Voltage-dependent block by Mg2+ of NMDA responses in spinal cord neurones
- 1 May 1984
- journal article
- Published by Springer Science and Business Media LLC in Nature
- Vol. 309 (5965), 261-263
- https://doi.org/10.1038/309261a0
Abstract
Acidic amino acids are putative excitatory synaptic transmitters, the ionic mechanism of which is not well understood. Recent studies with selective agonists and antagonists suggest that neurones of the mammalian central nervous system possess several different receptors for acidic amino acids, which in turn are coupled to separate conductance mechanisms. N-methyl-D-aspartic acid (NMDA) is a selective agonist for one of these receptors. The excitatory action of amino acids acting at NMDA receptors is remarkably sensitive to the membrane potential and it has been suggested that the NMDA receptor is coupled to a voltage-sensitive conductance. Recently, patch-clamp experiments have shown the voltage-dependent block by Mg2+ of current flow through ion channels activated by L-glutamate. We now show using voltage-clamp experiments on mouse spinal cord neurones that the voltage-sensitivity of NMDA action is greatly reduced on the withdrawal of physiological concentrations (approximately 1 mM) of Mg2+ from the extracellular fluid. This provides further evidence that Mg2+ blocks inward current flow through ion channels linked to NMDA receptors.Keywords
This publication has 15 references indexed in Scilit:
- Magnesium gates glutamate-activated channels in mouse central neuronesNature, 1984
- A voltage‐clamp analysis of inward (anomalous) rectification in mouse spinal sensory ganglion neurones.The Journal of Physiology, 1983
- Multiple actions of N-methyl-d-aspartate on cat neocortical neurons in vitroBrain Research, 1983
- L-aspartic acid induces a region of negative slope conductance in the current-voltage relationship of cultured spinal cord neuronsBrain Research, 1982
- The effects of L-glutamate and its analogues upon the membrane conductance of central murine neurones in cultureCanadian Journal of Physiology and Pharmacology, 1982
- Block of acetylcholine-activated ion channels by an uncharged local anaestheticNature, 1981
- Voltage-dependent caesium blockade of a cation channel from fragmented sarcoplasmic reticulumNature, 1979
- Local anaesthetics transiently block currents through single acetylcholine‐receptor channels.The Journal of Physiology, 1978
- The excitant amino acids glutamic and aspartic acid as transmitter candidates in the vertebrate central nervous systemProgress in Neurobiology, 1978