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1.
Mil Med ; 185(Suppl 1): 103-109, 2020 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-32074312

RESUMO

INTRODUCTION: Blood is a precious commodity, with storage limited to 42 days under refrigeration. Degradative changes in red blood cells (RBCs) begin as early as 11-21 days after collection, and compromise their function. Materials that extend the life of RBCs will improve blood utilization in the field, as well as in hospital settings. Cerium oxide nanoparticles (CeONPs) are widely used in the materials industry to counteract oxidative stress and improve oxygen storage. We have previously shown that CeONPs extended the lifespan of cells in culture and counteract oxidative stress in vitro and in vivo. Here, we test the hypothesis that CeONPs extend the lifespan of RBCs in whole stored blood. MATERIALS AND METHODS: Rat whole blood was collected with sodium citrate and stored at 4°C. Groups consisted of control (no CeONPs), and 10 and 100 nM CeONPs (average particle size 10 nm) added. Aliquots of stored blood were removed weekly and analyzed for different blood parameters. RESULTS: Results demonstrate that CeONPs improve storage and functional lifespan of RBCs in stored whole blood. CONCLUSIONS: This work suggests that CeONPs may be a promising additive for extending storage and function of blood and blood products.


Assuntos
Sangue/efeitos dos fármacos , Cério/uso terapêutico , Longevidade/efeitos dos fármacos , Animais , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/fisiologia , Cério/farmacologia , Modelos Animais de Doenças , Armazenamento de Medicamentos/métodos , Armazenamento de Medicamentos/estatística & dados numéricos , Nanopartículas/uso terapêutico , Ratos
2.
J Neurotrauma ; 37(12): 1452-1462, 2020 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-27733104

RESUMO

Mild traumatic brain injury results in aberrant free radical generation, which is associated with oxidative stress, secondary injury signaling cascades, mitochondrial dysfunction, and poor functional outcome. Pharmacological targeting of free radicals with antioxidants has been examined as an approach to treatment, but has met with limited success in clinical trials. Conventional antioxidants that are currently available scavenge a single free radical before they are destroyed in the process. Here, we report for the first time that a novel regenerative cerium oxide nanoparticle antioxidant reduces neuronal death and calcium dysregulation after in vitro trauma. Further, using an in vivo model of mild lateral fluid percussion brain injury in the rat, we report that cerium oxide nanoparticles also preserve endogenous antioxidant systems, decrease macromolecular free radical damage, and improve cognitive function. Taken together, our results demonstrate that cerium oxide nanoparticles are a novel nanopharmaceutical with potential for mitigating neuropathological effects of mild traumatic brain injury and modifying the course of recovery.


Assuntos
Concussão Encefálica/tratamento farmacológico , Concussão Encefálica/patologia , Cério/administração & dosagem , Nanopartículas/administração & dosagem , Animais , Animais Recém-Nascidos , Concussão Encefálica/metabolismo , Sinalização do Cálcio/efeitos dos fármacos , Sinalização do Cálcio/fisiologia , Células Cultivadas , Técnicas In Vitro , Masculino , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Neurônios/patologia , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/fisiologia , Ratos , Ratos Sprague-Dawley , Resultado do Tratamento
3.
Proc Natl Acad Sci U S A ; 116(24): 11839-11844, 2019 06 11.
Artigo em Inglês | MEDLINE | ID: mdl-31127048

RESUMO

Biodiversity refugia formed by unique features of the Mediterranean arid landscape, such as the dramatic ecological contrast of "Evolution Canyon," provide a natural laboratory in which local adaptations to divergent microclimate conditions can be investigated. Significant insights have been provided by studies of Drosophila melanogaster diversifying along the thermal gradient in Evolution Canyon, but a comparative framework to survey adaptive convergence across sister species at the site has been lacking. To fill this void, we present an analysis of genomic polymorphism and evolutionary divergence of Drosophila simulans, a close relative of Drosophila melanogaster with which it co-occurs on both slopes of the canyon. Our results show even deeper interslope divergence in D. simulans than in D. melanogaster, with extensive signatures of selective sweeps present in flies from both slopes but enhanced in the population from the hotter and drier south-facing slope. Interslope divergence was enriched for genes related to electrochemical balance and transmembrane transport, likely in response to increased selection for dehydration resistance on the hotter slope. Both species shared genomic regions that underwent major selective sweeps, but the overall level of adaptive convergence was low, demonstrating no shortage of alternative genomic solutions to cope with the challenges of the microclimate contrast. Mobile elements were a major source of genetic polymorphism and divergence, affecting all parts of the genome, including coding sequences of mating behavior-related genes.


Assuntos
Comportamento Animal/fisiologia , Drosophila simulans/genética , Genoma/genética , Animais , Biodiversidade , Drosophila melanogaster/genética , Evolução Molecular , Genômica/métodos , Israel , Proteínas de Membrana/genética , Polimorfismo Genético/genética
4.
Artigo em Inglês | MEDLINE | ID: mdl-27860449

RESUMO

Cerium oxide nanoparticles have widespread use in the materials industry, and have recently come into consideration for biomedical use due to their potent regenerative antioxidant properties. Given that the brain is one of the most highly oxidative organs in the body, it is subject to some of the greatest levels of oxidative stress, particularly in neurodegenerative disease. Therefore, cerium oxide nanoparticles are currently being investigated for efficacy in several neurodegenerative disorders and have shown promising levels of neuroprotection. This review discusses the basis for cerium oxide nanoparticle use in neurodegenerative disease and its hypothesized mechanism of action. The review focuses on an up-to-date summary of in vivo work with cerium oxide nanoparticles in animal models of neurodegenerative disease. Additionally, we examine the current state of information regarding biodistribution, toxicity, and safety for cerium oxide nanoparticles at the in vivo level. Finally, we discuss future directions that are necessary if this nanopharmaceutical is to move up from the bench to the bedside. WIREs Nanomed Nanobiotechnol 2017, 9:e1444. doi: 10.1002/wnan.1444 For further resources related to this article, please visit the WIREs website.


Assuntos
Cério/farmacologia , Nanopartículas/química , Doenças Neurodegenerativas/tratamento farmacológico , Neuroproteção , Animais , Antioxidantes/farmacologia , Humanos , Estresse Oxidativo , Distribuição Tecidual
5.
Biomed Sci Instrum ; 49: 312-9, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23686215

RESUMO

Research into the mechanics of blast-induced traumatic brain injury requires a device capable of reproducing pressures of the same magnitude and time scale as a blast wave. A blast simulator based on the exploding bridge wire mechanism was created with these capabilities. Peak blast pressures in the range of 5 – 29 psi were generated with a positive phase duration less than 20 µs. A series of experiments using 0.008 inch diameter wires (10-20 psi) were used to demonstrate the ability of the blast simulator to injure in vitro primary brain cell cultures at 1, 24, and 48 hours following blast. Blast exposure caused a rapid loss of cells which was significant over controls. Propidium iodide uptake indicated limited injury to cellular membranes but the cytoskeletal structure showed signs of degeneration 1 hour following blast. These results indicate that the bridge wire blast simulator can serve as a suitable in vitro model of blast injury.

6.
Int J Toxicol ; 31(3): 238-49, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22674931

RESUMO

This study examined the effects of malathion and lead on transient receptor potential canonical channel TRPC1/TRPC4 channels in rat brain endothelial cells as a mechanism to explain previously noted blood-brain barrier (BBB) permeability induced by these compounds. Lead, malathion, malaoxon and combinations of these were assessed for protein levels and gene expression of TRPC1/C4 at 2, 4, 8, 16, and 24 hours after exposure. Changes in intracellular free calcium dynamics were also assessed. Compounds increased TRPC1 and TRPC4 protein levels as well as gene expression within 4 hours after exposure. Basal levels of intracellular free calcium were also elevated. Increases in gene and protein expression may be associated with an increase in the numbers of TRP channels, and the increases in intracellular calcium may be associated with activation of such channels. Therefore, upregulation and activation of the TRPC1/TRPC4 may be a mechanism by which these neurotoxicants affect BBB permeability.


Assuntos
Células Endoteliais/efeitos dos fármacos , Inseticidas/toxicidade , Malation/análogos & derivados , Compostos Organometálicos/toxicidade , Canais de Cátion TRPC/biossíntese , Animais , Barreira Hematoencefálica/citologia , Cálcio/metabolismo , Linhagem Celular , Células Endoteliais/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Malation/toxicidade , Ratos , Canais de Cátion TRPC/genética
7.
J Parasitol ; 98(6): 1296-9, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22512377

RESUMO

Toxoplasma gondii is an obligate intracellular parasite often found in the brain of humans. Research has shown a correlation between prevalence of antibody titers to T. gondii and psychological illness in humans. Recent studies indicate that individuals seropositive for T. gondii antibodies are more likely to develop psychotic disorders including schizophrenia, which is associated with changes in the dopamine neurotransmitter system. Dopamine in the brain may play a role in proliferation, chemoattraction, infection efficiency, or stage conversion of T. gondii . Because tachyzoites are the first developmental stage to reach the brain, the present study was conducted to determine the effects of dopamine on their development in vitro. In human fibroblast host cells, dopamine was added at either 100 nM or 250 nM to cell culture media, and the numbers of tachyzoites produced at 48 hr were determined and compared to vehicle-treated controls. An increase of tachyzoite numbers and increased destruction in cell monolayer were observed at both concentrations of dopamine. Dopamine used at 250 nM caused a significant (P < 0.05) increase in tachyzoites counts compared to controls. Dopamine antagonists (10 µM) did not significantly alter dopamine-stimulated tachyzoite production in human fibroblasts. In primary neonatal rat astrocyte cell cultures, dopamine (200 µM) significantly (P < 0.05) increased numbers of intracellular tachyzoites after 24 hr. The role that this increase plays in tachyzoite production under the stimulus of dopamine in the modulation of neural infection in humans awaits further studies.


Assuntos
Astrócitos/parasitologia , Dopamina/farmacologia , Fibroblastos/parasitologia , Simpatomiméticos/farmacologia , Toxoplasma/crescimento & desenvolvimento , Animais , Animais Recém-Nascidos , Astrócitos/efeitos dos fármacos , Células Cultivadas , Antagonistas de Dopamina/farmacologia , Fibroblastos/efeitos dos fármacos , Humanos , Ratos , Ratos Sprague-Dawley , Esquizofrenia/complicações , Esquizofrenia/metabolismo , Toxoplasma/efeitos dos fármacos , Toxoplasmose Cerebral/complicações , Toxoplasmose Cerebral/metabolismo , Toxoplasmose Cerebral/psicologia
8.
Infect Disord Drug Targets ; 9(4): 445-52, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19689385

RESUMO

The new ground being broken by the field of nanotechnology provides us with numerous prospects for treatment and prevention of infectious diseases. Recent reports have demonstrated that several types of nanoparticles act as potent free radical scavengers and antioxidants. Specific nanoconstructs are also reported to have anti-inflammatory activities. Given these properties, the potential application of antioxidant nanoparticles for controlling infectious diseases are discussed in this review. Numerous pathogenic agents establish their virulence and pathogenicity by virtue of their ability to produce free radicals and damage the cells of the immune system. For example, Pseudomonas aeruginosa is a bacterium that produces the toxin pyocyanin, which induces cell damage and compromises the immune system through production of reactive oxygen species (ROS). Nanoparticle antioxidants may provide unique opportunities to counteract the pathogenicity of these types of microorganisms and their formation of biofilms, which are also related to oxygen levels and ROS production. The use of nanoparticles may also play a role in controlling conditions such as ventilation associated pneumonia, where high levels of oxygen induces oxidative stress and inhibits respiratory tract immunity. In contrast, nanoparticle antioxidants, by virtue of their anti-inflammatory activity, may blunt a host's normal immune defenses to certain microorganisms. This review will address this emerging double-edged sword for nanomedicine and its potential role in controlling infectious disease and will address future directions for research in this emerging frontier.


Assuntos
Anti-Inflamatórios/farmacologia , Antioxidantes/farmacologia , Doenças Transmissíveis/tratamento farmacológico , Estresse Oxidativo/efeitos dos fármacos , Animais , Anti-Inflamatórios/uso terapêutico , Antioxidantes/metabolismo , Radicais Livres/metabolismo , Humanos , Nanomedicina/métodos , Nanomedicina/tendências , Nanopartículas
9.
Toxicol Appl Pharmacol ; 238(3): 280-8, 2009 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-19379767

RESUMO

The field of nanotechnology is rapidly expanding with the development of novel nanopharmaceuticals that have potential for revolutionizing medical treatment. The rapid pace of expansion in this field has exceeded the pace of pharmacological and toxicological research on the effects of nanoparticles in the biological environment. The development of cadmium-containing nanoparticles, known as quantum dots, show great promise for treatment and diagnosis of cancer and targeted drug delivery, due to their size-tunable fluorescence and ease of functionalization for tissue targeting. However, information on pharmacology and toxicology of quantum dots needs much further development, making it difficult to assess the risks associated with this new nanotechnology. Further, nanotechnology poses yet another risk for toxic cadmium, which will now enter the biological realm in nano-form. In this review, we discuss cadmium-containing quantum dots and their physicochemical properties at the nano-scale. We summarize the existing work on pharmacology and toxicology of cadmium-containing quantum dots and discuss perspectives in their utility in disease treatment. Finally, we identify critical gaps in our knowledge of cadmium quantum dot toxicity, and how these gaps need to be assessed to enable quantum dot nanotechnology to transit safely from bench to bedside.


Assuntos
Cádmio/toxicidade , Poluentes Ambientais/toxicidade , Nanopartículas Metálicas , Nanotecnologia , Pontos Quânticos , Animais , Cádmio/farmacocinética , Cádmio/uso terapêutico , Diagnóstico por Imagem/efeitos adversos , Relação Dose-Resposta a Droga , Humanos , Neoplasias/induzido quimicamente , Tamanho da Partícula , Medição de Risco
10.
Biomed Sci Instrum ; 45: 125-30, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19369751

RESUMO

Traumatic Brain Injury is hypothesized to occur as a function of the strain and strain rate experienced by neural tissues during a traumatic event. In vitro studies of TBI at the cellular level have used a variety of methods to subject neural cell cultures to potentially injurious strains and strain rates. The Advanced Cell Deformation System (ACDS) has been developed which has the ability to independently control strain and strain rate and can strain cell cultures grown on a stretchable membrane from 0.1 to 0.60 at rates up to 25 s-1. The ability to control strain and strain rate independently or to simulate quick repetitive loading was not available in previous devices. Here we present the experiments testing the ability of the ACDS to replicate the results of in vitro experiments of neural cell deformation conducted by earlier researchers. This is a first step toward future experiments which will use the more advanced capabilities of the ACDS.

11.
Biomed Sci Instrum ; 44: 483-8, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-19141962

RESUMO

Traumatic Brain Injury is hypothesized to occur as a function of the strain and strain rate experienced by neural tissues during a traumatic event. In vitro studies of TBI at the cellular level have used a variety of methods to subject neural cell cultures to potentially injurious strains and strain rates. A device used in previous investigations of neural cell injury was limited in its ability to control strain and strain rate independently or simulate quick repetitive loading. Here we present the design of an improved cell injury controller based on an experimental setup previously used. The new device has the ability to independently control strain and strain rate and can strain cell cultures grown on a stretchable membrane from 0.1 to 0.60 at rates up to 25 s-1.

12.
Ann N Y Acad Sci ; 1122: 219-30, 2007 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18077575

RESUMO

In engineering and materials science, nanotechnology has provided many advances that effectively reduce oxidative damage generated by free radical production. Despite such advances, there has been little application to biomedical problems. Increased oxidative stress and free radical production are associated with neurodegenerative conditions, including aging, trauma, Alzheimer's and Parkinson's diseases, and many others. The antioxidant properties of cerium oxide nanoparticles show promise in the treatment of such diseases. Here, we summarize the work on the biological antioxidant actions of cerium oxide nanoparticles in extension of cell and organism longevity, protection against free radical insult, and protection against trauma-induced neuronal damage. We discuss establishment of effective dosing parameters, along with the physicochemical properties that regulate the pharmacological action of these new nanomaterials. Taken together, these studies suggest that nanotechnology can take pharmacological treatment to a new level, with a novel generation of nanopharmaceuticals.


Assuntos
Cério/uso terapêutico , Nanomedicina/métodos , Doenças Neurodegenerativas/terapia , Fármacos Neuroprotetores/uso terapêutico , Animais , Radicais Livres/toxicidade , Humanos
13.
Nanomedicine (Lond) ; 1(4): 399-412, 2006 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-17716143

RESUMO

Nanotechnology has made significant advances in the reduction of free radical damage in the field of materials science. Cross-disciplinary interactions and the application of this technology to biological systems has led to the elucidation of novel nanoparticle antioxidants, which are the subject of this review. Recent reports suggest that cerium oxide and other nanoparticles are potent, and probably regenerative, free radical scavengers in vitro and in vivo. The neuroprotective, longevity-enhancing and anti-inflammatory properties of nanoparticles are summarized and hypotheses regarding their unique mechanism of action are presented. The chemical and physical properties of antioxidant nanoparticles are discussed in an interdisciplinary manner, with emphasis on biological properties and biomedical applications. Additionally, the need for alterations in traditional pharmacological parameters of dose and absorption, distribution, metabolism, and excretion are discussed and future directions necessary for bringing nanoparticle antioxidants into the realm of clinical reality are presented.


Assuntos
Antioxidantes/química , Antioxidantes/uso terapêutico , Desenho de Fármacos , Nanomedicina/métodos , Nanomedicina/tendências , Nanopartículas/química , Nanopartículas/uso terapêutico , Anti-Inflamatórios/química , Anti-Inflamatórios/uso terapêutico
14.
Technol Cancer Res Treat ; 4(6): 651-9, 2005 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-16292885

RESUMO

The field of engineering has made substantial strides in nanotechnology, in the realm of materials science and construction of nanoscale devices. Nanomedicine encompasses application of cutting edge engineered nanostructures to biological systems and development of novel strategies for disease intervention. In the current review, we discuss the pharmacological application of nanoparticles as free radical scavengers and the capacity of nanoparticles to promote cell and organismal longevity.


Assuntos
Senescência Celular , Radicais Livres , Nanoestruturas , Sobrevivência Celular , Sistemas de Liberação de Medicamentos , Desenho de Fármacos , Terapia Genética , Humanos , Neoplasias/diagnóstico , Neoplasias/terapia
15.
J Neurotrauma ; 21(2): 205-16, 2004 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-15000761

RESUMO

We have previously found that in vitro traumatic injury uncouples IP3-mediated intracellular free calcium ([Ca2+]i) signaling in astrocytes (Rzigalinski et al., 1998; Floyd et al., 2001). Since Group I metabotropic glutamate receptors (mGluRs) are coupled to IP3-mediated Ca2+ signaling, we investigated their role in the in vitro strain injury of cultured astrocytes. Astrocytes grown on Silastic membranes were labeled with 3H-myo-inositol and strain (stretch)-injured. Cells injured in the presence of LiCl to prevent inositol phosphate metabolism were acid extracted and inositol phosphates (IPx) isolated using anion exchange columns. Reactive gliosis was assessed as increased glial fibrillary acidic protein immunoreactivity (GFAP-IR). Pre- but not post-injury administration of (RS)-1-aminoindan-15-decarboxylic acid (AIDA) or (S)-4-carboxy-3-hydroxyphenylglycine (S4CH3HPG), both group I mGluR antagonists, attenuated injury-induced increases in IPx. Injury increased GFAP-IR in astrocytes at 24 and 48 h post injury, which was reduced or blocked by AIDA or inhibition of phospholipase C (PLC) with U73122. These findings suggest that strain injury activates Group I mGluRs, causing aberrant IPx production and uncoupling of the PLC signaling pathway. Changes in this signaling pathway may be related to induction of reactive gliosis. Additionally, our results suggest a complex physical coupling between G protein receptor, PLC, and IP3 receptor, in support of the conformational coupling model.


Assuntos
Astrócitos/efeitos dos fármacos , Astrócitos/metabolismo , Gliose/metabolismo , Glicina/análogos & derivados , Fosfatos de Inositol/metabolismo , Receptores de Glutamato Metabotrópico/antagonistas & inibidores , Fosfolipases Tipo C/antagonistas & inibidores , Animais , Astrócitos/citologia , Cálcio/metabolismo , Células Cultivadas , Antagonistas de Aminoácidos Excitatórios/farmacologia , Proteína Glial Fibrilar Ácida/metabolismo , Gliose/tratamento farmacológico , Glicina/farmacologia , Indanos/farmacologia , Fármacos Neuroprotetores/farmacologia , Ratos , Ratos Sprague-Dawley , Estresse Mecânico
16.
J Neurotrauma ; 19(11): 1433-43, 2002 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-12490008

RESUMO

A fundamental mechanism that is believed to contribute to neuronal injury and death following traumatic brain injury (TBI) is a disruption in cellular calcium homeostasis. Of primary importance to these homeostatic mechanisms are intracellular calcium stores located on the endoplasmic reticulum. These intracellular stores play an important role in maintaining normal levels of calcium and calcium-mediated signaling through these stores is critical to several physiological processes in neurons. Using an in vitro model of stretch-induced traumatic injury and fura-2 digital calcium imaging, we investigated alterations in calcium-induced calcium release (CICR) and inositol (1,4,5)-trisphosphate (IP(3))-linked signaling through intracellular calcium stores in populations of cultured rat cortical neurons. Caffeine, which stimulates CICR, produced a rapid elevation of intracellular free calcium ([Ca(2+)](i)) in 70% of uninjured neurons. Fifteen min after injury the population of caffeine-responsive neurons was reduced to 30%. The IP(3)-linked muscarinic acetylcholine receptor agonists, CDD-0097 HCl and McN-A-343, produced elevations in [Ca(2+)](i) in 91% and 70% of uninjured neurons, respectively. Following injury the population of responders was reduced to 19% and 26%, respectively. Differential responses to agonists were also noted after injury, in which the majority of neurons within a given culture well were unresponsive to agonists while others elicited a normal elevation of calcium. These results suggest disruptions in intracellular calcium store-mediated signaling and altered calcium signaling population dynamics following injury. These alterations could affect normal neurotransmission in the brain and may contribute to some of the pathology of TBI.


Assuntos
Lesões Encefálicas/metabolismo , Cafeína/farmacologia , Cálcio/metabolismo , Agonistas Muscarínicos/farmacologia , Neurônios/efeitos dos fármacos , Neurônios/patologia , Animais , Animais Recém-Nascidos , Lesões Encefálicas/patologia , Cálcio/farmacologia , Células Cultivadas , Neuroglia/efeitos dos fármacos , Neuroglia/metabolismo , Neuroglia/patologia , Neurônios/metabolismo , Ratos , Ratos Sprague-Dawley , Receptores Muscarínicos/fisiologia
17.
J Neurotrauma ; 19(12): 1619-29, 2002 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-12542862

RESUMO

In our previous studies, we have shown that in vitro biaxial strain (stretch) injury of neurons in neuronal plus glial cultures increases intracellular free calcium ([Ca(2+)](i)) and decreases mitochondrial membrane potential (deltapsi(m)). The goal of this study was to determine whether strain injury, without the addition of exogenous agents, causes glutamate release, and whether NMDA receptor antagonists affect the post-strain injury rise in [Ca(2+)](i) and decrease in deltapsi(m). [Ca(2+)](i) and deltapsi(m) were measured using the fluorescent indicators fura-2 AM and rhodamine-1,2,3 (rh123). Strain injury of neuronal plus glial cultures caused an immediate 100-200 nM elevation in neuronal [Ca(2+)]i and a decline in neuronal deltapsi(m) by 15 min post-injury. Pretreatment with the NMDA receptor antagonist MK-801 (10 microM) attenuated the [Ca(2+)](i) elevation after mild, but not moderate and severe injury. MK-801 pretreatment reduced the decline in deltapsi(m) after mild and moderate, but not after severe injury. The NMDA receptor antagonist D-2-amino-5-phosphonopentanoic acid (APV; 100 microM) had effects similar to MK-801. Simultaneous measurement of [Ca(2+)](i) and deltapsi(m) demonstrated a significant correlation and a temporal relationship between [Ca(2+)](i) elevation and depression of deltapsi(m). We conclude that NMDA receptor stimulation contributes to some of the changes in [Ca(2+)](i) and deltapsi(m) after less severe strain injury. However, after more pronounced injury other mechanisms appear to be more involved.


Assuntos
Astrócitos/fisiologia , Cálcio/metabolismo , Membranas Intracelulares/metabolismo , Mitocôndrias/fisiologia , Neurônios/fisiologia , Receptores de N-Metil-D-Aspartato/fisiologia , Estresse Mecânico , 2-Amino-5-fosfonovalerato/farmacologia , Animais , Animais Recém-Nascidos , Astrócitos/metabolismo , Carbonil Cianeto p-Trifluormetoxifenil Hidrazona/farmacologia , Células Cultivadas , Técnicas de Cocultura , Maleato de Dizocilpina/farmacologia , Antagonistas de Aminoácidos Excitatórios/farmacologia , Corantes Fluorescentes , Potenciais da Membrana/fisiologia , Neurônios/metabolismo , Ratos , Ratos Sprague-Dawley , Fatores de Tempo
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