Magnesium gates glutamate-activated channels in mouse central neurones

@article{Nowak1984MagnesiumGG,
  title={Magnesium gates glutamate-activated channels in mouse central neurones},
  author={Linda M. Nowak and Piotr Bregestovski and Philippe Ascher and Alain Herbet and Alain Prochiantz},
  journal={Nature},
  year={1984},
  volume={307},
  pages={462-465}
}
The responses of vertebrate neurones to glutamate involve at least three receptor types1. One of these, the NMDA receptor (so called because of its specific activation by N-methyl-D-aspartate), induces responses presenting a peculiar voltage sensitivity2–6. Above resting potential, the current induced by a given dose of glutamate (or NMDA) increases when the cell is depolarized4–6. This is contrary to what is observed at classical excitatory synapses, and recalls the properties of ‘regenerative… 

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References

SHOWING 1-10 OF 18 REFERENCES

Selective depression of excitatory amino acid induced depolarizations by magnesium ions in isolated spinal cord preparations.

TLDR
From the similarity in action between Mg2+ and the D‐alpha‐aminoadipate group of NMDA antagonists, it is suggested that the central depressant action of low concentrations of Mg1+ involves predominantly a postsynaptically mediated interference with the action of an excitatory amino acid transmitter.

N-methyl-D-aspartate-type receptors mediate striatal 3H-acetylcholine release evoked by excitatory amino acids

TLDR
Investigating the effects of specific excitatory amino acid receptor agonists and antagonists on the release of 3H-acetylcholine from slices of the rat corpus striatum finds that excitatories amino acid analogues evoke a tetrodotoxin-sensitive release from rat striatal slices superfused in Mg2+-free medium, NMDA and ibotenate being the most potent and kainate and quisqualate the least potent.

The actions of excitatory amino acids on motoneurones in the feline spinal cord.

TLDR
The results for the mechanism of excitatory transmission is discussed and it is concluded that the DLH response is probably mediated via a decrease in K+ conductance and that the availability of this conductance channel is potential dependent.

Permeability of the post‐synaptic membrane of an excitatory glutamate synapse to sodium and potassium.

  • R. Anwyl
  • Biology
    The Journal of physiology
  • 1977
TLDR
It is proposed that the outward K current is dependent upon the inward Na current, and that the increase in K permeability is abolished in zero external Na.

Interaction of Tetraethylammonium Ion Derivatives with the Potassium Channels of Giant Axons

TLDR
A number of compounds related to TEA+ (tetraethylammoniumion) were injected into squid axons and their effects on g K (the potassium conductance) were determined, suggesting that K+ ions traverse the membrane by way of pores, and they cannot be explained by the usual type of carrier model.

Local anaesthetics transiently block currents through single acetylcholine‐receptor channels.

TLDR
It is concluded that drug molecules reversibly block open end‐plate channels and that the flickering within a burst represents this fast, repeatedly occurring reaction.

L‐glutamate as an excitatory transmitter at the Drosophila larval neuromuscular junction.

TLDR
It is concluded that L‐glutamate is, or is an agonist of, the excitatory transmitter at certain Drosophila larval neuromuscular junctions.

The mode of action of antagonists of the excitatory response to acetylcholine in Aplysia neurones.

TLDR
The mode of action of various antagonists of acetylcholine (ACh) excitatory effects on Aplysia neurones was studied under voltage clamp, supporting the hypothesis that the binding site of the antagonists is linked to the ionic channel.