PVP-containing solutions for analysis of divalent cation-dependent NMDA responses in Xenopus oocytes.
The electrophysiological analysis of Ca(2+)-conducting ion channels in Xenopus oocytes is difficult due to secondary intracellular effects induced by Ca2+. In the presence of polyvinylpyrrolidone (PVP) membrane currents can be recorded in nominally divalent cation-free solutions. The Ca(2+)-permeable recombinant NMDA receptors of the NR1/NR2A subtype were used as assay system and the results show that PVP has no effect on NMDA receptor-induced currents. Ca2+ and Ba2+ depress NMDA-induced currents at submillimolar concentrations probably by interfering with the Na+/K+ flux. This block is fully reversible as also observed for Mg2+ but shows in contrast no pronounced voltage dependence. PVP-containing solutions may be useful for the analysis of divalent cation-dependent ion channels.
Raditsch
M
M
Abteilung Zellphysiologie, Max-Planck-Institut für medizinische Forschung, Heidelberg, Germany.
Witzemann
V
V
D000818:Animals; D001464:Barium / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology; D002413:Cations, Divalent; D002462:Cell Membrane / Q000187:drug effects / Q000502:physiology; D004553:Electric Conductivity; D005260:Female; D005439:Flufenamic Acid; D007473:Ion Channels / Q000187:drug effects / Q000502:physiology*; D016202:N-Methylaspartate / Q000494:pharmacology*; D009865:Oocytes / Q000502:physiology*; D011205:Povidone / Q000494:pharmacology; D016194:Receptors, N-Methyl-D-Aspartate / Q000502:physiology; D012996:Solutions; D014981:Xenopus
D002413:Cations, Divalent; D007473:Ion Channels; D016194:Receptors, N-Methyl-D-Aspartate; D012996:Solutions; D001464:Barium; D005439:Flufenamic Acid; D016202:N-Methylaspartate; D011205:Povidone; D002118:Calcium