title: The effects of glycine and GABA on isolated horizontal cells from the salamander retina.
abstract: 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.
authors.affiliation: Department of Zoology, University of California, Davis 95616.
authors.forename: T A
authors.initials: TA
authors.lastname: Gilbertson
authors.forename: S
authors.initials: S
authors.lastname: Borges
authors.forename: M
authors.initials: M
authors.lastname: Wilson
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000557:Ambystoma / Q000502:physiology*; D000818:Animals; D001640:Bicuculline / Q000494:pharmacology; D003624:Darkness; D004594:Electrophysiology / Q000379:methods; D005998:Glycine / Q000494:pharmacology*; D066298:In Vitro Techniques; D007700:Kinetics; D008564:Membrane Potentials / Q000187:drug effects; D008959:Models, Neurological; D009474:Neurons / Q000502:physiology; D010775:Photic Stimulation; D010786:Photoreceptor Cells / Q000502:physiology; D012160:Retina / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D013331:Strychnine / Q000494:pharmacology; D013997:Time Factors; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology*
chemical_list: D005680:gamma-Aminobutyric Acid; D013331:Strychnine; D005998:Glycine; D001640:Bicuculline