Xenopus Oocyte Expression System Establishment And Expression Of Nmda Receptor Pharmacological Properties

Objective: The expression system of African Xenopus laevis oocytes is powerful and widely used. Different kinds and function of protein can be expressed in oocytes of Xenopus laevis. To establish expression system of Xenopus laevis oocytes. Study the structure and function of expressing receptor protein. Methods: The two-electrode voltage clamp recording technique was used to observe the ligand-gated and voltage-gated ion channel currents expressed in Xenopus laevis oocytes without follicles. cDNAs, including NR2A, NR2B and NR1A transcribed in vitro. And then they were microinjected into the oocyte cytoplasm to express receptors. Expressed activation currents including NR1A /NR2A and NR1A /NR2B can be recorded using the technique. And we studied pharmacological properties of different sub-types of NMDA receptors. Results: There were no visible currents induced in Xenopus leavis oocyte which were not microinjected when NMDA, γ-GABA and nicotine were added in the perfusion fluids, respectively. Membrane depolarization could revoke an outward current. The amplitude of currents increased when Ca²⁺ concentration in the extracellular fluids was raised. The currents disappeared in the extracellular solution without Ca²⁺ and/or Cl^-. The outward currents could be blocked by MnCl₂, but not TEA. Inward currents could be induced in the microinjected (NR1A/2A and NR1A/2B) oocytes when NMDA receptor agnists glutamate and glycine were added in the perfusion fluids simultaneously. Antagonist haloperidol inhibited current of NR1A/2B selectively. NMDA receptor currents (NR1A/2A and NR1A/2B) were reversibily blocked by agmatine and Phencynonate hydrochloride optical isomoters. The blockage possessed concentration- and voltage-dependent. Conclusions: The expression system of Xenopus laevis oocytes was successfully established. Using two-electrode voltage clamp recording technique to study about pharmacological properties of expressed different sub-types of NMDA receptors. Finding was that NMDA receptor currents (NR1A/2A and NR1A/2B) were reversibily blocked by agmatine and...