This Event is licensed under the Creative Commons BY-SA license. This license allows reusers to distribute, remix, adapt, and build upon the material in any medium or format, so long as attribution is given to the creator. The license allows for commercial use. If you remix, adapt, or build upon the material, you must license the modified material under identical terms.

Event: 1350

Key Event Title

A descriptive phrase which defines a discrete biological change that can be measured. More help

Increased, glutamate

Short name

The KE short name should be a reasonable abbreviation of the KE title and is used in labelling this object throughout the AOP-Wiki. More help

Explore in a Third Party Tool

Biological Context

Structured terms, selected from a drop-down menu, are used to identify the level of biological organization for each KE. More help

Level of Biological Organization
Molecular

Cell term

The location/biological environment in which the event takes place.The biological context describes the location/biological environment in which the event takes place. For molecular/cellular events this would include the cellular context (if known), organ context, and species/life stage/sex for which the event is relevant. For tissue/organ events cellular context is not applicable. For individual/population events, the organ context is not applicable. Further information on Event Components and Biological Context may be viewed on the attached pdf. More help

Cell term
neuron

Organ term

Key Event Components

The KE, as defined by a set structured ontology terms consisting of a biological process, object, and action with each term originating from one of 14 biological ontologies (Ives, et al., 2017; https://aopwiki.org/info_pages/2/info_linked_pages/7#List). Biological process describes dynamics of the underlying biological system (e.g., receptor signalling).Biological process describes dynamics of the underlying biological system (e.g., receptor signaling). The biological object is the subject of the perturbation (e.g., a specific biological receptor that is activated or inhibited). Action represents the direction of perturbation of this system (generally increased or decreased; e.g., ‘decreased’ in the case of a receptor that is inhibited to indicate a decrease in the signaling by that receptor). Note that when editing Event Components, clicking an existing Event Component from the Suggestions menu will autopopulate these fields, along with their source ID and description. To clear any fields before submitting the event component, use the 'Clear process,' 'Clear object,' or 'Clear action' buttons. If a desired term does not exist, a new term request may be made via Term Requests. Event components may not be edited; to edit an event component, remove the existing event component and create a new one using the terms that you wish to add. Further information on Event Components and Biological Context may be viewed on the attached pdf. More help

Process	Object	Action
synaptic transmission, glutamatergic	L-glutamate(1-)	increased

Key Event Overview

AOPs Including This Key Event

All of the AOPs that are linked to this KE will automatically be listed in this subsection. This table can be particularly useful for derivation of AOP networks including the KE.Clicking on the name of the AOP will bring you to the individual page for that AOP. More help

AOP Name	Role of event in AOP	Point of Contact	Author Status
Molecular events lead to epilepsy	KeyEvent	Allie Always (send email)	Open for adoption
presynaptic neuron 1 activation to epilepsy	KeyEvent	Brendan Ferreri-Hanberry (send email)	Open for adoption
AChE Inhibition Leading to Neurodegeneration	KeyEvent	Allie Always (send email)	Under development: Not open for comment. Do not cite
Co-activation of IP3R and RyR to socio-economic burden through lower IQ	KeyEvent	Arthur Author (send email)	Under development: Not open for comment. Do not cite

Taxonomic Applicability

Latin or common names of a species or broader taxonomic grouping (e.g., class, order, family) that help to define the biological applicability domain of the KE.In many cases, individual species identified in these structured fields will be those for which the strongest evidence used in constructing the AOP was available in relation to this KE. More help

Term	Scientific Term	Evidence	Link
zebrafish	Danio rerio	High	NCBI
rat	Rattus norvegicus	High	NCBI

Life Stages

An indication of the the relevant life stage(s) for this KE. More help

Life stage	Evidence
All life stages

Sex Applicability

An indication of the the relevant sex for this KE. More help

Term	Evidence
Unspecific	High

Key Event Description

A description of the biological state being observed or measured, the biological compartment in which it is measured, and its general role in the biology should be provided. More help

Glutamate (Glu) release into the synaptic cleft is primarily caused by excitatory glutamatergic neurons, however there is evidence showing astrocytes releasing glutamate through a calcium-dependent process. A mechanism explaining how astrocytes release glutamate is not well defined, but it could be released through exocytosis(Nedergaard et al. 2002). Glutamate is the main excitatory transmitter in the brain and spinal cord, where it activates both ionotropic and metabotropic receptors. There are 3 main ionotropic receptor classifications, AMPA, Kainate, and NMDA receptors, which are always excitatory (Kandel et al. 2013: 213). Excessive extracellular glutamate release overactivates these signaling pathways, and propagates the excitotoxicity caused by some nerve agents (McDonough and Shih 1997).

How It Is Measured or Detected

A description of the type(s) of measurements that can be employed to evaluate the KE and the relative level of scientific confidence in those measurements.These can range from citation of specific validated test guidelines, citation of specific methods published in the peer reviewed literature, or outlines of a general protocol or approach (e.g., a protein may be measured by ELISA). Do not provide detailed protocols. More help

Glutamate uptake by astrocytes and synaptic cleft concentration can be measured using liquid scintillation spectrometry and radiolabeled glutamate (H³ glutamate) (Lallement et al. 1991). Liquid scintillation spectrometry counts the activity of a radioactive sample by mixing the glutamate with a liquid scintillator (a material that fluorescens) and count photon emissions.
Another mechanism to measure the glutamate concentration in the synaptic cleft is by microdialysis sampling. This mechanism is inexpensive and easy to use. When microdialysis is paired with other analytical methods such as High-Pressure Liquid Chromatography (HPLC), there is a higher instrumental selectivity and sensitivity (Watson et al. 2006).

Domain of Applicability

A description of the scientific basis for the indicated domains of applicability and the WoE calls (if provided). More help

Taxa:

Zebrafish neurotransmitter systems, including glutamate, are being used more for investigating chemical toxicity (Horzmann and Freeman 2016). Some cited sources above have data from rat experiments.

Life Stage:

Glutamate is functional throughout all life stages. Liu et al. (1996) suggests that immature rat brains show less glutamate-induced neurotoxicity than adult brains.

Sex:

Glutamate and glutamate receptors have been studied in both males and females, with similar functionality (Jafarian et al. 2019).

References

List of the literature that was cited for this KE description. More help

Horzmann, K. A. and J. L. Freeman (2016), "Zebrafish get connected: investigating neurotransmission targets and alterations in chemical toxicity.” Toxics 4(3).

Jafarian, M., S. M. Modarres Mousavi, F. Alipour, H. Aligholi, F. Noorbakhsh, M. Ghadipasha, J. Gharehdaghi, C. Kellinghaus, S. Kovac, M. Khaleghi Ghadiri, S. G. Meuth, E. J. Speckmann, W. Stummer and A. Gorji (2019), "Cell injury and receptor expression in the epileptic human amygdala.” Neurobiology of Disease 124. DOI: 10.1016/j.nbd.2018.12.017.

Kandel, E., J. Schwartz, T. Jessell, S. Siegelbaum and A. J. Hudspeth (2013), Principles of Neural Science, Fifth Edition. Blacklick, United States, McGraw-Hill Publishing.

Lallement, G., P. Carpentier, A. Collet, I. Pernot-Marino, D. Baubichon and G. Blanchet (1991), "Effects of soman-induced seizures on different extracellular amino acid levels and on glutamate uptake in rat hippocampus.” Brain Research 563(1-2). DOI: 10.1016/0006-8993(91)91539-D.

Liu, Z., C. E. Stafstrom, M. Sarkisian, P. Tandon, Y. Yang, A. Hori and G. L. Holmes (1996), "Age-dependent effects of glutamate toxicity in the hippocampus.” Brain Res Dev Brain Res 97(2).

McDonough, J. H., Jr. and T. M. Shih (1997), "Neuropharmacological mechanisms of nerve agent-induced seizure and neuropathology.” Neurosci Biobehav Rev 21(5).

Nedergaard, M., T. Takano and A. J. Hansen (2002), "Beyond the role of glutamate as a neurotransmitter.” Nature Reviews Neuroscience 3(9). DOI: 10.1038/nrn916.

Watson, C. J., B. J. Venton and R. T. Kennedy (2006), "In vivo measurements of neurotransmitters by microdialysis sampling.” Analytical Chemistry 78(5).