Coexistence and function of glutamate receptor subtypes in the horizontal cells of the tiger salamander retina

Vis Neurosci. 1991 Oct;7(4):377-82. doi: 10.1017/s0952523800004867.


Effects of the major glutamate receptor agonists, kainate (KA), alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA), quisqualate (QA), N-methyl-D-aspartate (NMDA), L-alpha-amino-4-phosphonobutyrate (L-AP4), and trans-1-aminocyclopentane-1,3-dicarboxylic acid (ACPD) on horizontal cells (HCs) were studied in superfused larval tiger salamander retina. 20 microM of KA, AMPA, and QA mimicked the action of 3 mM glutamate in the absence and presence of 1 mM Co2+. 20 microM 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) blocked the actions of KA and AMPA, but not those of QA and glutamate, indicative of the existence of CNQX-resistant QA receptors in the tiger salamander HCs. Prolonged application of ACPD hyperpolarized the HCs and enhanced the light responses, probably by shifting the resting HC voltage (Er) to a more hyperpolarized position. It is possible that the KA, AMPA, and CNQX-resistant QA receptors are involved in mediating the postsynaptic light responses in HCs, and ACPD receptors are involved in sensitivity adjustment of the HC responses.

Publication types

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

MeSH terms

  • Animals
  • Dark Adaptation
  • Electrophysiology
  • Glutamates / pharmacology
  • Heterocyclic Compounds / pharmacology
  • Membrane Potentials
  • Photic Stimulation
  • Receptors, Glutamate
  • Receptors, Neurotransmitter / physiology*
  • Retina / drug effects
  • Retina / physiology*
  • Urodela


  • Glutamates
  • Heterocyclic Compounds
  • Receptors, Glutamate
  • Receptors, Neurotransmitter