Batrachotoxin and α-scorpion toxin stabilize the open state of single voltage-gated sodium channels

Michael O'Leary, B. K. Krueger

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

The combined effects of batrachotoxin (BTX) and either scorpion (Leiurus quinquestriatus quinquestriatus) venom (LqqV) or α-scorpion toxin (α-LqqTX) purified from LqqV on single voltage-gated Na channels were studied in planar lipid bilayers. In the presence of BTX, LqqV caused the channels to remain open at membrane potentials at least 50 mV more hyperpolarized than with BTX alone. α-LqqTX mimicked the effect of LqqV, suggesting that this toxin is the active component of the venom. LqqV did not significantly alter single-channel conductance, voltage-dependent block by saxitoxin, or voltage-dependent block by Ca2+, indicating that the venom preferentially affects gating rather than ion permeation. The results indicate that a cooperative interaction between α-LqqTX and BTX strongly favors the open state of the Na channel by causing a large hyperpolarizing shift in the voltage dependence of activation. This effect on activation gating is not predicted from the individual effects of the toxins.

Original languageEnglish (US)
Pages (from-to)789-795
Number of pages7
JournalMolecular Pharmacology
Volume36
Issue number5
StatePublished - Dec 22 1989

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Batrachotoxins
Voltage-Gated Sodium Channels
Scorpions
Venoms
Saxitoxin
Scorpion Venoms
Lipid Bilayers
Membrane Potentials
Ions

All Science Journal Classification (ASJC) codes

  • Molecular Medicine
  • Pharmacology

Cite this

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abstract = "The combined effects of batrachotoxin (BTX) and either scorpion (Leiurus quinquestriatus quinquestriatus) venom (LqqV) or α-scorpion toxin (α-LqqTX) purified from LqqV on single voltage-gated Na channels were studied in planar lipid bilayers. In the presence of BTX, LqqV caused the channels to remain open at membrane potentials at least 50 mV more hyperpolarized than with BTX alone. α-LqqTX mimicked the effect of LqqV, suggesting that this toxin is the active component of the venom. LqqV did not significantly alter single-channel conductance, voltage-dependent block by saxitoxin, or voltage-dependent block by Ca2+, indicating that the venom preferentially affects gating rather than ion permeation. The results indicate that a cooperative interaction between α-LqqTX and BTX strongly favors the open state of the Na channel by causing a large hyperpolarizing shift in the voltage dependence of activation. This effect on activation gating is not predicted from the individual effects of the toxins.",
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Batrachotoxin and α-scorpion toxin stabilize the open state of single voltage-gated sodium channels. / O'Leary, Michael; Krueger, B. K.

In: Molecular Pharmacology, Vol. 36, No. 5, 22.12.1989, p. 789-795.

Research output: Contribution to journalArticle

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AU - Krueger, B. K.

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