The role of NMDA and non-NMDA excitatory amino acid receptors in the functional organization of primate retinal ganglion cells

Vis Neurosci. Mar-Apr 1994;11(2):317-32. doi: 10.1017/s0952523800001668.

Abstract

The role of excitatory amino acid (EAA) receptors in primate retinal ganglion cell function was analyzed in a superfused retina-eyecup preparation using single-unit, extracellular recording techniques. The effects of bath applied L-2-amino-4-phosphonobutyrate (APB), N-methyl-D-aspartate (NMDA), and non-NMDA EAA receptor agonists and antagonists were examined on the light-evoked responses and resting firing rates of ganglion cells. APB (30-100 microM) reduced or blocked the light-evoked responses and resting firing rates of all ON-center ganglion cells; higher doses of APB (100 microM) were required to block the light-evoked responses of ON-transient cells. In contrast, an increase in resting firing rates was observed when L-APB was applied to some OFF-center ganglion cells. The EAA agonists kainate (KA) (10-20 microM) and NMDA (200-350 microM) increased the firing rate of virtually all ganglion cells examined. Quisqualate (10-20 microM) increased firing in most cells, but occasionally (4/13 cases) produced inhibition. The NMDA antagonist D-amino-phosphono-heptanoic acid (D-AP7) (200-250 microM) reduced the light-evoked responses of ganglion cells by an average of 12% from control levels, while resting firing rates declined 37%. In the presence of D-AP7, the basic receptive-field characteristics of cells were not significantly altered. In contrast, two non-NMDA receptor antagonists, NBQX (2,3-Dihydroxy-6-nitro-7-sulfamoyl-benzo-(F)-quinoxalinedione) and DNQX (6,7-dinitro-quinoxaline-2,3-dione), produced substantial reductions in the light-evoked responses (82%) and resting firing rates (87%) of all ganglion cell classes. A striking observation in some neurons was the recovery of a persistent transient light-evoked response in the presence of NBQX. This NBQX-insensitive, light-evoked response was always blocked by adding D-AP7. Thus, neurotransmission from bipolar to ganglion cells in primates is mediated predominantly by non-NMDA EAA receptors, with NMDA receptors forming a minor component of the light-evoked response.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Aminobutyrates / pharmacology
  • Animals
  • Electrophysiology
  • Interneurons / drug effects
  • Interneurons / physiology
  • Light
  • Macaca fascicularis
  • Macaca mulatta
  • N-Methylaspartate / pharmacology
  • Papio
  • Quinoxalines / pharmacology
  • Receptors, AMPA / antagonists & inhibitors
  • Receptors, AMPA / physiology
  • Receptors, Glutamate / drug effects
  • Receptors, Glutamate / physiology*
  • Receptors, N-Methyl-D-Aspartate / drug effects
  • Receptors, N-Methyl-D-Aspartate / physiology*
  • Retinal Ganglion Cells / drug effects
  • Retinal Ganglion Cells / physiology*

Substances

  • Aminobutyrates
  • Quinoxalines
  • Receptors, AMPA
  • Receptors, Glutamate
  • Receptors, N-Methyl-D-Aspartate
  • 2,3-dioxo-6-nitro-7-sulfamoylbenzo(f)quinoxaline
  • N-Methylaspartate
  • 2-amino-4-phosphonobutyric acid