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A K+ channel in Xenopus nerve fibres selectively blocked by bee and snake toxins: binding and voltage-clamp experiments.
Bräu ME
,
Dreyer F
,
Jonas P
,
Repp H
,
Vogel W
.
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1. The effects of mast cell degranulating peptide (MCDP), a toxin from the honey bee, and of dendrotoxin (DTX), a toxin from the green mamba snake, were studied in voltage-clamp experiments with myelinated nerve fibres of Xenopus. 2. MCDP and DTX blocked part of the K+ current. About 20% of the K+ current, however, was resistant to the toxins even in high concentrations. In Ringer solution half-maximal block was reached with concentrations of 33 nM-MCDP and 11 nM-DTX. In high-K+ solution the potency of both toxins was lower. beta-Bungarotoxin (beta-BuTX), another snake toxin, also blocked part of the K+ current, but was less potent than MCDP and DTX. 3. Tail currents in high-K+ solution were analysed and three K+ current components were separated according to Dubois (1981 b). Both MCDP and DTX selectively blocked a fast deactivating, slowly inactivating K+ current component which steeply activates between E = -60 mV and E = -40 mV (component f1). In concentrations around 100 nM, MCDP and DTX blocked neither the slow K+ current (component s) nor the fast deactivating, rapidly inactivating K+ current which activates between E = -40 mV and E = 20 mV (component f2). Similar results could be derived from K+ outward currents in Ringer solution. In high-K+, IC50 of MCDP for component f1 was 99 nM, whereas it was 7.6 microM for f2. Corresponding values for DTX are 68 nM and 1.8 microM. 4. Binding studies with nerve fibre membranes of Xenopus reveal high-affinity binding sites for 125I-labelled DTX (KD = 22 pM in Ringer solution and 81 pM in high-K+ solution). 125I-labelled DTX can be displaced from its sites completely by unlabelled DTX, toxin I (black mamba toxin), MCDP, and partially by beta-BuTX. 5. Immunocytochemical staining demonstrates that binding sites for DTX are present in nodal and paranodal regions of the axonal membrane. 6. The axonal membrane of motor and sensory nerve fibres is equipped with three types of well-characterized K+ channels and constitutes so far the best preparation to study MCDP- and DTX-sensitive K+ channels with electrophysiological and biochemical methods.
Baumann,
Structure of the voltage-dependent potassium channel is highly conserved from Drosophila to vertebrate central nervous systems.
1988, Pubmed
Baumann,
Structure of the voltage-dependent potassium channel is highly conserved from Drosophila to vertebrate central nervous systems.
1988,
Pubmed
Benoit,
Toxin I from the snake Dendroaspis polylepis polylepis: a highly specific blocker of one type of potassium channel in myelinated nerve fiber.
1986,
Pubmed
Bidard,
Two potent central convulsant peptides, a bee venom toxin, the MCD peptide, and a snake venom toxin, dendrotoxin I, known to block K+ channels, have interacting receptor sites.
1987,
Pubmed
Black,
Two acceptor sub-types for dendrotoxin in chick synaptic membranes distinguishable by beta-bungarotoxin.
1986,
Pubmed
Bradford,
A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding.
1976,
Pubmed
Dreyer,
The actions of presynaptic snake toxins on membrane currents of mouse motor nerve terminals.
1987,
Pubmed
Dubois,
Simultaneous changes in the equilibrium potential and potassium conductance in voltage clamped Ranvier node in the frog.
1981,
Pubmed
Dubois,
Evidence for the existence of three types of potassium channels in the frog Ranvier node membrane.
1981,
Pubmed
Dubois,
Capsaicin blocks one class of K+ channels in the frog node of Ranvier.
1982,
Pubmed
Grissmer,
Properties of potassium and sodium channels in frog internode.
1986,
Pubmed
Habermann,
Bee and wasp venoms.
1972,
Pubmed
Halliwell,
Central action of dendrotoxin: selective reduction of a transient K conductance in hippocampus and binding to localized acceptors.
1986,
Pubmed
Harvey,
Protease inhibitor homologues from mamba venoms: facilitation of acetylcholine release and interactions with prejunctional blocking toxins.
1982,
Pubmed
Hille,
Local anesthetics: hydrophilic and hydrophobic pathways for the drug-receptor reaction.
1977,
Pubmed
Jennrich,
Fitting nonlinear models to data.
1979,
Pubmed
Mehraban,
Identification by cross-linking of a neuronal acceptor protein for dendrotoxin, a convulsant polypeptide.
1984,
Pubmed
Nonner,
A new voltage clamp method for Ranvier nodes.
1969,
Pubmed
Penner,
Dendrotoxin: a selective blocker of a non-inactivating potassium current in guinea-pig dorsal root ganglion neurones.
1986,
Pubmed
Petersen,
Beta-bungarotoxin inhibits a non-inactivating potassium current in guinea pig dorsal root ganglion neurones.
1986,
Pubmed
Plant,
The effects of rubidium ions on components of the potassium conductance in the frog node of Ranvier.
1986,
Pubmed
Röper,
Heterogeneous distribution of fast and slow potassium channels in myelinated rat nerve fibres.
1989,
Pubmed
Salacinski,
Iodination of proteins, glycoproteins, and peptides using a solid-phase oxidizing agent, 1,3,4,6-tetrachloro-3 alpha,6 alpha-diphenyl glycoluril (Iodogen).
1981,
Pubmed
Schmidt,
Inhibition of beta-bungarotoxin binding to brain membranes by mast cell degranulating peptide, toxin I, and ethylene glycol bis (beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid.
1988,
Pubmed
Schwarz,
Potassium inactivation in single myelinated nerve fibres of Xenopus laevis.
1971,
Pubmed
,
Xenbase
Stansfeld,
Mast cell degranulating peptide and dendrotoxin selectively inhibit a fast-activating potassium current and bind to common neuronal proteins.
1987,
Pubmed
Stansfeld,
Dendrotoxin-sensitive K+ channels in dorsal root ganglion cells.
1988,
Pubmed
Stühmer,
Potassium channels expressed from rat brain cDNA have delayed rectifier properties.
1988,
Pubmed
,
Xenbase
Taylor,
The characterization of high-affinity binding sites in rat brain for the mast cell-degranulating peptide from bee venom using the purified monoiodinated peptide.
1984,
Pubmed
Weller,
Electrophysiological and neurobiochemical evidence for the blockade of a potassium channel by dendrotoxin.
1985,
Pubmed