Linked Life Data

8917451

Source:http://linkedlifedata.com/resource/pubmed/id/8917451

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1997-1-9
pubmed:abstractText
A new toxin, BotIT2, with a unique mode of action on the isolated giant axon of the cockroach Periplaneta americana and DUM (dorsal unpaired median) neurons, has been purified from the venom of the scorpion Buthus occitanus tunetanus. Its structural, antigenic and pharmacological properties are compared to those of three other groups of neurotoxins found in Buthidae scorpion venoms. Like excitatory, depressant and alpha-type insect-selective neurotoxins, BotIT2 is toxic to insects, but shows the following common and distinctive characteristics. (a) As alpha-type toxins, BotIT2 lack strict selectivity to insects; they have measurable but low toxicity to mice. (b) As depressant toxins and unlike alpha-type toxins, BotIT2 is able to displace iodinated AaHIT from its binding sites in insect neuronal membranes. This indicates that the binding site for BotIT2 is identical, contiguous or in allosteric interaction with that of AaHIT and depressant toxins. (c) The BotIT2 amino acid sequence shows strong similarity to depressant toxins. However, unexpectedly, despite this high sequence similarity, BotIT2 shares moderate cross-antigenic reactivity with depressant toxins. (d) Voltage and current-clamp studies show that BotIT2 induces limited depolarization concomitantly with the development of depolarizing after potential, repetitive activity and later plateau potentials terminated by bursts. Under voltage-clamp conditions, BotIT2 specifically acts on Na+ channels by decreasing the peak Na+ current and by simultaneously inducing a new current with very slow activation/deactivation kinetics. The voltage dependence of this slow current is not significantly different from that of the control current. These observations indicate that BotIT2 chiefly modifies the kinetics of axonal and DUM neuronal membrane Na(+)-channel activation.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0014-2956
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
241
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
525-32
pubmed:dateRevised
2007-7-23
pubmed:meshHeading
pubmed:year
1996
pubmed:articleTitle
A new scorpion venom toxin paralytic to insects that affects Na+ channel activation. Purification, structure, antigenicity and mode of action.
pubmed:affiliation
Laboratoire des Venins et Toxins, Institut Pasteur de Tunis, Belvédère, Tunisia.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't