Document Detail


Amino acids as neurotransmitters of corticofugal neurones in the rat: a comparison of glutamate and aspartate.
MedLine Citation:
PMID:  42459     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
1 The relative sensitivities to aspartate and glutamate of neurones receiving a corticofugal innervation were examined by microiontophoresis, and compared with the relative sensitivities of neurones not appearing to receive such an input.2 On all the cells tested, glutamate appeared to be a more potent excitant than aspartate in terms of neuronal response size or effective dose.3 DL-alpha-Aminoadipate (alphaAA) reduced the excitatory amino acid responses on all the neurones tested. On many of these cells a control excitation could be produced, by acetylcholine or hydrogen ions, which was in most cases unaffected by doses of alphaAA producing antagonism of amino acid excitation.4 On 70% of the cells, aminoadipate showed no selectivity for aspartate compared with glutamate but a differential action, involving blockade of aspartate but not glutamate, was apparent on the other 30%.5 Doses of alphaAA which selectively reduced responses to aspartate had no effect on short latency evoked spikes, but doses which also reduced responses to glutamate reduced the short-latency synaptic excitation induced by electrical stimulation of either the surface of the cerebral cortex, or of the pyramidal tracts in the medulla.6 These findings suggest that corticofugal neurones having an excitatory action on cells in various parts of the brain may use an amino acid, probably glutamate, as a common neurotransmitter.7 As no significant difference could be demonstrated in the potency ratios of glutamate:aspartate on monosynaptically activated cells compared with other cells, doubt is cast on the validity of drawing conclusions about transmitter identity from potency ratios alone, without the support of antagonist studies.
Authors:
T W Stone
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Publication Detail:
Type:  Comparative Study; Journal Article    
Journal Detail:
Title:  British journal of pharmacology     Volume:  67     ISSN:  0007-1188     ISO Abbreviation:  Br. J. Pharmacol.     Publication Date:  1979 Dec 
Date Detail:
Created Date:  1980-03-27     Completed Date:  1980-03-27     Revised Date:  2009-11-18    
Medline Journal Info:
Nlm Unique ID:  7502536     Medline TA:  Br J Pharmacol     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  545-51     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
2-Aminoadipic Acid / pharmacology
Animals
Aspartic Acid / physiology*
Cerebral Cortex / physiology*
Glutamates / physiology*
Iontophoresis
Male
Neurons / drug effects,  physiology
Neurotransmitter Agents*
Rats
Synapses / drug effects
Chemical
Reg. No./Substance:
0/Glutamates; 0/Neurotransmitter Agents; 542-32-5/2-Aminoadipic Acid; 56-84-8/Aspartic Acid
Comments/Corrections

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