Linked Life Data

3021930

Source:http://linkedlifedata.com/resource/pubmed/id/3021930

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
11
pubmed:dateCreated
1986-12-11
pubmed:abstractText
We examined the membrane action of the endogenous dipeptide and putative neurotransmitter N-acetylaspartylglutamate (NAAG) on the excitatory amino acid receptors of cultured mouse spinal cord neurons using electrophysiological methods. Responses to NAAG (1 microM-5 mM) were compared to those elicited by N-methyl-D-aspartate (1 microM-1 mM) and L-glutamate (0.5-500 microM). Under voltage clamp, concentration-response curves of agonist-evoked currents demonstrated that NAAG was much less potent than either L-glutamate or N-methyl-D-aspartate (NMDA), so that inward currents could be evoked only at NAAG concentrations above 300 microM. Analysis of the dipeptide by high-pressure liquid chromatography showed no evidence of contamination by excitatory amino acids, suggesting that NAAG has an intrinsic, although weak, neuroexcitatory action on spinal neurons. Previous studies have shown that activation of NMDA receptors produces a voltage-dependent response. The current-voltage relationship of responses evoked by NAAG was also voltage-dependent. The peptide-activated conductance decreased with hyperpolarization in the presence of extracellular Mg2+, such that little inward current could be evoked at a membrane potential of -80 mV. In addition, responses to NAAG were completely antagonized by 250 microM DL-2-amino-5-phosphonovaleric acid, a specific NMDA-receptor antagonist. Application of NAAG in Mg2+-free medium resulted in an inward current with a large increase in membrane current noise. The spectral density function of this current noise could be fitted with a single Lorentzian with a decay time constant near 5 msec and a calculated single-channel conductance of 50-60 pS.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0270-6474
pubmed:author
pubmed:issnType
Print
pubmed:volume
6
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3385-92
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
1986
pubmed:articleTitle
High concentrations of N-acetylaspartylglutamate (NAAG) selectively activate NMDA receptors on mouse spinal cord neurons in cell culture.
pubmed:publicationType
Journal Article