Functional brain GABA and glycine receptors in mRNA-injected Xenopus oocytes

Changes in membrane potential and conductance evoked by GABA were measured in Xenopus ooctyes injected with chick or rat brain mRNA. GABA responses were antagonized by bicuculline or picrotoxinin but enhanced by chlorazepate or by pentobarbitone. Oocytes injected with rat brain mRNA responded similarly to both GABA and glycine. Strychnine selectively depressed glycine responses, whereas picrotoxinin antagonized both GABA and glycine effects non-specifically. GABA (but not glycine) responses were enhanced by pentobarbitone. The cells also responded dose-dependently to glutamate, aspartate and kainate, indicating that this mRNA fraction was directing the appearance of a variety of functional neurotransmitter receptors.