Anesthetics and Mild Hypothermia Similarly Prevent Hippocampal Neuron Death in an In Vitro Model of Cerebral Ischemia

2000 ◽  
Vol 92 (5) ◽  
pp. 1343-1349 ◽  
Author(s):  
Robert Popovic ◽  
Richard Liniger ◽  
Philip E. Bickler
Keyword(s):  
Cerebral Ischemia ◽  
Mild Hypothermia ◽  
Cell Damage ◽  
Hippocampal Slices ◽  
Cell Loss ◽  
Glutamate Excitotoxicity ◽  
Neuron Death ◽  
In Vitro Ischemia ◽  
Aspartate Receptor

Background General anesthetics reduce neuron loss following focal cerebral ischemia in rodents. The relative efficacy of this action among different anesthetics clinically used for neuroprotection is uncertain. In addition, it remains unclear how anesthetics compare to neuroprotection afforded by mild hypothermia. This study was performed to evaluate the comparative effects of isoflurane, sodium pentothal, and mild hypothermia in a hippocampal slice model of cerebral ischemia and to determine if the mechanism of neuroprotection of isoflurane involves inhibition of glutamate excitotoxicity. Methods Survival and morphology of CA1, CA3, and dentate gyrus neurons in rat hippocampal slices were examined after 10 or 20 min of combined oxygen-glucose deprivation (in vitro ischemia) followed by a 5-h recovery period. Results 10 or 20 min in vitro ischemia at 37 degrees C killed 35-40% of neurons in CA1 (P < 0.001), 6% in CA3 (not significant) and 18% in dentate (P < 0.05). Isoflurane (0.7 and 2.0%, approximately 0.45 and 1.5 minimum alveolar concentration), pentothal (50 microm, approximately 1 minimum alveolar concentration equivalent) and mild hypothermia (34 degrees C) all reduced CA1 cell loss and morphologic damage to similar degrees in 10- and 20-min periods of ischemia (P < 0.001). The noncompetitive N-methyl-D-aspartate antagonist MK-801 prevented cell damage, showing that N-methyl-D-aspartate receptor activation is an important mechanism of injury in this model. Glutamate (1 mm) produced cell loss similar to in vitro ischemia. Isoflurane (2%) prevented cell damage from glutamate exposure. Conclusions In hippocampal slices, neuron death from simulated ischemia was predominately due to activation of glutamate receptors. Isoflurane, sodium pentothal, an N-methyl-D-aspartate receptor antagonist, and mild hypothermia prevented cell death to similar degrees. For isoflurane, the mechanism appears to involve attenuation of glutamate excitotoxicity.

scholarly journals Antioxidant Activities of Solanum Nigrum L. Leaf Extracts Determined in in vitro Cellular Models

Foods ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 63 ◽  
Author(s):  
Agata Campisi ◽  
Rosaria Acquaviva ◽  
Giuseppina Raciti ◽  
Anna Duro ◽  
Milena Rizzo ◽  
...  
Keyword(s):  
Antioxidant Activities ◽  
Cell Damage ◽  
Glutamate Uptake ◽  
Primary Cultures ◽  
Solanum Nigrum ◽  
Oxidative Status ◽  
Glutamate Excitotoxicity ◽  
Cellular Models ◽  
Solanum Nigrum L

Several medicinal foods abound in traditional medicine with antioxidant potentials that could be of importance for the management of several diseases but with little or no scientific justification to substantiate their use. Thus, the objective of this study was the assessment of the antioxidant effect of two leave extracts of Solanum nigrum L. (SN), which is a medicinal plant member of the Solanaceae family, mainly used for soup preparation in different parts of the world. Then methanolic/water (80:20) (SN1) and water (SN2) leaves extracts were prepared. The total polyphenolic content and the concentration of phenolic acids and flavones compounds were determined. In order to verify whether examined extracts were able to restore the oxidative status, modified by glutamate in primary cultures of astrocytes, the study evaluated the glutathione levels, the intracellular oxidative stress, and the cytotoxicity of SN1 and SN2 extracts. Both extracts were able to quench the radical in an in vitro free cellular system and restore the oxidative status in in vitro primary cultures of rat astroglial cells exposed to glutamate. These extracts prevented the increase in glutamate uptake and inhibited glutamate excitotoxicity, which leads to cell damage and shows a notable antioxidant property.

Extrusion of Intracellular Calcium Ion After In Vitro Ischemia in the Rat Hippocampal CA1 Region

2002 ◽  
Vol 88 (2) ◽  
pp. 879-887 ◽  
Author(s):  
E. Tanaka ◽  
H. Uchikado ◽  
S. Niiyama ◽  
K. Uematsu ◽  
H. Higashi
Keyword(s):  
Glial Cells ◽  
Hippocampal Slices ◽  
Negative Potential ◽  
Acetoxymethyl Ester ◽  
Rapid Reduction ◽  
In Vitro Ischemia ◽  
Ca1 Region ◽  
Dc Potential ◽  
Slow Negative Potential

Simultaneous recordings of intracellular Ca2+([Ca2+]i) signal and extracellular DC potential were obtained from the CA1 region in 1-[6-amino-2-(5-carboxy-2-oxazolyl)-5-benzofuranyloxy]-2-(2-amino-5-methylphenoxy)-ethane- N, N, N′, N′-tetraacetic acid penta-acetoxymethyl ester (Fura-2/AM)-loaded rat hippocampal slices. Superfusion with oxygen- and glucose-deprived medium (in vitro ischemia) for 5–6 min produced a rapid rise of the [Ca2+]i level in the stratum radiatum (rising phase of the [Ca2+]i signal), which occurred simultaneously with a rapid negative DC potential (rapid negative potential). When oxygen and glucose were reintroduced, the increased [Ca2+]i signal diminished rapidly (falling phase of the [Ca2+]i signal) during the generation of a slow negative DC potential (slow negative potential), which occurred within 1 min from the onset of the reintroduction. Thereafter, the [Ca2+]i signal partially and the slow negative potential completely returned to the preexposure level approximately 6 min after the reintroduction. The changes in [Ca2+]i signal during and after in vitro ischemia were very similar to the changes in the membrane potential of glial cells. The rising and falling phases of [Ca2+]i signal corresponded to the rapid depolarization and a depolarizing hump, respectively, in the repolarizing phase of glial cells. A prolonged application of in vitro ischemia or a reintroduction of either glucose or oxygen suppressed the falling phase after ischemic exposure. The application of ouabain (30 μM) generated both a rapid negative potential and a rapid elevation of [Ca2+]i, but no slow negative potential or rapid reduction in [Ca2+]i were observed. When oxygen and glucose were reintroduced to slices in the Na+-free or ouabain- or Ni2+-containing medium, the falling phase was suppressed. The falling phase was significantly accelerated in Ca2+- and Mg2+-free with EGTA-containing medium. In contrast, the falling phase was significantly slower in the Ca2+-free with high Mg2+- and EGTA-containing medium. The falling phase of the [Ca2+]isignal after ischemic exposure is thus considered to be primarily dependent on the reactivation of Na+, K+-ATPases, while the extrusion of cytosolic Ca2+ via the forward-mode operation of Na+/Ca2+ exchangers in glial cells is thought to be directly involved in the rapid reduction of [Ca2+]i after ischemic exposure.

Origin of intracellular Ca2+ elevation induced by in vitro ischemia-like condition in hippocampal slices

1993 ◽  
Vol 601 (1-2) ◽  
pp. 103-110 ◽  
Author(s):  
Akira Mitani ◽  
Hisato Yanase ◽  
Kimiko Sakai ◽  
Youseke Wake ◽  
Kiyoshi Kataoka
Keyword(s):  
Hippocampal Slices ◽  
In Vitro Ischemia

Extracellular Magnesium Ion Modifies the Actions of Volatile Anesthetics in Area CA1 of Rat Hippocampus In Vitro 

2002 ◽  
Vol 96 (3) ◽  
pp. 681-687 ◽  
Author(s):  
Rika Sasaki ◽  
Koki Hirota ◽  
Sheldon H. Roth ◽  
Mitsuaki Yamazaki
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Hippocampal Slices ◽  
Volatile Anesthetics ◽  
Population Spike ◽  
Magnesium Ion ◽  
Excitatory Postsynaptic Potential ◽  
Aspartate Receptor ◽  
Postsynaptic Potential

Background Magnesium ion (Mg2+) is involved in important processes as modulation of ion channels, receptors, neurotransmitter release, and cell excitability in the central nervous system. Although extracellular Mg2+ concentration ([Mg2+]o) can be altered during general anesthesia, there has been no evidence for [Mg2+]o-dependent modification of anesthetic actions on neural excitability in central nervous system preparations. The purpose of current study was to determine whether the effects of volatile anesthetics are [Mg2+]o-dependent in mammalian central nervous system. Methods Extracellular electrophysiologic recordings from CA1 neurons in rat hippocampal slices were used to investigate the effects of [Mg2+]o and anesthetics on population spike amplitude and excitatory postsynaptic potential slope. Results The depression of population spike amplitudes and excitatory postsynaptic potential slopes by volatile anesthetics were significantly dependent on [Mg2+]o. The effects were attenuated in the presence of a constant [Mg2+]o/extracellular Ca2+ concentration ratio. However, neither N-methyl-d-aspartate receptor antagonists nor a non-N-methyl-d-aspartate receptor antagonist altered the [Mg2+]o-dependent anesthetic-induced depression of population spikes. Volatile anesthetics produced minimal effects on input-output (excitatory postsynaptic potential-population spike) relations or the threshold for population spike generation. The effects were not modified by changes in [Mg2+]o. In addition, the population spike amplitudes, elicited via antidromic (nonsynaptic) stimulation, were not influenced by [Mg2+]o in the presence of volatile anesthetics. Conclusions These results provide support that alteration of [Mg2+]o modifies the actions of volatile anesthetics on synaptic transmission and that the effects could be, at least in part, a result of presynaptic Ca2+ channel-related mechanisms.

scholarly journals Neuroprotective Effect of Metaplexis japonica against in vitro Ischemia Model

2019 ◽  
Vol 3 (1) ◽  
pp. 51-55 ◽  
Author(s):  
Nirmala Jamarkattel-Pandit ◽  
Hocheol Kim
Keyword(s):  
Cell Damage ◽  
Neuroprotective Effect ◽  
Ethanol Extract ◽  
Glucose Deprivation ◽  
Ethyl Acetate Fraction ◽  
Perennial Herb ◽  
Oxygen Glucose Deprivation ◽  
In Vitro Ischemia ◽  
Ht22 Cell

Metaplexis japonica (Apocynaceae) is a perennial herb, extensively used in traditional medicinal system for various diseases. The purpose of the study was to evaluate the protective effect of M. japonica against in vitro ischemia. In the present study, 70% ethanol extract of M. japonica was fractionated with different polarity solvents. For in vitro ischemia, oxygen-glucose deprivation followed by reoxygenation (OGD-R) in cells was used to investigate the effects of M. japonica and its fractions. For oxidative stress model, Hydrogen peroxide (H2 O2 ) induced cell death was studied in HT22 cell line. M. japonica and its fractions significantly reduced the HT22 cell damage, which was induced by 4 hrs of OGD followed by 24 hrs of reoxygenation and 24 hrs of H2 O2, respectively. The effectiveness of ethyl acetate fraction was higher than other fractions/crude extract. Our results suggest that M. japonica could be a neuroprotective agent for the treatment of stroke. Key words: Metaplexis japonica, Stroke, Oxygen-glucose deprivation, Neuroprotection

scholarly journals Anesthetic Protection of Neurons Injured by Hypothermia and Rewarming

2012 ◽  
Vol 117 (2) ◽  
pp. 280-292 ◽  
Author(s):  
Philip E. Bickler ◽  
Daniel E. Warren ◽  
John P. Clark ◽  
Pablo Gabatto ◽  
Maren Gregersen ◽  
...  
Keyword(s):  
Cell Death ◽  
Hippocampal Neurons ◽  
Mild Hypothermia ◽  
Culture Media ◽  
Glutamate Excitotoxicity ◽  
Cell Swelling ◽  
Profound Hypothermia ◽  
Anesthetic Agents ◽  
Aspartate Receptor ◽  
Hypoxia Ischemia

Background Mild hypothermia is neuroprotective after cerebral ischemia but surgery involving profound hypothermia (PH, temperature less than 18°C) is associated with neurologic complications. Rewarming (RW) from PH injures hippocampal neurons by glutamate excitotoxicity, N-methyl-D-aspartate receptors, and intracellular calcium. Because neurons are protected from hypoxia-ischemia by anesthetic agents that inhibit N-methyl-D-aspartic acid receptors, we tested whether anesthetics protect neurons from damage caused by PH/RW. Methods Organotypic cultures of rat hippocampus were used to model PH/RW injury, with hypothermia at 4°C followed by RW to 37°C and assessment of cell death 1 or 24 h later. Cell death and intracellular Ca were assessed with fluorescent dye imaging and histology. Anesthetic agents were present in the culture media during PH and RW or only RW. Results Injury to hippocampal CA1, CA3, and dentate neurons after PH and RW involved cell swelling, cell rupture, and adenosine triphosphate (ATP) loss; this injury was similar for 4 through 10 h of PH. Isoflurane (1% and 2%), sevoflurane (3%) and xenon (60%) reduced cell loss but propofol (3 μM) and pentobarbital (100 μM) did not. Isoflurane protection involved reduction in N-methyl-D-aspartate receptor-mediated Ca influx during RW but did not involve γ-amino butyric acid receptors or KATP channels. However, cell death increased over the next day. Conclusion Anesthetic protection of neurons rewarmed from 4°C involves suppression of N-methyl-D-aspartate receptor-mediated Ca overload in neurons undergoing ATP loss and excitotoxicity. Unlike during hypoxia/ischemia, anesthetic agents acting predominantly on γ-aminobutyric acid receptors do not protect against PH/RW. The durability of anesthetic protection against cold injury may be limited.

scholarly journals Targeting CDK5 in Astrocytes Promotes Calcium Homeostasis Under Excitotoxic Conditions

2021 ◽  
Vol 15 ◽  
Author(s):  
Luisa Fernanda Toro-Fernández ◽  
Juan Camilo Zuluaga-Monares ◽  
Ana María Saldarriaga-Cartagena ◽  
Gloria Patricia Cardona-Gómez ◽  
Rafael Posada-Duque
Keyword(s):  
Calcium Homeostasis ◽  
Calcium Influx ◽  
Ex Vivo ◽  
Hippocampal Slices ◽  
Glutamate Excitotoxicity ◽  
Neural Cells ◽  
Neuroprotective Effects ◽  
Hippocampal Area ◽  
Therapy Target

Glutamate excitotoxicity triggers overactivation of CDK5 and increases calcium influx in neural cells, which promotes dendritic retraction, spine loss, increased mitochondrial calcium from the endoplasmic reticulum, and neuronal death. Our previous studies showed that CDK5 knockdown (KD) in astrocytes improves neurovascular integrity and cognitive functions and exerts neuroprotective effects. However, how CDK5-targeted astrocytes affect calcium regulation and whether this phenomenon is associated with changes in neuronal plasticity have not yet been analyzed. In this study, CDK5 KD astrocytes transplanted in CA3 remained at the injection site without proliferation, regulated calcium in the CA1 hippocampal region after excitotoxicity by glutamate in ex vivo hippocampal slices, improving synapsin and PSD95 clustering. These CDK5 KD astrocytes induced astrocyte stellation and neuroprotection after excitotoxicity induced by glutamate in vitro. Also, these effects were supported by CDK5 inhibition (CDK5i) in vitro through intracellular stabilization of calcium levels in astrocytes. Additionally, these cells in cocultures restored calcium homeostasis in neurons, redistributing calcium from somas to dendrites, accompanied by dendrite branching, higher dendritic spines and synapsin-PSD95 clustering. In summary, induction of calcium homeostasis at the CA1 hippocampal area by CDK5 KD astrocytes transplanted in the CA3 area highlights the role of astrocytes as a cell therapy target due to CDK5-KD astrocyte-mediated synaptic clustering, calcium spreading regulation between both areas, and recovery of the intracellular astrocyte-neuron calcium imbalance and plasticity impairment generated by glutamate excitotoxicity.

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