Multiple actions of arylalkylamine arthropod toxins on the N-methyl-D-aspartate receptor

S. D. Donevan, Michael A Rogawski

Research output: Contribution to journalArticle

25 Citations (Scopus)

Abstract

The effects of the arylalkyamine arthropod toxins argiotoxin 636 and philanthotoxin 343 were studied on N-methyl-D-aspartate receptor currents in cultured rat hippocampal neurons using whole-cell recording techniques. Argiotoxin 636 and philanthotoxin 343 blocked 10 μM N-methyl-D-aspartate (+10 μM glycine) currents in a concentration-dependent fashion (steady-state IC50 values, 0.9 and 56 μM, respectively). The onset and recovery from argiotoxin 636 block occurred slowly (forward and reverse rate constants, 7.5 × 103s-1 M-1 and 6.9 × 10-3s-1, respectively) whereas the philanthotoxin 343 block was more rapid (forward and reverse rate constants, 1.1 × 105s-1 M-1 and 0.1 s-1). A portion, but not all, of the block by the two toxins could be reversed by depolarization to positive holding potentials, indicating that there are voltage-dependent and non-voltage-dependent components of the block. The long-lasting argiotoxin 636 block at -60 mV occurred in a use-dependent fashion and could be substantially reduced by co-application with 10 mM Mg2+, providing evidence that the toxin has a channel blocking action. In contrast to the use dependence of the voltage-dependent argiotoxin 636 block, the non-voltage-dependent component of block (at +60 mV) did not require agonist gating of the channel. The non-voltage-dependent block by argiotoxin 636 was unaffected by increasing the glycine concentration, but was reversed by increasing the N-methyl-D-aspartate concentration, suggesting that the toxin may act as a competitive antagonist at the N-methyl-D-aspartate recognition site. This mechanism was further supported by the near identity of the time constant for argiotoxin 636 block with the time constant for agonist dissociation, irrespective of whether the rapidly dissociating agonist N-methyl-D-aspartate or the more slowly dissociating agonist glutamate was used. With high concentrations of N-methyl-D-aspartate (≥ 100 μM), argiotoxin 636 produced a potentiation of the peak N-methyl-D-aspartate response (at +60 mV) that was accompanied by a slowing in the rate of current desensitization and an increase in the affinity for glycine. We conclude that the arylalkylamine toxins antagonize N-methyl-D-aspartate receptor currents by two distinct mechanisms: use-dependent and voltage-dependent open channel block and competitive antagonism at the N-methyl-D-aspartate recognition site. In addition, argiotoxin 636 exerts a polyamine-like facilitation of N-methyl-D-aspartate receptor currents. This facilitation occurs via both the glycine-dependent and glycine-independent mechanisms, whereby spermine is known to potentiate N-methyl-D-aspartate receptor responses.

Original languageEnglish (US)
Pages (from-to)361-375
Number of pages15
JournalNeuroscience
Volume70
Issue number2
StatePublished - 1996
Externally publishedYes

Fingerprint

Arthropods
N-Methyl-D-Aspartate Receptors
N-Methylaspartate
Glycine
Excitatory Amino Acid Agonists
argiotoxin-636
Spermine
Polyamines
Patch-Clamp Techniques
Inhibitory Concentration 50
Neurons

Keywords

  • Argiotoxin 636
  • Channel block
  • Hippocampal neuron
  • Philanthotoxin 343
  • Polyamine
  • Whole-cell voltage-clamp recording

ASJC Scopus subject areas

  • Neuroscience(all)

Cite this

Multiple actions of arylalkylamine arthropod toxins on the N-methyl-D-aspartate receptor. / Donevan, S. D.; Rogawski, Michael A.

In: Neuroscience, Vol. 70, No. 2, 1996, p. 361-375.

Research output: Contribution to journalArticle

@article{2245139bc533403583a883ac682133e1,
title = "Multiple actions of arylalkylamine arthropod toxins on the N-methyl-D-aspartate receptor",
abstract = "The effects of the arylalkyamine arthropod toxins argiotoxin 636 and philanthotoxin 343 were studied on N-methyl-D-aspartate receptor currents in cultured rat hippocampal neurons using whole-cell recording techniques. Argiotoxin 636 and philanthotoxin 343 blocked 10 μM N-methyl-D-aspartate (+10 μM glycine) currents in a concentration-dependent fashion (steady-state IC50 values, 0.9 and 56 μM, respectively). The onset and recovery from argiotoxin 636 block occurred slowly (forward and reverse rate constants, 7.5 × 103s-1 M-1 and 6.9 × 10-3s-1, respectively) whereas the philanthotoxin 343 block was more rapid (forward and reverse rate constants, 1.1 × 105s-1 M-1 and 0.1 s-1). A portion, but not all, of the block by the two toxins could be reversed by depolarization to positive holding potentials, indicating that there are voltage-dependent and non-voltage-dependent components of the block. The long-lasting argiotoxin 636 block at -60 mV occurred in a use-dependent fashion and could be substantially reduced by co-application with 10 mM Mg2+, providing evidence that the toxin has a channel blocking action. In contrast to the use dependence of the voltage-dependent argiotoxin 636 block, the non-voltage-dependent component of block (at +60 mV) did not require agonist gating of the channel. The non-voltage-dependent block by argiotoxin 636 was unaffected by increasing the glycine concentration, but was reversed by increasing the N-methyl-D-aspartate concentration, suggesting that the toxin may act as a competitive antagonist at the N-methyl-D-aspartate recognition site. This mechanism was further supported by the near identity of the time constant for argiotoxin 636 block with the time constant for agonist dissociation, irrespective of whether the rapidly dissociating agonist N-methyl-D-aspartate or the more slowly dissociating agonist glutamate was used. With high concentrations of N-methyl-D-aspartate (≥ 100 μM), argiotoxin 636 produced a potentiation of the peak N-methyl-D-aspartate response (at +60 mV) that was accompanied by a slowing in the rate of current desensitization and an increase in the affinity for glycine. We conclude that the arylalkylamine toxins antagonize N-methyl-D-aspartate receptor currents by two distinct mechanisms: use-dependent and voltage-dependent open channel block and competitive antagonism at the N-methyl-D-aspartate recognition site. In addition, argiotoxin 636 exerts a polyamine-like facilitation of N-methyl-D-aspartate receptor currents. This facilitation occurs via both the glycine-dependent and glycine-independent mechanisms, whereby spermine is known to potentiate N-methyl-D-aspartate receptor responses.",
keywords = "Argiotoxin 636, Channel block, Hippocampal neuron, Philanthotoxin 343, Polyamine, Whole-cell voltage-clamp recording",
author = "Donevan, {S. D.} and Rogawski, {Michael A}",
year = "1996",
language = "English (US)",
volume = "70",
pages = "361--375",
journal = "Neuroscience",
issn = "0306-4522",
publisher = "Elsevier Limited",
number = "2",

}

TY - JOUR

T1 - Multiple actions of arylalkylamine arthropod toxins on the N-methyl-D-aspartate receptor

AU - Donevan, S. D.

AU - Rogawski, Michael A

PY - 1996

Y1 - 1996

N2 - The effects of the arylalkyamine arthropod toxins argiotoxin 636 and philanthotoxin 343 were studied on N-methyl-D-aspartate receptor currents in cultured rat hippocampal neurons using whole-cell recording techniques. Argiotoxin 636 and philanthotoxin 343 blocked 10 μM N-methyl-D-aspartate (+10 μM glycine) currents in a concentration-dependent fashion (steady-state IC50 values, 0.9 and 56 μM, respectively). The onset and recovery from argiotoxin 636 block occurred slowly (forward and reverse rate constants, 7.5 × 103s-1 M-1 and 6.9 × 10-3s-1, respectively) whereas the philanthotoxin 343 block was more rapid (forward and reverse rate constants, 1.1 × 105s-1 M-1 and 0.1 s-1). A portion, but not all, of the block by the two toxins could be reversed by depolarization to positive holding potentials, indicating that there are voltage-dependent and non-voltage-dependent components of the block. The long-lasting argiotoxin 636 block at -60 mV occurred in a use-dependent fashion and could be substantially reduced by co-application with 10 mM Mg2+, providing evidence that the toxin has a channel blocking action. In contrast to the use dependence of the voltage-dependent argiotoxin 636 block, the non-voltage-dependent component of block (at +60 mV) did not require agonist gating of the channel. The non-voltage-dependent block by argiotoxin 636 was unaffected by increasing the glycine concentration, but was reversed by increasing the N-methyl-D-aspartate concentration, suggesting that the toxin may act as a competitive antagonist at the N-methyl-D-aspartate recognition site. This mechanism was further supported by the near identity of the time constant for argiotoxin 636 block with the time constant for agonist dissociation, irrespective of whether the rapidly dissociating agonist N-methyl-D-aspartate or the more slowly dissociating agonist glutamate was used. With high concentrations of N-methyl-D-aspartate (≥ 100 μM), argiotoxin 636 produced a potentiation of the peak N-methyl-D-aspartate response (at +60 mV) that was accompanied by a slowing in the rate of current desensitization and an increase in the affinity for glycine. We conclude that the arylalkylamine toxins antagonize N-methyl-D-aspartate receptor currents by two distinct mechanisms: use-dependent and voltage-dependent open channel block and competitive antagonism at the N-methyl-D-aspartate recognition site. In addition, argiotoxin 636 exerts a polyamine-like facilitation of N-methyl-D-aspartate receptor currents. This facilitation occurs via both the glycine-dependent and glycine-independent mechanisms, whereby spermine is known to potentiate N-methyl-D-aspartate receptor responses.

AB - The effects of the arylalkyamine arthropod toxins argiotoxin 636 and philanthotoxin 343 were studied on N-methyl-D-aspartate receptor currents in cultured rat hippocampal neurons using whole-cell recording techniques. Argiotoxin 636 and philanthotoxin 343 blocked 10 μM N-methyl-D-aspartate (+10 μM glycine) currents in a concentration-dependent fashion (steady-state IC50 values, 0.9 and 56 μM, respectively). The onset and recovery from argiotoxin 636 block occurred slowly (forward and reverse rate constants, 7.5 × 103s-1 M-1 and 6.9 × 10-3s-1, respectively) whereas the philanthotoxin 343 block was more rapid (forward and reverse rate constants, 1.1 × 105s-1 M-1 and 0.1 s-1). A portion, but not all, of the block by the two toxins could be reversed by depolarization to positive holding potentials, indicating that there are voltage-dependent and non-voltage-dependent components of the block. The long-lasting argiotoxin 636 block at -60 mV occurred in a use-dependent fashion and could be substantially reduced by co-application with 10 mM Mg2+, providing evidence that the toxin has a channel blocking action. In contrast to the use dependence of the voltage-dependent argiotoxin 636 block, the non-voltage-dependent component of block (at +60 mV) did not require agonist gating of the channel. The non-voltage-dependent block by argiotoxin 636 was unaffected by increasing the glycine concentration, but was reversed by increasing the N-methyl-D-aspartate concentration, suggesting that the toxin may act as a competitive antagonist at the N-methyl-D-aspartate recognition site. This mechanism was further supported by the near identity of the time constant for argiotoxin 636 block with the time constant for agonist dissociation, irrespective of whether the rapidly dissociating agonist N-methyl-D-aspartate or the more slowly dissociating agonist glutamate was used. With high concentrations of N-methyl-D-aspartate (≥ 100 μM), argiotoxin 636 produced a potentiation of the peak N-methyl-D-aspartate response (at +60 mV) that was accompanied by a slowing in the rate of current desensitization and an increase in the affinity for glycine. We conclude that the arylalkylamine toxins antagonize N-methyl-D-aspartate receptor currents by two distinct mechanisms: use-dependent and voltage-dependent open channel block and competitive antagonism at the N-methyl-D-aspartate recognition site. In addition, argiotoxin 636 exerts a polyamine-like facilitation of N-methyl-D-aspartate receptor currents. This facilitation occurs via both the glycine-dependent and glycine-independent mechanisms, whereby spermine is known to potentiate N-methyl-D-aspartate receptor responses.

KW - Argiotoxin 636

KW - Channel block

KW - Hippocampal neuron

KW - Philanthotoxin 343

KW - Polyamine

KW - Whole-cell voltage-clamp recording

UR - http://www.scopus.com/inward/record.url?scp=0029656272&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0029656272&partnerID=8YFLogxK

M3 - Article

VL - 70

SP - 361

EP - 375

JO - Neuroscience

JF - Neuroscience

SN - 0306-4522

IS - 2

ER -