6‐Hydroxykynurenic acid and kynurenic acid differently antagonise AMPA and NMDA receptors in hippocampal neurones

Weber, Marco; Dietrich, Dirk; Gräsel, Ines; Reuter, G.; Seifert, Gerald; Steinhäuser, Christian

doi:10.1046/j.1471-4159.2001.00340.x

Cited by 38 publications

(22 citation statements)

References 30 publications

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“…7) Some constituents of EGBL are reported to suppress the response mediated by NMDA glutamate receptor. 13,14) Furthermore, in present study, EGBL is shown to exert an inhibitory action on non-NMDA glutamate receptor. Some neurodegenerative diseases are resulted from cell death induced by glutamate excitotoxicity and oxidative stress.…”

Section: Discussionsupporting

confidence: 57%

“…7,11,12) EGBL and its constituents inhibit the response mediated by activation of NMDA receptor. 13,14) However, there is limited information concerning the effect of EGBL on response induced by activation of non-NMDA glutamate receptor. Kainate, an agonist for non-NMDA glutamate receptor, increases [Ca 2ϩ ]i in neurons via activations of non-NMDA glutamate receptor and voltage-dependent Ca 2ϩ channel.…”

Section: )mentioning

confidence: 99%

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Extract of Ginkgo biloba Leaves Attenuates Kainate-Induced Increase in Intracellular Ca2+ Concentration of Rat Cerebellar Granule Neurons

Kanada

Nishimura

Yamaguchi

et al. 2005

Biological & Pharmaceutical Bulletin

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The idea that an excessive release of glutamate mediates neuronal cell death was proposed, as the excitotoxicity hypothesis, by Olney and de-Gubareff.1) Glutamate activates two types of its receptor, N-methyl-D-aspartate (NMDA) type and non-NMDA one.2) Excessive activation of glutamate receptors, resulting in increase in intracellular Ca 2ϩ concentration ([Ca 2ϩ ]i) and generation of reactive oxygen species (ROS), is involved in neuronal disorder and degeneration. 3)Both phenomena induced by glutamate are related to cell injury and death. 4,5) In fact, antagonists for NMDA and non-NMDA glutamate receptors are proven to possess neuroprotective action. [6][7][8] Extract of Ginkgo biloba leaves (EGBL) is expected to treat patients with some neuronal disorders such as dementia and Alzheimer's disease. 9,10) The extract exerts protective action (or antioxidant action) on neurons suffering from oxidative stress induced by hydrogen peroxide, one of ROS, and by overload of intracellular Ca 2ϩ . 7,11,12) EGBL and its constituents inhibit the response mediated by activation of NMDA receptor. 13,14) However, there is limited information concerning the effect of EGBL on response induced by activation of non-NMDA glutamate receptor. Kainate, an agonist for non-NMDA glutamate receptor, increases [Ca 2ϩ ]i in neurons via activations of non-NMDA glutamate receptor and voltage-dependent Ca 2ϩ channel. 15) Therefore, in order to elucidate one of mechanisms for neuroprotective action of EGBL, we examined the effect of EGBL on kainate-induced increase in [Ca 2ϩ ]i in rat brain neurons using a laser microscope with fluorescent Ca 2ϩ -indicator. MATERIALS AND METHODS MaterialsExtract of Ginkgo biloba leaves (EGBL) was obtained from Icho-Ha Sangyo Co., Ltd., Ibaraki, Japan. EGBL was initially dissolved in 50% ethanol. EGBL solution (1-30 mg/ml) was added to bathing solution to achieve appropriate concentrations (1-30 mg/ml). Ethanol as a solvent at 0.05% did not affect any fluorescence measurements from cells. Other chemical reagents except for fluorescent probes were purchased from Sigma Chemical Co. (St. Louis, MO, U.S.A.) unless otherwise mentioned.Cell Preparation Experimental method for dissociation of rat cerebellar neurons was similar to those described in previous studies. 16,17) In brief, the slices of cerebellum dissected from 10-to 16-d-old Wistar strain rats were treated with 1000 protease units/ml dispase (Godo Shusei, Tokyo, Japan) in Tyrode's solution for 50-60 min at a temperature of 32-34°C. After enzymatic treatment, cerebellar neurons were dispersed by triturating in Tyrode's solution. Since the majority of neurons were characterized by small size and spherical shape under microscopic observation, they were ascertained as cerebellar granule cells. These cells responded to kainate, resulting in an increase in [Ca 2ϩ ]i.15) The cells were placed on culture dishes and incubated at 35-36°C in Tyrode's solution for 50-60 min before use. The application of chemicals to neurons was performed by a Y-tube...

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Section: Discussionsupporting

confidence: 57%

Section: )mentioning

confidence: 99%

Extract of Ginkgo biloba Leaves Attenuates Kainate-Induced Increase in Intracellular Ca2+ Concentration of Rat Cerebellar Granule Neurons

Kanada

Nishimura

Yamaguchi

et al. 2005

Biological & Pharmaceutical Bulletin

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“…Epigenetic effects of Ginkgo administration with respect to the AMPA receptor [8] may very well represent one of the mechanisms of its action. On the other side, 6-hydroxykynurenic acid, one of the possible active ingredients of Ginkgo, developed an antagonistic action on AMPA-mediated channel activity using a patch clamp design in the hippocampus in vitro [9]. So for Ginkgo extracts Ph.…”

Section: Discussionmentioning

confidence: 99%

<i>Ex Vivo</i> Characterization of the Action of Sideritis Extract Using Electrical Activity in the Rat Hippocampus Slice Preparation

Dimpfel¹,

Schombert²,

Feistel³

2016

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A hydroethanolic extract (20% V/V) from Herba Sideritis scardica has been recognized to positively influence cognition. The present investigation aimed at the question if this extract would be able to modify intra-hippocampal communication after oral administration of 100 mg/kg daily for one week. The glutamatergic synapse between Schaffer Collaterals and pyramidal cells can be tested by electric stimulation using single pulses or theta burst stimulation. The resulting population spike is modulated by compounds acting at the central nervous system or other preparations directly or as ex vivo approach. In this case the effect of the special extract was tested in vitro the next day after repetitive in vivo administration. Conventional recording technique in the in vitro hippocampus slice revealed an increase of the population spike in the presence of single stimuli and theta burst stimuli resulting in increased long-term potentiation. This effect was tried to modulate by several glutamate receptor antagonists, among them compounds targeting at the ionic NMDA receptor (CGS19755), AMPA receptor (NBQX), Kainate receptor (UBP301) and targeting at three metabotropic glutamate receptors (mGluR I (YM298198), mGluRII ((RS)-APICA)) and mGluRIII (MSOP). Only NBQX was able to prevent the action of the Sideritis scardica extract. Since the AMPA receptor has been related to cognition in several reports in the literature, it is concluded from this result that the positive action of Sideritis scardica extract on brain function involves a modulation of AMPA receptor dependent neurotransmission.

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“…Hippocampal cells. Cells were acutely isolated as described (34,35). Briefly, Tg(hGFAP͞EGFP) mice (36) from postnatal days 25-30 were decapitated, and their brains were dissected and cut into 300-m-thick slices in frontal orientation by using a vibratome (HM 650V; Microm International, Walldorf, Germany).…”

Section: Methodsmentioning

confidence: 99%

Viscoelastic properties of individual glial cells and neurons in the CNS

Franze

Seifert

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

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496

438

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One hundred fifty years ago glial cells were discovered as a second, non-neuronal, cell type in the central nervous system. To ascribe a function to these new, enigmatic cells, it was suggested that they either glue the neurons together (the Greek word ''␥␣'' means ''glue'') or provide a robust scaffold for them (''support cells''). Although both speculations are still widely accepted, they would actually require quite different mechanical cell properties, and neither one has ever been confirmed experimentally. We investigated the biomechanics of CNS tissue and acutely isolated individual neurons and glial cells from mammalian brain (hippocampus) and retina. Scanning force microscopy, bulk rheology, and optically induced deformation were used to determine their viscoelastic characteristics. We found that (i) in all CNS cells the elastic behavior dominates over the viscous behavior, (ii) in distinct cell compartments, such as soma and cell processes, the mechanical properties differ, most likely because of the unequal local distribution of cell organelles, (iii) in comparison to most other eukaryotic cells, both neurons and glial cells are very soft (''rubber elastic''), and (iv) intriguingly, glial cells are even softer than their neighboring neurons. Our results indicate that glial cells can neither serve as structural support cells (as they are too soft) nor as glue (because restoring forces are dominant) for neurons. Nevertheless, from a structural perspective they might act as soft, compliant embedding for neurons, protecting them in case of mechanical trauma, and also as a soft substrate required for neurite growth and facilitating neuronal plasticity.biomechanics ͉ elasticity ͉ viscosity ͉ retina ͉ hippocampus

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6‐Hydroxykynurenic acid and kynurenic acid differently antagonise AMPA and NMDA receptors in hippocampal neurones

Cited by 38 publications

References 30 publications

Extract of Ginkgo biloba Leaves Attenuates Kainate-Induced Increase in Intracellular Ca2+ Concentration of Rat Cerebellar Granule Neurons

Extract of Ginkgo biloba Leaves Attenuates Kainate-Induced Increase in Intracellular Ca2+ Concentration of Rat Cerebellar Granule Neurons

<i>Ex Vivo</i> Characterization of the Action of Sideritis Extract Using Electrical Activity in the Rat Hippocampus Slice Preparation

Viscoelastic properties of individual glial cells and neurons in the CNS

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6‐Hydroxykynurenic acid and kynurenic acid differently antagonise AMPA and NMDA receptors in hippocampal neurones

Cited by 38 publications

References 30 publications

Extract of Ginkgo biloba Leaves Attenuates Kainate-Induced Increase in Intracellular Ca2+ Concentration of Rat Cerebellar Granule Neurons

Extract of Ginkgo biloba Leaves Attenuates Kainate-Induced Increase in Intracellular Ca2+ Concentration of Rat Cerebellar Granule Neurons

&lt;i&gt;Ex Vivo&lt;/i&gt; Characterization of the Action of Sideritis Extract Using Electrical Activity in the Rat Hippocampus Slice Preparation

Viscoelastic properties of individual glial cells and neurons in the CNS

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Product

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<i>Ex Vivo</i> Characterization of the Action of Sideritis Extract Using Electrical Activity in the Rat Hippocampus Slice Preparation