Voltage- and transmitter-gated currents of all-amacrine cells in a slice preparation of the rat retina

J Neurosci. 1993 Jul;13(7):2874-88. doi: 10.1523/JNEUROSCI.13-07-02874.1993.

Abstract

All-amacrine cells are crucial interneurons in the rod pathway of the mammalian retina. They receive input synapses from rod bipolar cells and make electrical output synapses into the ON-pathway and glycinergic chemical synapses into the OFF-pathway. Whole-cell currents from more than 50 voltage-clamped All-amacrine cells were recorded in a slice preparation of the rat retina. The recorded cells were identified by intracellular staining with Lucifer yellow. Spike-like potentials could be elicited upon depolarization by current injection. A voltage-activated, fast, TTX-sensitive, inward Na+ current was identified. A prominent outward K+ current could be suppressed by tetraethylammonium. GABA as well as glycine activated Cl- channels, which could be blocked by bicuculline and strychnine, respectively. Four agonists of excitatory amino acid receptors--kainate (KA), AMPA, 2-amino-4-phosphonobutyrate (APB), and NMDA--were tested. Inward currents at holding potentials of VH = -70 mV were found by application of KA and AMPA but not by application of APB and NMDA. These currents could be blocked by 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX). ACh did not evoke any current responses.

MeSH terms

  • 4-Aminopyridine / pharmacology
  • 6-Cyano-7-nitroquinoxaline-2,3-dione
  • Aminobutyrates / pharmacology
  • Animals
  • Cobalt / pharmacology
  • Electrophysiology / methods
  • Glutamates / pharmacology
  • Glutamic Acid
  • Glycine / pharmacology
  • Ibotenic Acid / analogs & derivatives
  • Ibotenic Acid / pharmacology
  • In Vitro Techniques
  • Ion Channel Gating / drug effects
  • Ion Channels / drug effects
  • Ion Channels / physiology*
  • Kainic Acid / pharmacology
  • Membrane Potentials / drug effects
  • N-Methylaspartate / pharmacology
  • Potassium Channels / drug effects
  • Potassium Channels / physiology
  • Quinoxalines / pharmacology
  • Rats
  • Receptors, Amino Acid / drug effects
  • Receptors, Amino Acid / physiology
  • Retina / cytology*
  • Retina / drug effects
  • Retina / physiology*
  • Retinal Ganglion Cells / physiology
  • Sodium Channels / physiology
  • Strychnine / pharmacology
  • Synapses / drug effects
  • Synapses / physiology
  • Tetraethylammonium
  • Tetraethylammonium Compounds / pharmacology
  • Tetrodotoxin / pharmacology
  • alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid
  • gamma-Aminobutyric Acid / pharmacology*

Substances

  • Aminobutyrates
  • Glutamates
  • Ion Channels
  • Potassium Channels
  • Quinoxalines
  • Receptors, Amino Acid
  • Sodium Channels
  • Tetraethylammonium Compounds
  • Ibotenic Acid
  • Cobalt
  • Glutamic Acid
  • Tetrodotoxin
  • gamma-Aminobutyric Acid
  • N-Methylaspartate
  • Tetraethylammonium
  • 6-Cyano-7-nitroquinoxaline-2,3-dione
  • alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid
  • 4-Aminopyridine
  • 2-amino-4-phosphonobutyric acid
  • Strychnine
  • Kainic Acid
  • Glycine