GABA receptors on horizontal cells in the goldfish retina

Vision Res. 2003 Sep;43(20):2101-6. doi: 10.1016/s0042-6989(03)00335-3.

Abstract

We investigated the localization of GABA(A) and GABA(C) receptors in horizontal cells (HCs) and HC axon terminals (ATs) dissociated from goldfish retina, using whole-cell patch-clamping recordings. Applications of GABA on HCs induced two groups with inward currents at the holding potential of -50 mV: One was a sustained inward current in the H1 cell, with one type of HCAT (AT1), and the other was a transient inward current in other HC soma and HCAT (AT2). Co-application of GABA with bicuculline or SR95531, GABA(A) receptor antagonists, showed a non-blocking effect in the sustained current, but a blocking effect in the transient current. The sustained current was evoked by cis-4-aminocrotonic acid (CACA), a GABA(C) receptor agonist, while the transient current was not induced by CACA, but mimicked by muscimol, a GABA(A) receptor agonist. Both the sustained and transient currents were completely blocked by picrotoxin and not mimicked by baclofen, a GABA(B) receptor agonist. Thus H1 cell and AT1 have GABA(C) receptors, while H2, H3 cells and AT2 have GABA(A) receptors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Electrophysiology
  • GABA Agonists / pharmacology
  • GABA Antagonists / pharmacology
  • Goldfish
  • Patch-Clamp Techniques
  • Receptors, GABA / physiology*
  • Retina / cytology*
  • Retina / physiology

Substances

  • GABA Agonists
  • GABA Antagonists
  • Receptors, GABA