Uridine activates fast transmembrane Ca2+ ion fluxes in rat brain homogenates

Julianna Kardos, Ilona Kovács, Éva Szárics, Richárd Kovács, Nina Skuban, Gabriella Nyitrai, Árpád Dobolyi, Gábor Juhász

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

The excitatory actions of the pyrimidine nucleoside uridine, and the nucleotides UDP and UTP, as well as the purine nucleotide ATP, were studied by fluorescent labeling of Ca2+ and K+ ion fluxes on the time scale of 0.04 ms to 10s in resealed plasmalemma fragments and nerve endings from the rat cerebral cortex. Two phases of Ca2+ ion influx with onsets of a few milliseconds and a few hundred milliseconds, showing different concentration dependencies, agonist sequences and subcellular localizations were distinguishable. [3H]Uridine identified high (KD ~15nM) and low affinity (KD ~1 μM) specific binding sites in purified synaptosomal membranes. Labeled uridine taken up by synaptosomes in a dipyridamole-sensitive process was released by depolarization (1mM 4-aminopyridine). Taken together, these results may qualify uridine as a neurotransmitter.

Original languageEnglish
Pages (from-to)1577-1582
Number of pages6
JournalNeuroreport
Volume10
Issue number7
DOIs
Publication statusPublished - May 14 1999

Keywords

  • Binding
  • Ca influx
  • Rat cerebral cortex
  • Release
  • Uptake
  • Uridine

ASJC Scopus subject areas

  • Neuroscience(all)

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