Article: article from journal or magazin.
Blockade of ion channel expression in Xenopus oocytes with complementary DNA probes to Na+ and K+ channel mRNAs
Journal Article --- Old month value: Dec
Ionic currents were recorded from Xenopus oocytes injected with RNA isolated from chick or mouse brain. Three currents were studied: a rapid tetrodotoxin-sensitive Na+ current (Ina), an early outward K+ current sensitive to 4-aminopyridine (IA), and an inward current activated by the excitatory amino acid receptor agonist kainate. Oligonucleotides (60-80 bases long) complementary to rat brain Na+ channel sequences were prehybridized to chick brain RNA. These DNA sequences, upon injection into oocytes, specifically inhibited expression of INa relative to IA and the kainate-induced current in a dose-dependent manner. By contrast, prehybridization of oligonucleotides complementary to sequences either from the Drosophila Shaker locus (which codes for an early K+ current in Drosophila muscle) or from a homologous clone from mouse brain did not block the expression of the early outward K+ current induced in the oocytes by mRNA from chick or mouse brain. This method provides a convenient means for testing the functional role of cloned DNA species.
Animals Base Sequence Cell Membrane/metabolism/physiology Cell Membrane Permeability/drug effects/physiology DNA/genetics/pharmacology *DNA Probes Drosophila/genetics Electric Conductivity Female Genes, Regulator/physiology Kainic Acid/pharmacology Molecular Sequence Data Oocytes/drug effects/*physiology/ultrastructure Potassium/metabolism Potassium Channels/*drug effects/physiology Protein Biosynthesis RNA, Messenger/*genetics/pharmacology Sodium/metabolism Sodium Channels/*drug effects/physiology Xenopus/*physiology
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