Use of ligands with low nanomolar affinity for the GABAB receptor: Effect of CGP 55845A on the release of amino acids

J. Kardos, T. Blandl, I. Kovács, K. A. Kékesi, A. Reichart, G. Nyitrai, Á Dobolyi, G. Juhász

Research output: Contribution to journalArticle

2 Citations (Scopus)


To assess antagonistic properties of the nanomolar affinity GABAB receptor ligand, CGP 55845A (IC50 = 1.1 ± 0.2 nM), 3H-D-Aspartate release from synaptosomes at 22-24°C was measured in combination with the use of a fast perfusion technique, in vitro. The inhibition of high K+ elicited 3H-D-aspartate release by 250 μM (R)-baclofen was blocked by 10 μM CGP 55845A. The concomitant two-fold increase of basal aspartate release was comparable to that of freely moving rats as measured by a HPLC combined microdialysis technique, in vivo. A low concentration of CGP 55845A (250 nM) induced two release-pulses of glutamate whereas much less or no release (or release inhibition) was detected with aspartate, serine, glycine and glutamine. By contrast, one order of magnitude higher dose of CGP 55845A induced similar, double-release patterns of neurotransmitters and serine, however the relative amounts of released glutamate (15-fold) and aspartate (55-fold) were reversed in the second pulse.

Original languageEnglish
Pages (from-to)153-157
Number of pages5
JournalPharmacology Reviews and Communications
Issue number2-3
Publication statusPublished - Dec 1 1996


  • Amino acids
  • Freely moving rat
  • H-D-Aspartate release
  • H-R-Baclofen binding
  • Microdialysis
  • Synaptosomal fraction

ASJC Scopus subject areas

  • Pharmacology

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