Blocking the trigeminal EPSP in rat abducens motoneurons in vivo with the AMPA antagonists NBQX and GYKI 53655.

Ruiz, A. and Durand, J. (2000) Blocking the trigeminal EPSP in rat abducens motoneurons in vivo with the AMPA antagonists NBQX and GYKI 53655. Brain Research Bulletin, 52 (2). pp. 99-107. 10.1016/S0361-9230(00)00243-4.

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DOI: 10.1016/S0361-9230(00)00243-4


In pentobarbitone-anaesthetized rats, the effects of two AMPA receptor antagonists, the competitive antagonist 2, 3-dihydroxy-6-nitro-7-sulfamoyl-benzo-(F)-quinoxaline (NBQX) and the non-competitive 2,3-benzodiazepine GYKI 53655, were compared on excitatory synaptic transmission of trigeminal origin in intracellularly-recorded abducens motoneurons. The effects of both antagonists were also investigated on the alpha-amino-3-hydroxy-5-methyl isoxazole-4-propionic acid (AMPA)-, kainate-, and N-methyl-D-aspartate (NMDA)-induced depression of extracellular antidromic field potentials in the abducens motor nucleus. Microiontophoretic application (< or =100 nA) or intravenous injection of NBQX (< or =5 mg/kg) affected both AMPA- and kainate-induced depressions whereas GYKI 53655 (< or =100 nA; < or =4 mg/kg) blocked only the AMPA-induced depression. Neither NBQX or GYKI 53655 affected NMDA-induced depressions of antidromic field potentials. Using low intravenous (i.v.) doses of the antagonists NBQX or GYKI 53655 (2-2.5 mg/kg), a complete blockade of the composite disynaptic trigeminal excitatory post-synaptic potential (EPSP) was obtained without any changes in membrane potential, input resistance and antidromic action potentials in abducens motoneurons. GYKI 53655 was more potent at low i.v. doses (0.5-1.8 mg/kg) but NBQX had longer-lasting effects. The results show the existence of differences between the blocking action of NBQX and GYKI 53655 on AMPA-mediated receptor EPSP in abducens motoneurons.

Item Type:Article
Uncontrolled Keywords:2; 3-Benzodiazepines; Quinoxalinediones; Allosteric modulators; Intracellular recordings; Kainate
Departments, units and centres:Department of Pharmacology > Department of Pharmacology
ID Code:2456
Journal or Publication Title:Brain Research Bulletin
Deposited By:Library Staff
Deposited On:11 Nov 2011 11:30
Last Modified:11 Nov 2011 11:30

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