shifted equally when cells were uniformly depolarized in 24 mM external K+. 3. Bath-applied dopamine elicited, after a delay of 4-9 min, an exaggerated form of the spontaneous behaviour that frequently gave way to a sudden large (up to thirtyfold) conductance change. At concentrations of 100-300 nM, a range of agonists with increasing affinity for the D3 receptor (apomorphine, quinpirole, 7-OH DPAT and PD 128907) triggered the response. The actions were neither mimicked by SKF-38393 nor antagonized by SCH-23390 (a selective D1 agonist and antagonist, respectively). Haloperidol reversibly blocked responses elicited by the D3/D2 agonist quinpirole. The action of effective agonists was maintained when transmitter release was abolished. Given the reported lack of D2 receptors in the islands of Calleja, these findings indicate a direct action of dopamine at the D3 receptor. 4. The dopaminergic effects were not affected by Gd3+ or substantial replacement of external Na+ with TEA, Tris or choline, eliminating stretch-activated channels but suggesting that if transmembrane channels were to be involved in this dopaminergic action they posseses a non-selective permeability to large cations. The reported presence of gap junctions in the islands of Calleja offers the explanation that these effects derive from enhanced activity of such channels or their hemi-constituents. 5. In testing the possible involvement of gap junctional coupling the following experimental observations were made: (i) alkalinization of slices mimicked the effect of D3 agonists; (ii) in cell groups, recording from pairs provided evidence of intercellular coupling, and mechanical separation of recorded neurones from neighbouring cells during the agonist-evoked response caused shutdown of the additional conductance; (iii) when applied to slices, the gap junctional blocker, 18 alpha-glycyrrhetinic acid, whilst not preventing the full-blown dopamine response, significantly reduced both the variance of recorded granule cell input conductance and the cells' apparent capacitance. 6. Taken together the results indicate a D3 action in granule cells, which is best explained by a dopaminergic promotion of intercellular coupling. The physiological relevance of such a mechanism is discussed.


Assuntos
Junções Comunicantes/fisiologia , Prosencéfalo/citologia , Receptores de Dopamina D2/fisiologia , Animais , Agregação Celular , Dopamina/fisiologia , Agonistas de Dopamina/farmacologia , Estimulação Elétrica , Junções Comunicantes/efeitos dos fármacos , Concentração de Íons de Hidrogênio , Técnicas In Vitro , Canais Iônicos/efeitos dos fármacos , Canais Iônicos/metabolismo , Masculino , Potenciais da Membrana/fisiologia , Técnicas de Patch-Clamp , Prosencéfalo/efeitos dos fármacos , Prosencéfalo/fisiologia , Ratos , Ratos Sprague-Dawley , Receptores de Dopamina D1/efeitos dos fármacos , Receptores de Dopamina D2/agonistas , Receptores de Dopamina D3 , Tetrodotoxina/farmacologia
14.
Anal Chem ; 69(17): 3407-12, 1997 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-9286159

RESUMO

An automated enzyme assay was performed within a microfabricated channel network. Precise concentrations of substrate, enzyme, and inhibitor were mixed in nanoliter volumes using electrokinetic flow. Reagent dilution and mixing were controlled by regulating the applied potential at the terminus of each channel, using voltages derived from an equivalent circuit model of the microchip. The enzyme beta-galactosidase (beta-Gal) was assayed using resorufin beta-D-galactopyranoside (RBG), a substrate that is hydrolyzed to resorufin, a fluorescent product. Reaction kinetics were obtained by varying the concentration of substrate on-chip and monitoring the production of resorufin using laser-induced fluorescence. Derived Michaelis--Menten constants compared well between an on-chip and a conventional enzyme assay. Bias in the derived K(m) and kcat was primarily due to the limited solubility of RBG and the associated lack of measurements at substrate concentrations exceeding the K(m). A Ki of 8 microM for the inhibitor phenylethyl beta-D-thiogalactoside (PETG) was determined from plots of initial rate versus substrate concentration obtained at three concentrations of PETG. The relative inhibition of beta-Gal by lactose, p-hydroxymercuribenzoic acid, and PETG was determined by varying the inhibitor concentration with constant enzyme and substrate concentration. An enzyme assay performed on the microchip within a 20-min period required only 120 pg of enzyme and 7.5 ng of substrate, reducing the amount of reagent consumed by 4 orders of magnitude over a conventional assay.


Assuntos
Enzimas/análise , Microcomputadores , Autoanálise/instrumentação , Autoanálise/métodos , Indicadores e Reagentes
16.
J Physiol ; 487 ( Pt 2): 421-40, 1995 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-8558474

RESUMO

1. Using patch-clamp techniques, we have studied granule neurones from the islands of Calleja in vitro: as isolated cells or as groups of varying numbers following enzymic digestion, or within untreated slices of approximately 100 microns thickness. 2. Recordings were made with patch pipettes in conventional or nystatin-perforated whole-cell mode. Current-clamp recordings indicated that these granule cells are excitable and at resting potential produce irregular spontaneous activity. In voltage clamp the transient inward current underlying these action potentials could be evoked. This current had a threshold for activation of about -50 mV and was sensitive to TTX. In some cells a TTX-resistant transient inward current was observed with a threshold for activation of about -70 mV. 3. Island of Calleja granule cells also exhibited outward currents. A rapidly activating transient current was observed that was resistant to TEA and sensitive to 4-AP, and therefore resembled IA. The current was half-maximally activated at -6 mV and steady-state inactivation was half-complete at -65 mV. 4. More sustained outward currents were also observed. Although some cells appeared to express a Ca(2+)-activated K+ current, the most common finding was a rapidly activating, slowly inactivating, voltage-dependent K+ current that was sensitive to TEA and Ba2+. This current resembled M-current more than delayed rectifier but displayed a number of idiosyncratic kinetic properties. Chief amongst these was the accumulation of an inactivating process when the current was repeatedly evoked from potentials near the cells' resting value by voltage steps that by themselves produced no observable inactivation during the voltage command; this behaviour was similar to the 'C-terminal' inactivation exhibited by lymphocytes and certain expressed K+ channel clones (Kv1.3). 5. These results indicate that the granule cells of the islands of Calleja are excitable and contain a number of additional regulatory conductances. The implications of these findings in, and the usefulness of this preparation to, the elucidation of the function(s) of the islands of Calleja are discussed.


Assuntos
Cálcio/metabolismo , Condutos Olfatórios/metabolismo , Potássio/metabolismo , Animais , Permeabilidade da Membrana Celular/efeitos dos fármacos , Técnicas In Vitro , Masculino , Potenciais da Membrana/efeitos dos fármacos , Condutos Olfatórios/citologia , Condutos Olfatórios/efeitos dos fármacos , Técnicas de Patch-Clamp , Ratos , Ratos Sprague-Dawley , Tetraetilamônio , Compostos de Tetraetilamônio/farmacologia , Tetrodotoxina/farmacologia
17.
Phys Rev Lett ; 74(2): 203-207, 1995 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-10058329
18.
Neurosci Lett ; 168(1-2): 106-10, 1994 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-8028759

RESUMO

Synaptic transmission in the CA1 area of the hippocampal slice preparation in vitro was studied in bathing media containing different levels of divalent cations. Transmission was abolished by replacing the normal levels (2.5 mM) of Ca2+ with 3 mM Mg. Transmission was not permanently restored by subsequent addition of Ba2+ but added Ca2+ was effective. Transient reappearance of synaptic currents were seen when Ba2+ was added at a time when contaminating levels of Ca2+ were still present, but neurotransmission waned as [Ca2+]e declined with protracted washout. In accordance with this interpretation, Ba2+ potentiated the transmission observed in the presence of low concentrations (0.25 mM) of Ca2+. Little evidence was found for Ba2+ effects at axonal sites but the potentiation of synaptic transmission by Ba2+ could be accounted for in terms of a blockade of terminal K-channels.


Assuntos
Bário/farmacologia , Hipocampo/fisiologia , Sinapses/fisiologia , Transmissão Sináptica/fisiologia , Potenciais de Ação/efeitos dos fármacos , Potenciais de Ação/fisiologia , Animais , Cálcio/farmacologia , Relação Dose-Resposta a Droga , Potenciais Evocados/efeitos dos fármacos , Potenciais Evocados/fisiologia , Técnicas In Vitro , Masculino , Ratos , Ratos Sprague-Dawley , Sinapses/efeitos dos fármacos , Transmissão Sináptica/efeitos dos fármacos , Fatores de Tempo
19.
J Anat ; 184 ( Pt 1): 111-7, 1994 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-8157483

RESUMO

Intracellular injection of a biotinylated probe in fixed superior cervical ganglia followed by confocal microscopy was used to investigate the effects of age on the dendritic arborisation of sympathetic neurons in rats aged 6 wk (young adult), 7 months (fully grown adult) and 24 months (aged). In accordance with other studies considerable dendritic growth was observed during postnatal development. However, in old age dendritic growth did not continue, and significant atrophy was observed. Quantitation of neuronal morphology showed significant reductions in soma size, total dendritic length, number of branch points and total area of dendritic arborisation in old age. Unexpectedly, significant reductions in the numbers of primary dendrites were observed in maturity and in old age. Concomitant with this atrophy there was an increase in age-related morphological abnormalities. The similarities between the atrophy and dendritic abnormalities shown by our aged neurons and those seen in other studies of young adult sympathetic neurons following axotomy or trophic factor deprivation are discussed.


Assuntos
Envelhecimento/fisiologia , Dendritos/ultraestrutura , Gânglio Cervical Superior/ultraestrutura , Animais , Dendritos/fisiologia , Masculino , Ratos , Ratos Sprague-Dawley
20.
Eur J Neurosci ; 5(9): 1198-209, 1993 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-8281323

RESUMO

Intracellular recordings were made from CA1 neurons in rat hippocampal slices maintained in vitro. When Na+ currents were blocked with tetrodotoxin and K+ conductances known to be sensitive to suppression by muscarinic agonists were blocked by 2 mM Ba2+, CA1 cells were depolarized by carbachol (3-10 microM) with an attendant conductance increase, whereas prior to Ba2+ the agonist produced a decrease or no change in conductance. Under voltage clamp at approximately -60 mV and in the presence of tetrodotoxin and Ba2+, carbachol (3-10 microM) induced a variable-latency biphasic inward current of up to 380 pA associated with a conductance increase of approximately 50%. The first phase was associated with an increase (more than 2-fold) of the Cs(+)-sensitive, hyperpolarization-activated cationic current, IQ. Carbachol also accelerated the kinetics of IQ at -100 mV with an average 24% reduction in its activation time constant. The second phase reflected an additional inward current that was Cs(+)-resistant, displayed little apparent voltage sensitivity and had a mean extrapolated reversal potential, determined in the presence of external Cs+ (< or = 5 mM), of approximately -20 mV. In a small proportion of cells the second phase of inward current was followed (or overlapped) by an outward current, also associated with a conductance increase, which reversed at approximately -70 mV. These carbachol actions were prevented by extracellular 300 microM Cd2+ and 2 mM Mn2+, by high levels (> 5 mM) of extracellular Mg2+ or Ca2+, and by omission of Ca2+ or reduction of extracellular Na+ to 25 mM by substitution of NaCl with Tris or N-methyl-D-glucamine. Carbachol action was not mimicked by oxotremorine (< or = 60 microM), but was irreversibly blocked by this drug. Likewise, atropine (100 nM) irreversibly and gallamine (10 microM) reversibly antagonized carbachol's action. The action of carbachol was blocked shortly after prior exposure of slices to 2-5 mM caffeine. Chronic or acute incubation of slices with 2 mM Li+ potentiated (between 1- and 2-fold) carbachol responses. The data indicate that muscarinic activation increases cationic flux by a calcium-dependent potentiation of IQ and activation of a non-selective conductance. The probability that inositol phospholipid metabolism is involved in triggering these events is discussed.


Assuntos
Cálcio/fisiologia , Carbacol/farmacologia , Hipocampo/fisiologia , Animais , Atropina/farmacologia , Bário/farmacologia , Cátions/metabolismo , Condutividade Elétrica , Eletrofisiologia , Trietiodeto de Galamina/farmacologia , Hipocampo/citologia , Hipocampo/efeitos dos fármacos , Técnicas In Vitro , Membranas Intracelulares/fisiologia , Íons , Masculino , Neurônios/fisiologia , Ratos , Ratos Sprague-Dawley
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