Synthesis of functional chick brain GABA-benzodiazepine-barbiturate/receptor complexes in mRNA-injected Xenopus oocytes.

Membrane conductance changes evoked by bath-applied GABA (2-640 microM) and some related agonists were recorded intracellularly in Xenopus oocytes previously injected with chick brain mRNA. Muscimol and 3-aminopropanesulphonate were approximately 4 and 0.25 times as potent as GABA in producing a conductance increase. GABA responses were antagonized by bicuculline (10 microM) or picrotoxinin (10-100 microM) but were clearly enhanced by the benzodiazepine (BZ) receptor ligand chlorazepate or by pentobarbitone. We conclude that an appropriate fraction of brain mRNA was capable of directing the synthesis and correct insertion of functional GABA-BZ-barbiturate/receptor complexes in the oocyte membrane.