The postexcitatory effects of acidic amino acids on spinal neurones

1981 ◽  
Vol 59 (3) ◽  
pp. 239-243 ◽  
Author(s):  
H. McLennan ◽  
Jin-Rong Liu
Keyword(s):  
Amino Acids ◽  
Spinal Cord ◽  
Excitatory Amino Acids ◽  
Aminobutyric Acid ◽  
Renshaw Cells ◽  
Acidic Amino Acids ◽  
Inhibitory Compounds ◽  
Spinal Neurones

The excitation of some neurones in the spinal cord of rats by L-glutamate and L-aspartate is followed by a period of reduced excitability. This effect is not observed after excitation by D-glutamate nor, in the case of Renshaw cells, by acetylcholine. The depressions following L-glutamate were reduced by bicuculline and those after aspartate by strychnine, suggesting that they may have been caused through decarboxylation of the excitatory amino acids to yield the inhibitory compounds γ-aminobutyric acid and β-alanine, respectively.

Specific effects of α-D,L-aminoadipic acid on synaptic transmission in frog spinal cord

1980 ◽  
Vol 58 (6) ◽  
pp. 692-698 ◽  
Author(s):  
Ante L. Padjen ◽  
Peter A. Smith
Keyword(s):  
Amino Acids ◽  
Spinal Cord ◽  
Dorsal Root ◽  
Lateral Column ◽  
Specific Effects ◽  
Acidic Amino Acids ◽  
Frog Spinal Cord ◽  
Gap Technique ◽  
Root Potential ◽  
Sucrose Gap

The sucrose gap technique was employed to investigate both synaptic and amino acid evoked responses from motoneurones or primary afferents of frog spinal cord. α-D,L-Aminoadipic acid (α-D,L-AAD) selectively antagonized responses to acidic amino acids, especially aspartate. The drug was most effective in antagonizing the polysynaptic components of synaptic potentials evoked by dorsal root or lateral column stimulation but had little effect on their monosynaptic components. The ventral root dorsal root potential which is thought to be mediated by a pathway that does not involve acidic amino acids was insensitive to α-D,L-AAD. These data, which were confirmed by intracellular recording from motoneurones, provided further evidence for the role of acidic amino acids in polysynaptic pathways in frog spinal cord.

The Role of Excitatory Amino Acids in Hypothermic Injury to Mammalian Spinal Cord Neurons

1996 ◽  
Vol 13 (12) ◽  
pp. 809-818 ◽  
Author(s):  
GEERT CRAENEN ◽  
SRDIJA JEFTINIJA ◽  
IVETA GRANTS ◽  
JEN HILL LUCAS
Keyword(s):  
Amino Acids ◽  
Spinal Cord ◽  
Excitatory Amino Acids ◽  
Spinal Cord Neurons ◽  
Hypothermic Injury

Excitatory amino acids rise to toxic levels upon impact injury to the rat spinal cord

1991 ◽  
Vol 547 (2) ◽  
pp. 344-348 ◽  
Author(s):  
Danxia Liu ◽  
Wipawan Thangnipon ◽  
David J. McAdoo
Keyword(s):  
Amino Acids ◽  
Spinal Cord ◽  
Excitatory Amino Acids ◽  
Rat Spinal Cord ◽  
Impact Injury

Excitatory amino acids: new tools for old stories or Pharmacological subtypes of glutamate receptors: electrophysiological studies

1991 ◽  
Vol 69 (7) ◽  
pp. 1123-1128 ◽  
Author(s):  
David Lodge ◽  
Martyn G. Jones ◽  
Andrew J. Palmer
Keyword(s):  
Amino Acids ◽  
Glutamate Receptors ◽  
Binding Sites ◽  
Excitatory Amino Acids ◽  
Channel Blocking ◽  
Electrophysiological Studies ◽  
Spinal Neurones ◽  
Potent Antagonist

Although the N-methyl-D-aspartate (NMDA) subtype of L-glutamate receptor is well characterized, the significance of non-NMDA glutamate-sensitive binding sites is not well documented. In this study, a new tricyclic quinoxalinedione (NBQX) and an arthropod toxin (philanthotoxin) were shown to block responses of spinal neurones in vivo to kainate, quisqualate, and AMPA in parallel but had little effect on responses to NMDA. Philanthotoxin appeared to be a use-dependent antagonist consistent with a channel-blocking mode of action. On cortical wedges in vitro, however, NBQX proved to be a more potent antagonist of AMPA and quisqualate than of kainate (pA2 values of 7.1, 7.0, and 5.6, respectively) with no effect at 10 μM on responses to NMDA. These studies provide evidence that on cortical neurones, but not on spinal neurones, AMPA and kainate depolarize by pharmacologically different mechanisms.Key words: glutamate receptors, quinoxalinediones, philanthotoxin, AMPA, kainate.

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