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1.
J Hosp Palliat Nurs ; 24(1): 50-56, 2022 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-34550916

RESUMO

During the coronavirus disease 2019 (COVID-19) pandemic, patients experienced rapid clinical decline requiring urgent conversations about their wishes for care. Palliative care advanced practice registered nurses developed a workflow to provide early palliative care consultation to every COVID-19 patient under investigation admitted to a 368-bed acute care hospital in the United States. A retrospective exploratory study was conducted on the initial surge from March 1 to May 31 of 2020. A nonrandomized 2-group design used descriptive and inferential statistics to compare elicitation of patient care preferences for patients who received early palliative care consultation with those patients who did not receive a palliative care consult. Early palliative care consultation resulted in a higher number of patients establishing a decision-maker (99%), changing code status (46%), changing goals of care (46%), and transitioning to comfort care (24%). In those patients not receiving palliative care, fewer patients established a decision-maker (10%), changed code status (7%), changed goals of care (4%), or transitioned to comfort care (3%). During the first COVID-19 surge, early palliative care consult performed by advanced practice registered nurses resulted in a higher number of patients establishing decision-makers and changing care preferences before decompensation due to COVID-19, thus helping patients avoid potential suffering caused by unwanted medical interventions.


Assuntos
COVID-19 , Pandemias , Humanos , Cuidados Paliativos , Encaminhamento e Consulta , Estudos Retrospectivos , SARS-CoV-2
2.
Environ Sci Technol ; 55(6): 3898-3908, 2021 03 16.
Artigo em Inglês | MEDLINE | ID: mdl-33411509

RESUMO

Molten salt reactors (MSRs) have the potential to safely support green energy goals while meeting baseload energy needs with diverse energy portfolios. While reactor designers have made tremendous strides with these systems, licensing and deployment of these reactors will be aided through the development of new technology such as on-line and remote monitoring tools. Of particular interest is quantifying reactor off-gas species, such as iodine, within off-gas streams to support the design and operational control of off-gas treatment systems. Here, the development of advanced Raman spectroscopy systems for the on-line analysis of gas composition is discussed, focusing on the key control species I2(g). Signal response was explored with two Raman instruments, utilizing 532 and 671 nm excitation sources, as a function of I2(g) pressure and temperature. Also explored is the integration of advanced data analysis methods to enable real-time and highly accurate analysis of complex optical data. Specifically, the application of chemometric modeling is discussed. Raman spectroscopy paired with chemometric analysis is demonstrated to provide a powerful route to analyzing I2(g) composition within the gas phase, which lays the foundation for applications within molten salt reactor off-gas analysis and other significant chemical processes producing iodine species.


Assuntos
Iodo , Análise Espectral Raman , Espectrometria de Fluorescência
3.
Can Respir J ; 19(1): e3-4, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22332139

RESUMO

Acute exacerbations of interstitial lung disease present as clinical deteriorations, with progressive hypoxemia and parenchymal consolidation not related to infection, heart failure or thromboembolic disease. Following single lung transplantation, patients receive maintenance immunosuppression, which could mitigate the development of acute exacerbations in the native lung. A 66-year-old man with fibrotic, nonspecific interstitial pneumonitis presented with fever, hypoxemia and parenchymal consolidation limited to the native lung four years after single lung transplantation. Investigations were negative for infection, heart failure and thromboembolic disease. The patient worsened over the course of one week despite broad-spectrum antimicrobial therapy, but subsequently improved promptly with augmentation of prednisone dosed to 50 mg daily and addition of N-acetylcysteine. Hence, the patient fulfilled the criteria for a diagnosis of an acute exacerbation of pulmonary fibrosis in his native lung. Clinicians should consider acute exacerbation of parenchymal lung disease of the native lung in the differential diagnosis of progressive respiratory deterioration following single lung transplantation for pulmonary fibrosis.


Assuntos
Acetilcisteína/uso terapêutico , Doenças Pulmonares Intersticiais/diagnóstico , Transplante de Pulmão , Pulmão/patologia , Prednisona/uso terapêutico , Fibrose Pulmonar/diagnóstico , Idoso , Humanos , Pulmão/diagnóstico por imagem , Doenças Pulmonares Intersticiais/terapia , Masculino , Complicações Pós-Operatórias , Fibrose Pulmonar/tratamento farmacológico , Tomografia Computadorizada por Raios X
4.
Can Respir J ; 18(4): e64-5, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-22059186
5.
J Neurosci ; 30(3): 1137-48, 2010 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-20089922

RESUMO

To ensure alternation of flexor and extensor muscles during locomotion, the spinal locomotor network provides rhythmic inhibition to motoneurons. The source of this inhibition in mammals is incompletely defined. We have identified a population of GABAergic interneurons located in medial laminae V/VI that express green fluorescent protein (GFP) in glutamic acid decarboxylase-65::GFP transgenic mice. Immunohistochemical studies revealed GFP+ terminals in apposition to motoneuronal somata, neurons in Clarke's column, and in laminae V/VI where they apposed GFP+ interneurons, thus forming putative reciprocal connections. Whole-cell patch-clamp recordings from GFP+ interneurons in spinal cord slices revealed a range of electrophysiological profiles, including sag and postinhibitory rebound potentials. Most neurons fired tonically in response to depolarizing current injection. Calcium transients demonstrated by two-photon excitation microscopy in the hemisected spinal cord were recorded in response to low-threshold dorsal root stimulation, indicating these neurons receive primary afferent input. Following a locomotor task, the number of GFP+ neurons expressing Fos increased, indicating that these neurons are active during locomotion. During fictive locomotion induced in the hemisected spinal cord, two-photon excitation imaging demonstrated rhythmic calcium activity in these interneurons, which correlated with the termination of ventral root bursts. We suggest that these dorsomedial GABAergic interneurons are involved in spinal locomotor networks, and may provide direct rhythmic inhibitory input to motoneurons during locomotion.


Assuntos
Interneurônios/fisiologia , Locomoção/genética , Inibição Neural/genética , Periodicidade , Medula Espinal/citologia , Potenciais de Ação/efeitos dos fármacos , Potenciais de Ação/genética , Animais , Animais Recém-Nascidos , Colina O-Acetiltransferase/metabolismo , Dextranos/metabolismo , Estimulação Elétrica/métodos , Glutamato Descarboxilase/genética , Proteínas de Fluorescência Verde/genética , Técnicas In Vitro , Interneurônios/classificação , Camundongos , Camundongos Transgênicos , Técnicas de Patch-Clamp/métodos , Proteínas Proto-Oncogênicas c-fos/metabolismo , Rodaminas/metabolismo , Ácido gama-Aminobutírico/metabolismo
6.
Dev Dyn ; 238(11): 2787-99, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19842178

RESUMO

There is scant information on the fate of cardiac progenitor cells (CPC) in the embryonic heart after chamber specification. Here we simultaneously tracked three lineage-specific markers (Nkx2.5, MLC2v, and ANF) and confirmed that CPCs with an Nkx2.5+MLC2v-ANF- phenotype are present in the embryonic (E) day 11.5 mouse ventricular myocardium. We demonstrated that these CPCs could give rise to working cardiomyocytes and conduction system cells. Using a two-photon imaging analysis, we found that the majority of CPCs are not capable of developing Ca2+ transients in response to beta-adrenergic receptor stimulation. In contrast, Nkx2.5+ cells expressing MLC2v but not ANF are capable of developing functional Ca2+ transients. We showed that Ca2+ transients could be invoked in Nkx2.5+MLC2v+ANF+ cells only upon inhibition of Gi, muscarinic receptors, or nitric oxide synthase (NOS) signaling pathways. Our data suggest that these inhibitory pathways may delay functional specification in a subset of developing ventricular cells.


Assuntos
Canais de Cálcio/metabolismo , Cálcio/metabolismo , Embrião de Mamíferos/embriologia , Ventrículos do Coração/embriologia , Mioblastos Cardíacos/metabolismo , Miócitos Cardíacos/metabolismo , Animais , Fator Natriurético Atrial/metabolismo , Embrião de Mamíferos/metabolismo , Ventrículos do Coração/metabolismo , Ventrículos do Coração/ultraestrutura , Proteína Homeobox Nkx-2.5 , Proteínas de Homeodomínio/metabolismo , Camundongos , Microscopia Eletrônica de Transmissão , Mioblastos Cardíacos/ultraestrutura , Miocárdio/metabolismo , Miocárdio/ultraestrutura , Miócitos Cardíacos/ultraestrutura , Cadeias Leves de Miosina/metabolismo , Óxido Nítrico Sintase/metabolismo , Receptores Adrenérgicos beta/metabolismo , Receptores Muscarínicos/metabolismo , Transdução de Sinais/fisiologia , Fatores de Transcrição/metabolismo
7.
Brain Res Rev ; 57(1): 64-76, 2008 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-17905441

RESUMO

Despite significant advances in our understanding of pattern generation in invertebrates and lower vertebrates, there have been barriers to the application of the principles learned to the definition of networks underlying mammalian locomotion. Major difficulties have arisen in identifying spinal interneurones in preparations which allow study of neuronal intrinsic properties and the role of identified interneurones in locomotor networks. Recent genetic technologies in which selective expression of fluorescent proteins in specific populations of mouse spinal neurones have provided new avenues of investigation. In this review, we focus on the generation of locomotor rhythm and outline criteria that rhythm-generating neurones might be expected to fulfill. We then examine the extent to which a recently identified population of spinal interneurones, Hb9 interneurones, fulfill these criteria. Finally, we suggest that Hb9 interneurones could be involved in an asymmetric model of locomotor rhythmogenesis through projections of electrotonically coupled rhythm-generating modules to flexor pattern formation half-centres. The principles learned from studying this population of interneurones have led to strategies to systematically evaluate neurones that may be involved in locomotor rhythmogenesis.


Assuntos
Instinto , Interneurônios/fisiologia , Locomoção/fisiologia , Rede Nervosa/fisiologia , Medula Espinal/fisiologia , Animais , Eletrofisiologia , Humanos , Modelos Neurológicos , Biologia Molecular , Rede Nervosa/citologia , Medula Espinal/citologia
8.
Org Biomol Chem ; 5(22): 3651-6, 2007 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-17971994

RESUMO

A short, highly efficient approach for the synthesis of a novel class of polyazamacrocycles containing N-functionalised carbamate side-chains has been developed. The key steps involved a phase-transfer mediated macrocyclisation to form the ring system as well as a tin-catalysed reaction with isocyanates to introduce the carbamate side-chains. X-Ray crystallography confirmed successful formation of the 1,4,7,10-tetraazacyclododecane ring and N-functionalisation of all the amine centres. Preliminary testing of the biological activity of the compounds revealed significant anti-parasitic activity against bloodstream form African trypanosomes.


Assuntos
Antiprotozoários/síntese química , Antiprotozoários/farmacologia , Carbamatos/química , Compostos Macrocíclicos/síntese química , Compostos Macrocíclicos/farmacologia , Animais , Antiprotozoários/química , Carbamatos/síntese química , Carbamatos/farmacologia , Linhagem Celular , Humanos , Compostos Macrocíclicos/química , Testes de Sensibilidade Parasitária , Trypanosoma brucei brucei/efeitos dos fármacos
9.
J Neurophysiol ; 97(4): 3118-25, 2007 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-17303810

RESUMO

Fluorescent protein (XFP) expression in postnatal neurons allows the anatomical and physiological investigation of identified subpopulations of interneurons with established techniques. However, the spatiotemporal pattern of activity of these XFP neurons within a network and their role in the functional output of the network are more challenging issues to investigate. Here we apply two-photon excitation laser scanning microscopy to mouse spinal cord locomotor networks and present the methodology by which calcium activity can be recorded in XFP-expressing neurons. Such activity can be studied both in relation to neighboring non-XFP neurons in a spinal cord slice preparation and in relation to functional locomotor output monitored by ventral root activity in the intact in vitro spinal cord. Thus the network properties and functional correlates with locomotion of identified populations of interneurons can be studied simultaneously.


Assuntos
Sinalização do Cálcio/fisiologia , Proteínas de Fluorescência Verde/biossíntese , Proteínas Luminescentes/biossíntese , Microscopia Confocal/métodos , Rede Nervosa/anatomia & histologia , Neurônios/fisiologia , Animais , Corantes , Interpretação Estatística de Dados , Glutamato Descarboxilase/metabolismo , Proteínas de Fluorescência Verde/genética , Interneurônios/fisiologia , Locomoção/fisiologia , Proteínas Luminescentes/genética , Camundongos , Camundongos Endogâmicos ICR , Camundongos Transgênicos , Rede Nervosa/citologia , Rede Nervosa/fisiologia , Medula Espinal/metabolismo , Ácido gama-Aminobutírico/fisiologia
10.
Bioorg Med Chem ; 15(1): 77-86, 2007 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-17064912

RESUMO

A family of 5-deazaflavin derivatives has been synthesised using a two-step convergent strategy. The biological activity of these compounds was evaluated in cells, by assessing their ability to stabilize and activate p53. These compounds may act as low molecular weight inhibitors of the E3 activity of HMD2 in tumours that retain wild-type p53. Importantly, we have demonstrated that the nitro group present in all three of the original lead compounds [1-3 (HL198C-E)] is not essential for observation of this biological activity.


Assuntos
Células Epiteliais/efeitos dos fármacos , Flavinas/síntese química , Flavinas/farmacologia , Proteína Supressora de Tumor p53/efeitos dos fármacos , Apoptose/efeitos dos fármacos , Western Blotting , Ciclo Celular/efeitos dos fármacos , Dano ao DNA , Relação Dose-Resposta a Droga , Doxorrubicina/farmacologia , Avaliação Pré-Clínica de Medicamentos , Células Epiteliais/química , Células Epiteliais/metabolismo , Flavinas/química , Citometria de Fluxo , Humanos , Estrutura Molecular , Peso Molecular , Proteínas Proto-Oncogênicas c-mdm2/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-mdm2/fisiologia , Sensibilidade e Especificidade , Estereoisomerismo , Relação Estrutura-Atividade , Proteína Supressora de Tumor p53/metabolismo
11.
J Recept Signal Transduct Res ; 26(3): 179-98, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16777714

RESUMO

We report the detailed expression profile of TRPM2 mRNA within the human central nervous system (CNS) and demonstrate increased TRPM2 mRNA expression at 1 and 4 weeks following ischemic injury in the rat transient middle cerebral artery occlusion (tMCAO) stroke model. Microglial cells play a key role in pathology produced following ischemic injury in the CNS and possess TRPM2, which may contribute to stroke-related pathological responses. We show that TRPM2 mRNA is present in the human C13 microglial cell line and is reduced by antisense treatment. Activation of C13 cells by interleukin-1beta leads to a fivefold increase of TRPM2 mRNA demonstrating transcriptional regulation. To confirm mRNA distribution correlated with functional expression, we combined electrophysiology, Ca2+ imaging, and antisense approaches. C13 microglia exhibited, when stimulated with hydrogen peroxide (H2O2), increased [Ca2+]i, which was reduced by antisense treatment. Moreover, patch-clamp recordings from C13 demonstrated that increased intracellular adenosine diphosphoribose (ADPR) or extracellular H2O2 induced an inward current, consistent with activation of TRPM2. In addition we confirm the functional expression of a TRPM2-like conductance in primary microglial cultures derived from rats. Activation of TRPM2 in microglia during ischemic brain injury may mediate key aspects of microglial pathophysiological responses.


Assuntos
Microglia/metabolismo , Acidente Vascular Cerebral/genética , Acidente Vascular Cerebral/metabolismo , Canais de Cátion TRPM/genética , Canais de Cátion TRPM/metabolismo , Animais , Sequência de Bases , Sinalização do Cálcio/efeitos dos fármacos , Linhagem Celular , Sistema Nervoso Central/metabolismo , Modelos Animais de Doenças , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Peróxido de Hidrogênio/farmacologia , Interleucina-1/farmacologia , Masculino , Microglia/efeitos dos fármacos , Artéria Cerebral Média , RNA Antissenso/administração & dosagem , RNA Antissenso/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ratos , Ratos Sprague-Dawley , Distribuição Tecidual
12.
J Neurosci ; 25(24): 5710-9, 2005 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-15958737

RESUMO

The properties of mammalian spinal interneurons that underlie rhythmic locomotor networks remain poorly described. Using postnatal transgenic mice in which expression of green fluorescent protein is driven by the promoter for the homeodomain transcription factor Hb9, as well as Hb9-lacZ knock-in mice, we describe a novel population of glutamatergic interneurons located adjacent to the ventral commissure from cervical to midlumbar spinal cord levels. Hb9+ interneurons exhibit strong postinhibitory rebound and demonstrate pronounced membrane potential oscillations in response to chemical stimuli that induce locomotor activity. These data provide a molecular and physiological delineation of a small population of ventral spinal interneurons that exhibit homogeneous electrophysiological features, the properties of which suggest that they are candidate locomotor rhythm-generating interneurons.


Assuntos
Proteínas de Homeodomínio/genética , Interneurônios/fisiologia , Medula Espinal/fisiologia , Fatores de Transcrição/genética , Animais , Bovinos , Eletrofisiologia , Regulação da Expressão Gênica , Proteínas de Fluorescência Verde/genética , Hormônio do Crescimento/genética , Imuno-Histoquímica , Hibridização In Situ , Camundongos , Camundongos Transgênicos , Regiões Promotoras Genéticas , Splicing de RNA , Recombinação Genética , beta-Galactosidase/genética
13.
J Comp Neurol ; 474(1): 13-23, 2004 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-15156576

RESUMO

Following birth, when mammals are relatively immobile, significant development of the motor system facilitates weight bearing and locomotion. Prominent cholinergic C-terminals develop on somata and proximal dendrites of spinal motoneurons during this time period. It is hypothesized that these terminals are essential in regulating motoneuron excitability and thus their development contributes to motor system maturation. Therefore, the development of pre- and postsynaptic components of the C-terminal synapse on motoneurons in mice during the early postnatal period was investigated. Fluorescence immunohistochemical studies revealed that developmental increases in punctate labeling of presynaptic cholinergic terminals, as visualized by vesicular acetylcholine transporter immunoreactivity (VAChT-IR) corresponded to the progressive expression and spatial restriction of immunoreactivity for the calcium channel subunit alpha(1)2.2 (N-type) located presynaptically and the muscarinic type 2 acetylcholine receptor situated postsynaptically. In addition, clustering of immunoreactivity for the potassium channel subunit K(V)2.1 occurred within the early postnatal period in concert and colocalized with the maturation of the C-terminals. The time course of development of these components of the C-terminal synapse corresponds to the maturation of the motor system that enables the animal to locomote in an adult-like fashion.


Assuntos
Acetilcolina/metabolismo , Envelhecimento/fisiologia , Proteínas de Membrana Transportadoras , Neurônios Motores/fisiologia , Medula Espinal/citologia , Sinapses/fisiologia , Proteínas de Transporte Vesicular , Animais , Animais Recém-Nascidos , Canais de Cálcio/metabolismo , Proteínas de Transporte/metabolismo , Colina O-Acetiltransferase/metabolismo , Corantes Fluorescentes/metabolismo , Imuno-Histoquímica/métodos , Camundongos , Camundongos Endogâmicos BALB C , Microscopia Confocal/métodos , Neurônios Motores/metabolismo , Canais de Potássio/metabolismo , Receptores Muscarínicos/metabolismo , Medula Espinal/crescimento & desenvolvimento , Estilbamidinas/metabolismo , Proteínas Vesiculares de Transporte de Acetilcolina
14.
J Physiol ; 555(Pt 1): 189-203, 2004 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-14673187

RESUMO

The role of GABA receptors in synaptic transmission to neonatal rat sympathetic preganglionic neurones (SPNs) was investigated utilizing whole-cell patch clamp recording techniques in longitudinal and transverse spinal cord slice preparations. In the presence of glutamate receptor antagonists (NBQX, 5 microm and D-APV, 10 microm), electrical stimulation of the ipsilateral or contralateral lateral funiculi (iLF and cLF, respectively) revealed monosynaptic inhibitory postsynaptic potentials (IPSPs) in 75% and 65% of SPNs, respectively. IPSPs were sensitive to bicuculline (10 microM) in all neurones tested and reversed polarity around -55 mV, the latter indicating mediation via chloride conductances. In three neurones IPSPs evoked by stimulation of the iLF (n = 1) or cLF (n = 2) were partly sensitive to strychnine (2 microM). The expression of postsynaptic GABA(A) and GABA(B) receptors were confirmed by the sensitivity of SPNs to agonists, GABA (2 mm), muscimol (10-100 microM) or baclofen (10-100 microM), in the presence of TTX, each of which produced membrane hyperpolarization in all SPNs tested. Muscimol-induced responses were sensitive to bicuculline (1-10 microM) and SR95531 (10 microM) and baclofen-induced responses were sensitive to 2-hydroxy-saclofen (100-200 microM) and CGP55845 (200 nM). The GABA(C) receptor agonist CACA (200 microM) was without significant effect on SPNs. These results suggest that SPNs possess postsynaptic GABA(A) and GABA(B) receptors and that subsets of SPNs receive bilateral GABAergic inputs which activate GABA(A) receptors, coupled to a chloride conductance. At resting or holding potentials close to threshold either single or bursts (10-100 Hz) of IPSPs gave rise to a rebound excitation and action potential firing at the termination of the burst. This effect was mimicked by injection of small (10-20 pA) rectangular-wave current pulses, which revealed a time-dependent, Cs(+)-sensitive inward rectification and rebound excitation at the termination of the response to current injection. Synaptic activation of a rebound excitation mediated by a time-dependent inward rectification expressed intrinsically by SPNs may provide a novel mechanism enabling SPNs to be entrained to rhythms driven from the brainstem or higher centres.


Assuntos
Fibras Autônomas Pré-Ganglionares/fisiologia , Receptores de GABA-A/fisiologia , Receptores de GABA-B/fisiologia , Sinapses/fisiologia , Fibras Adrenérgicas/efeitos dos fármacos , Fibras Adrenérgicas/fisiologia , Animais , Animais Recém-Nascidos , Fibras Autônomas Pré-Ganglionares/efeitos dos fármacos , Feminino , Agonistas GABAérgicos/farmacologia , Agonistas de Receptores de GABA-A , Agonistas dos Receptores de GABA-B , Técnicas In Vitro , Masculino , Ratos , Ratos Endogâmicos WKY , Ratos Sprague-Dawley , Sinapses/efeitos dos fármacos , Ácido gama-Aminobutírico/farmacologia , Ácido gama-Aminobutírico/fisiologia
15.
J Physiol ; 545(3): 945-60, 2002 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-12482898

RESUMO

The intravascular release of adrenal catecholamines is a fundamental homeostatic process mediated via thoracolumbar spinal sympathetic preganglionic neurones (AD-SPN). To understand mechanisms regulating their excitability, whole-cell patch-clamp recordings were obtained from 54 retrogradely labelled neonatal rat AD-SPN. Passive membrane properties included a mean resting membrane potential, input resistance and time constant of -62 +/- 6 mV, 410 +/- 241 MOmega and 104 +/- 53 ms, respectively. AD-SPN were homogeneous with respect to their active membrane properties. These active conductances included transient outward rectification, observed as a delayed return to rest at the offset of the membrane response to hyperpolarising current pulses, with two components: a fast 4-AP-sensitive component (A-type conductance), contributing to the after-hyperpolarisation (AHP) and spike repolarisation; a slower prolonged Ba(2+)-sensitive component (D-like conductance). All AD-SPN expressed a Ba(2+)-sensitive instantaneous inwardly rectifying conductance activated at membrane potentials more negative than around -80 mV. A potassium-mediated, voltage-dependent sustained outward rectification activated at membrane potentials between -35 and -15 mV featured an atypical pharmacology with a component blocked by quinine, reduced by low extracellular pH and arachidonic acid, but lacking sensitivity to Ba(2+), TEA and intracellular Cs(+). This quinine-sensitive outward rectification contributes to spike repolarisation. Following block of potassium conductances by Cs(+) loading, AD-SPN revealed the capability for autorhythmicity and burst firing, mediated by a T-type Ca(2+) conductance. These data suggest the output capability is dynamic and diverse, and that the range of intrinsic membrane conductances expressed endow AD-SPN with the ability to generate differential and complex patterns of activity. The diversity of intrinsic membrane properties expressed by AD-SPN may be key determinants of neurotransmitter release from SPN innervating the adrenal medulla. However, factors other than active membrane conductances of AD-SPN must ultimately regulate the differential ratio of noradrenaline (NA) versus adrenaline (A) release secreted in response to various physiological and environmental demands.


Assuntos
Medula Suprarrenal/inervação , Fibras Autônomas Pré-Ganglionares/fisiologia , Neurônios/fisiologia , Animais , Animais Recém-Nascidos , Fibras Autônomas Pré-Ganglionares/efeitos dos fármacos , Cálcio/fisiologia , Membrana Celular/fisiologia , Eletrofisiologia , Técnicas In Vitro , Vértebras Lombares , Neurônios/efeitos dos fármacos , Técnicas de Patch-Clamp , Bloqueadores dos Canais de Potássio/farmacologia , Ratos , Medula Espinal/efeitos dos fármacos , Medula Espinal/fisiologia , Sistema Nervoso Simpático/efeitos dos fármacos , Sistema Nervoso Simpático/fisiologia , Vértebras Torácicas
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