The effects of glycine and GABA on isolated horizontal cells from the salamander retina

J Neurophysiol. 1991 Dec;66(6):2002-13. doi: 10.1152/jn.1991.66.6.2002.


1. Horizontal cells, identified by their morphology, were isolated from the salamander retina and examined in whole cell patch clamp. 2. All cells showed large outward currents activating positive to about -50 mV, and a minority of cells showed fast, tetrodotoxin-suppressible Na+ currents. Slow inward currents that might shape the light responses were never observed. 3. All cells showed conductance increases to both gamma-aminobutyric acid (GABA) and glycine that were completely blocked by bicuculline and strychnine, respectively. No cross-blocking by these antagonists was observed. Partial replacements of Cl- with large, impermeant anions indicated that both GABA- and glycine-evoked currents were carried by Cl- ions. 4. Responses to both GABA and glycine desensitized strongly with time constants of approximately 2 s. 5. Responses to glutamate were not enhanced by glycine. Similarly, responses to GABA were not enhanced by glutamate. 6. GABA-mediated synaptic interactions between horizontal cells may account for the changes in the kinetics of horizontal cell light responses seen when glycine is applied to the intact retina.

Publication types

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

MeSH terms

  • Action Potentials / drug effects
  • Ambystoma / physiology*
  • Animals
  • Bicuculline / pharmacology
  • Darkness
  • Electrophysiology / methods
  • Glycine / pharmacology*
  • In Vitro Techniques
  • Kinetics
  • Membrane Potentials / drug effects
  • Models, Neurological
  • Neurons / physiology
  • Photic Stimulation
  • Photoreceptor Cells / physiology
  • Retina / cytology
  • Retina / drug effects
  • Retina / physiology*
  • Strychnine / pharmacology
  • Time Factors
  • gamma-Aminobutyric Acid / pharmacology*


  • gamma-Aminobutyric Acid
  • Strychnine
  • Glycine
  • Bicuculline