Expression of mammalian gamma-aminobutyric acid receptors with distinct pharmacology in Xenopus oocytes

Proc Natl Acad Sci U S A. 1991 May 15;88(10):4318-22. doi: 10.1073/pnas.88.10.4318.

Abstract

Gamma-Aminobutyric acid (GABA), the major inhibitory neurotransmitter in mammalian brain, is known to interact with two classes of GABA receptors denoted GABAA and GABAB. Using Xenopus oocytes, we compared the electrical and pharmacological properties of GABA receptors expressed by poly(A)+ RNA isolated from mammalian brain and retina. RNA from cerebral cortex expressed GABA responses with features characteristic of currents mediated by GABAA receptors. In contrast, RNA from retina expressed responses mediated by GABAA receptors and, in addition, GABA responses that were insensitive to the GABAA antagonist bicuculline and the GABAB agonist baclofen and showed no modulation by barbiturates or benzodiazepines. The bicuculline/baclofen-insensitive GABA response was a Cl- current that was blocked by picrotoxin but showed little desensitization or outward rectification. Our results suggest that mammalian retina contains RNAs encoding GABA receptors with distinct pharmacology.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Baclofen / pharmacology
  • Bicuculline / pharmacology
  • Cattle
  • Cerebral Cortex / chemistry
  • Electric Conductivity
  • Gene Expression*
  • Membrane Potentials
  • Oocytes / physiology*
  • Pentobarbital / pharmacology
  • Picrotoxin / pharmacology
  • Poly A / genetics
  • RNA / genetics
  • RNA, Messenger
  • Rats
  • Receptors, GABA-A / drug effects
  • Receptors, GABA-A / genetics*
  • Receptors, GABA-A / physiology
  • Retina / chemistry
  • Transfection
  • Xenopus
  • gamma-Aminobutyric Acid / pharmacology

Substances

  • RNA, Messenger
  • Receptors, GABA-A
  • Picrotoxin
  • Poly A
  • gamma-Aminobutyric Acid
  • RNA
  • Baclofen
  • Pentobarbital
  • Bicuculline