The rat beta 1-subunit of the GABAA receptor forms a picrotoxin-sensitive anion channel open in the absence of GABA

FEBS Lett. 1989 Nov 6;257(2):377-9. doi: 10.1016/0014-5793(89)81576-5.


The structural basis of GABA-gated chloride channels in mammalian brain is presently explored by the functional expression of cDNAs coding for the alpha, beta or gamma-subunits of the receptor and their isoforms. In this context, we expressed the cloned cDNA coding for the rat beta 1-subunit of the GABAA receptor in the Xenopus oocyte. Surprisingly, efficient expression of a functional ion channel was found. The channel was anion-selective, and able to open in the absence of GABA. Since this channel could be shunt by the GABA-channel blocker picrotoxin, we conclude that the beta 1-subunit of the GABAA receptor is sufficient to form binding sites for picrotoxin.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anions
  • Carbolines / pharmacology
  • Diazepam / pharmacology
  • Ion Channels*
  • Macromolecular Substances
  • Membrane Potentials
  • Picrotoxin / pharmacology
  • Rats
  • Receptors, GABA-A / genetics
  • Receptors, GABA-A / metabolism
  • Receptors, GABA-A / ultrastructure*
  • Xenopus laevis
  • gamma-Aminobutyric Acid / metabolism*


  • Anions
  • Carbolines
  • Ion Channels
  • Macromolecular Substances
  • Receptors, GABA-A
  • Picrotoxin
  • methyl 6,7-dimethoxy-4-ethyl-beta-carboline-3-carboxylate
  • gamma-Aminobutyric Acid
  • Diazepam