Effects of 2 phospholipases a2 from the australian king brown snake (pseudechis-australis) on isolated nerve-muscle preparations

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Abstract

The venom from P. australis is lethal and has phospholipase A activity. Two phospholipases A (Pa-ll and Pa-13) have been isolated; Pa-ll has an LDs0 value of 0.23 ~g/g (i.v.) in mice, whereas Pa-13 was not lethal at 7.4 ~g/g (Nishlda et aI., 1985). In chick biventer cervlcis, Pa-11 (2-20 ~g/ml) reduced responses to indirect stimulation after a prolonged contracture and a transient increase in twitch height. Pa-ll at i0 ~g/ml reduced responses to acetylchollne, carbachol and KCI. At 2 ~g/ml, 50% twitch block was observed after 500 minutes and at 5-20 ~g/ml, complete block was observed after 300 minutes. Pa-13 (at 20 ~g/ml) had no effect on acetylcholine, carbachol and KCl responses, but at 30-40 ~g/ml, these responses were reduced. Neuromuscular block was not observed after 300 minutes at 20-40 ~g/ml. On addition of Pa-13, an immediate, brief contracture occurred. Pa-ll and Pa-13 were tested on mouse hemldlaphragm nerve-muscle preparations stimulated directly and indirectly. The onset of block with Pa-ll was similar at different concentrations, with no lag period. Initially, the blocking rates of the indirect and direct responses were similar but eventually the indirect response was blocked at a faster rate. Only the highest concentration tested (i0 ~g/ml) abolished the direct response. Addition of Pa-ll was followed by muscle contracture and a transient increase in twitch height. Pa-13 (10-20 ~g/ml) caused no increase in indirectly evoked twitches. Contracture occurs at the same time as spontaneous twitching. Neuromuscular block was not observed after 300 minutes.
Original languageEnglish
Pages (from-to)606-606
Number of pages0
JournalToxicon
Volume23
Issue number4
DOIs
Publication statusPublished - 1985

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Colubridae
Neuromuscular Junction
Phospholipases A2
Muscle
Contracture
Neuromuscular Blockade
Phospholipases A
Carbachol
Venoms
Acetylcholine
Pseudechis venom
Muscles

Keywords

  • Pseudechls australls
  • phospholipase
  • neuromuscular block

Cite this

@article{0dc7375801374c919642b2cfdd30e2cc,
title = "Effects of 2 phospholipases a2 from the australian king brown snake (pseudechis-australis) on isolated nerve-muscle preparations",
abstract = "The venom from P. australis is lethal and has phospholipase A activity. Two phospholipases A (Pa-ll and Pa-13) have been isolated; Pa-ll has an LDs0 value of 0.23 ~g/g (i.v.) in mice, whereas Pa-13 was not lethal at 7.4 ~g/g (Nishlda et aI., 1985). In chick biventer cervlcis, Pa-11 (2-20 ~g/ml) reduced responses to indirect stimulation after a prolonged contracture and a transient increase in twitch height. Pa-ll at i0 ~g/ml reduced responses to acetylchollne, carbachol and KCI. At 2 ~g/ml, 50{\%} twitch block was observed after 500 minutes and at 5-20 ~g/ml, complete block was observed after 300 minutes. Pa-13 (at 20 ~g/ml) had no effect on acetylcholine, carbachol and KCl responses, but at 30-40 ~g/ml, these responses were reduced. Neuromuscular block was not observed after 300 minutes at 20-40 ~g/ml. On addition of Pa-13, an immediate, brief contracture occurred. Pa-ll and Pa-13 were tested on mouse hemldlaphragm nerve-muscle preparations stimulated directly and indirectly. The onset of block with Pa-ll was similar at different concentrations, with no lag period. Initially, the blocking rates of the indirect and direct responses were similar but eventually the indirect response was blocked at a faster rate. Only the highest concentration tested (i0 ~g/ml) abolished the direct response. Addition of Pa-ll was followed by muscle contracture and a transient increase in twitch height. Pa-13 (10-20 ~g/ml) caused no increase in indirectly evoked twitches. Contracture occurs at the same time as spontaneous twitching. Neuromuscular block was not observed after 300 minutes.",
keywords = "Pseudechls australls, phospholipase, neuromuscular block",
author = "E.G. Rowan and A.L. Harvey and N. Tamiya",
year = "1985",
doi = "10.1016/0041-0101(85)90312-5",
language = "English",
volume = "23",
pages = "606--606",
journal = "Toxicon",
issn = "0041-0101",
number = "4",

}

TY - JOUR

T1 - Effects of 2 phospholipases a2 from the australian king brown snake (pseudechis-australis) on isolated nerve-muscle preparations

AU - Rowan, E.G.

AU - Harvey, A.L.

AU - Tamiya, N.

PY - 1985

Y1 - 1985

N2 - The venom from P. australis is lethal and has phospholipase A activity. Two phospholipases A (Pa-ll and Pa-13) have been isolated; Pa-ll has an LDs0 value of 0.23 ~g/g (i.v.) in mice, whereas Pa-13 was not lethal at 7.4 ~g/g (Nishlda et aI., 1985). In chick biventer cervlcis, Pa-11 (2-20 ~g/ml) reduced responses to indirect stimulation after a prolonged contracture and a transient increase in twitch height. Pa-ll at i0 ~g/ml reduced responses to acetylchollne, carbachol and KCI. At 2 ~g/ml, 50% twitch block was observed after 500 minutes and at 5-20 ~g/ml, complete block was observed after 300 minutes. Pa-13 (at 20 ~g/ml) had no effect on acetylcholine, carbachol and KCl responses, but at 30-40 ~g/ml, these responses were reduced. Neuromuscular block was not observed after 300 minutes at 20-40 ~g/ml. On addition of Pa-13, an immediate, brief contracture occurred. Pa-ll and Pa-13 were tested on mouse hemldlaphragm nerve-muscle preparations stimulated directly and indirectly. The onset of block with Pa-ll was similar at different concentrations, with no lag period. Initially, the blocking rates of the indirect and direct responses were similar but eventually the indirect response was blocked at a faster rate. Only the highest concentration tested (i0 ~g/ml) abolished the direct response. Addition of Pa-ll was followed by muscle contracture and a transient increase in twitch height. Pa-13 (10-20 ~g/ml) caused no increase in indirectly evoked twitches. Contracture occurs at the same time as spontaneous twitching. Neuromuscular block was not observed after 300 minutes.

AB - The venom from P. australis is lethal and has phospholipase A activity. Two phospholipases A (Pa-ll and Pa-13) have been isolated; Pa-ll has an LDs0 value of 0.23 ~g/g (i.v.) in mice, whereas Pa-13 was not lethal at 7.4 ~g/g (Nishlda et aI., 1985). In chick biventer cervlcis, Pa-11 (2-20 ~g/ml) reduced responses to indirect stimulation after a prolonged contracture and a transient increase in twitch height. Pa-ll at i0 ~g/ml reduced responses to acetylchollne, carbachol and KCI. At 2 ~g/ml, 50% twitch block was observed after 500 minutes and at 5-20 ~g/ml, complete block was observed after 300 minutes. Pa-13 (at 20 ~g/ml) had no effect on acetylcholine, carbachol and KCl responses, but at 30-40 ~g/ml, these responses were reduced. Neuromuscular block was not observed after 300 minutes at 20-40 ~g/ml. On addition of Pa-13, an immediate, brief contracture occurred. Pa-ll and Pa-13 were tested on mouse hemldlaphragm nerve-muscle preparations stimulated directly and indirectly. The onset of block with Pa-ll was similar at different concentrations, with no lag period. Initially, the blocking rates of the indirect and direct responses were similar but eventually the indirect response was blocked at a faster rate. Only the highest concentration tested (i0 ~g/ml) abolished the direct response. Addition of Pa-ll was followed by muscle contracture and a transient increase in twitch height. Pa-13 (10-20 ~g/ml) caused no increase in indirectly evoked twitches. Contracture occurs at the same time as spontaneous twitching. Neuromuscular block was not observed after 300 minutes.

KW - Pseudechls australls

KW - phospholipase

KW - neuromuscular block

UR - http://dx.doi.org/10.1016/0041-0101(85)90312-5

U2 - 10.1016/0041-0101(85)90312-5

DO - 10.1016/0041-0101(85)90312-5

M3 - Article

VL - 23

SP - 606

EP - 606

JO - Toxicon

JF - Toxicon

SN - 0041-0101

IS - 4

ER -