Regulation of polyamine and magnesium inhibition of the N-methyl-d-aspartate (NMDA) receptor ionophore complex

Aida I. Sacaan, Kenneth M. Johnson

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

The inhibitory effects of spermidine, putrescine and magnesium on [3H]TCP binding in crude synaptosomes and well washed buffy coat membranes were studied. We report that the IC50 values for the drugs tested varied depending on the state of activation of the channel, being lowest when the channel is maximally activated and highest when the channel is least activated in the control buffy coat preparation. Comparison of the inhibitory characteristics of these 3 agents when activated by glutamate, glycine, and low concentrations of spermidine or magnesium strongly suggest that putrescine and magnesium share a common inhibitory mechanism, perhaps mediated by the voltage-dependent channel site for magnesium. Inhibition by spermidine, however, is clearly mediated by a distinct site, non-identical to the phencyclidine receptor. Glutamate appears to uncouple this inhibition in about one-half of the N-methyl-d-aspartate (NMDA) complexes, suggesting the possibility of distinct subpopulations of NMDA-operated ion channels. The potential physiological relevance of these findings is discussed.

Original languageEnglish (US)
Pages (from-to)219-222
Number of pages4
JournalNeuroscience Letters
Volume121
Issue number1-2
DOIs
StatePublished - Jan 2 1991

Fingerprint

Ionophores
Polyamines
Magnesium
Spermidine
Putrescine
Aspartic Acid
Glutamic Acid
Phencyclidine Receptors
Synaptosomes
Ion Channels
Glycine
Inhibitory Concentration 50
Membranes
aspartic acid receptor
Pharmaceutical Preparations

Keywords

  • Magnesium
  • NMDA
  • Polyamine
  • Putrescine
  • Spermidine

ASJC Scopus subject areas

  • Neuroscience(all)

Cite this

Regulation of polyamine and magnesium inhibition of the N-methyl-d-aspartate (NMDA) receptor ionophore complex. / Sacaan, Aida I.; Johnson, Kenneth M.

In: Neuroscience Letters, Vol. 121, No. 1-2, 02.01.1991, p. 219-222.

Research output: Contribution to journalArticle

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