Properties of human brain glycine receptors expressed in Xenopus oocytes

Abstract

Glycine and γ-aminobutyric acid (GABA) receptors from the foetal human brain were ‘transplanted’ into the Xenopus oocyte membrane by injecting the oocytes with poly(A)⁺-mRNA extracted from the cerebral cortex. Activation of both glycine and GABA receptors induced membrane currents carried largely by chloride ions. However, unlike the GABAactivated current, the glycine current was blocked by strychnine, and was not potentiated by barbiturate. At low doses, the glycine current increased with concentration following a 2.7th power relation, suggesting that binding of three molecules of glycine may be required to open a single membrane channel. The current induced by steady application of glycine decreased with hyperpolarization beyond about —60 mV.