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Electrophysiological and neurobiochemical evidence for the blockade of a potassium channel by dendrotoxin

  • U. Weller
  • U. Bernhardt
  • D. Siemen
  • F. Dreyer
  • W. Vogel
  • E. Habermann
Article

Summary

The effects of dendrotoxin (DTX), a toxic peptide from Dendroaspis angusticeps venom, were studied electrophysiologically on peripheral frog nerve fibres, and biochemically on large synaptosomes from rat brain.
  1. 1.

    On nerve fibres, DTX reduced the amplitude and prolonged the duration of the action potential; even at 0.1 nmol/l DTX produced significant effects. Maximum block of potassium currents occurred at about 30 nmol/l. Turning on of the remaining current was slowed. Reversibility was incomplete. The reduction of potassium currents was between 31% and 85% at 85 nmol/l DTX (n=8). The remainder appeared to be resistant to DTX. Sodium channels were not affected.

     
  2. 2.

    On large synaptosomes DTX (above 1 nmol/l) produced a slight depolarization, indicated by an outward shift of the lipophilic cation tetraphenylphosphonium, and promoted the release of radioactivity after preloading with [3H] GABA. DTX had similar potency but lower efficacy in this respect than sea anemone toxin II (ATX II). In contrast to the effects of ATX II, those due to DTX were only partially inhibited by tetrodotoxin. The actions of 4-aminopyridine resembled those of DTX, but the latter was about 500 times more potent.

     

The electrophysiological data provide direct evidence for blockade of a potassium channel by DTX. This action is sufficient to explain the biochemical observations, although additional effects on synaptosomes cannot be excluded.

Key words

Dendrotoxin Potassium channel Nerve fibre Depolarization GABA 

Abbreviations

AOAA

aminooxy acetic acid

ATX II

Anemonia sulcata toxin II

BES

N,N-bis-(2-hydroxyethyl)-2-amino ethane sulfonic acid

DTX

dendrotoxin

EGTA

ethyleneglycol-bis(β-aminoethylether) N,N′-tetraacetic acid

GABA

γ-amino-n-butyric acid

HEPES

N-2-hydroxyethylpiperazine-N′-2-ethane sulfonic acid

KRH

Krebs-Ringer-Hepes

TEA

tetraethylammonium chloride

TPP

tetraphenylphosphonium bromide

TTX

tetrodotoxin

4-AP

4-aminopyridine

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References

  1. Albus U, Habermann E (1983) Tetanus toxin inhibits the evoked outflow of an inhibitory (GABA) and an excitatory (d-aspartate) amino acid from particulate brain cortex. Toxicon 21:97–110Google Scholar
  2. Barrett JC, Harvey AL (1979) Effects of the venom of the green mamba, Dendroaspis angusticeps on skeletal muscle and neuromuscular transmission. Brit J Pharmacol 67:199–205Google Scholar
  3. Bigalke H, Ahnert-Hilger G, Habermann E (1981) Tetanus toxin and botulinum A toxin inhibit acetylcholine release from but not calcium uptake into brain tissue. Naunyn-Schmiedeberg's Arch Pharmacol 316:143–148Google Scholar
  4. Carbone E, Wanke E, Prestipino G, Possani LD, Maelicke A (1982) Selective blockage of voltage-dependent K+-channels by a novel scorpion toxin. Nature 296:90–91Google Scholar
  5. Docherty RJ, Dolly JO, Halliwell JV, Othman I (1983) Excitatory effects of dendrotoxin on the hippocampus in vitro. J Physiol (Lond) 336:58P-59PGoogle Scholar
  6. Dolly JO, Halliwell JV, Black JD, Williams RS, Pelchen-Matthews A, Breeze AL, Mehraban F, Othman JB, Black AR (1984) Botulinum neurotoxin and dendrotoxin as probes for studies on transmitter release. J Physiol, Paris, 79:280–303Google Scholar
  7. Habermann E (1983) Action and binding of palytoxin, as studied with brain membranes. Naunyn-Schmiedeberg's Arch Pharmacol 323:269–275Google Scholar
  8. Habermann E (1984) Apamin. Pharmacol Ther 25:255–270Google Scholar
  9. Habermann E, Reiz KG (1965) Ein neues Verfahren zur Gewinnung der Komponenten von Bienengift, insbesondere des zentralwirksamen Peptids Apamin. Biochem Z 341:451–466Google Scholar
  10. Harvey AL, Gage PW (1981) Increase of evoked released of acetylcholine at the neuromuscular junction by a fraction from the venom of the eastern green mamba snake (Dendroaspis angusticeps). Toxicon 19:373–381Google Scholar
  11. Harvey AL, Karlsson E (1980) Dendrotoxin from the venom of the green mamba, Dendroaspis angusticeps. A neurotoxin that enhances acetylcholine release of neuromuscular junctions. Naunyn-Schmiedeberg's Arch Pharmacol 312:1–6Google Scholar
  12. Harvey AL, Karlsson E (1982) Protease inhibitor homologues from mamba venoms: Facilitation of acetylcholine release and interactions with prejunctional blocking toxins Brit J Pharmac 77:153–161Google Scholar
  13. Harvey AL, Karlsson E (1984) Polypeptide neurotoxins from mamba venoms that facilitate transmitter release. Trends in Pharmacol Sci 4:71–72Google Scholar
  14. Howard BD, Gundersen CB (1980) Effects and mechanisms of polypeptide neurotoxins that act presynaptically. Ann Rev Pharmacol Toxicol 20:307–336Google Scholar
  15. Kelly P, Cotman CW, Gentry C, Nicolson GL (1976) Distribution and mobility of lectin receptors on synaptic membranes of identified neurons in the central nervous system. J Cell Biol 71:487–496Google Scholar
  16. Lichtshtein P, Kaback HR, Blume AJ (1979) Use of lipophilic cation for determination of membrane potential in neuroblastomaglioma hybrid cell suspensions. Proc Natl Acad Sci USA 76:650–654Google Scholar
  17. Mehraban F, Breeze AL, Dolly JO (1984) Identification by crosslinking of a neuronal acceptor protein for dendrotoxin, a convulsant polypeptide. FEBS Lett 174:116–122Google Scholar
  18. Nonner W (1969) A new voltage clamp method for Ranvier nodes. Pflügers Arch 309:176–192Google Scholar
  19. Othman IB, Spokes JW, Dolly JO (1982) Preparation of neurotoxic [3H]-β-bungarotoxin: Demonstration of saturable binding to brain synapses and its inhibition by toxin I. Europ J Biochem 128:267–276Google Scholar
  20. Ramos S, Grollman EF, Lazo PS, Dyer SA, Habig WH, Hardegree MC, Kaback HR, Kohn LD (1979) Effect of tetanus toxin on the accumulation of the permeant lipophilic cation tetraphenyl-phosphonium by guinea pig brain synaptosomes. Proc Natl Acad Sci USA 76:4783–4787Google Scholar
  21. Rehm H, Betz H (1984) Solubilization and characterization of the β-bungarotoxin-binding protein of chick brain membranes. J Biol Chem 259:6865–6869Google Scholar
  22. Schwarz JR, Ulbricht W, Wagner H-H (1973) The rate of action of tetrodotoxin on myelinated nerve fibres of Xenopus laevis and Rana esculenta. J Physiol (Lond) 233:167–194Google Scholar
  23. Siemen D, Vogel W (1983) Tetrodotoxin interferes with the reaction of scorpion toxin Buthus tamulus at the sodium channel of the excitable membrane. Pflügers Arch 397:306–311Google Scholar
  24. Sihra TS, Scott IG, Nicholls DG (1984) Ionophore A 23187, verapamil, protonophores and veratridine influence the release of γ-aminobutyric acid from synaptosomes by modulation of plasma membrane potential rather than the cytosolic calcium. J Neurochem 43:1624–1630Google Scholar

Copyright information

© Springer-Verlag 1985

Authors and Affiliations

  • U. Weller
    • 1
  • U. Bernhardt
    • 2
  • D. Siemen
    • 2
  • F. Dreyer
    • 1
  • W. Vogel
    • 2
  • E. Habermann
    • 1
  1. 1.Rudolf-Buchheim-Institut für PharmakologieJustus-Liebig-Universität GießenGießenFederal Republic of Germany
  2. 2.Physiologisches InstitutJustus-Liebig-Universität GießenGießenFederal Republic of Germany

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