Details

Autor(en) / Beteiligte

• Loret, Erwann P.
• Sampieri, François
• Granier, Claude
• Miranda, Françis
• Rochat, Hervé

Titel

[28] - Scorpion Toxins Affecting Insects

Ist Teil von

• Methods in Neurosciences, 1992, Vol.8, p.381-395

Ort / Verlag

United States: Elsevier Science & Technology

Erscheinungsjahr

1992

Link zum Volltext

Quelle

ScienceDirect eBooks

Beschreibungen/Notizen

• This chapter provides an overview of the scorpion toxins affecting insects. The scorpion toxins specific for insects are divided into two different categories—contraction-inducing toxins, which causes rapid excitatory contraction paralysis in Sarcophaga argyrostoma fly larvae, and depressant toxins, which induces a slow depressant flaccid paralysis. Each type shows distinct electrophysiological effects when tested in current- and voltage-clamp conditions on an isolated axonal preparation of Periplaneta americana. However, both are capable of binding to a common site on the sodium channel of insects. The contraction-inducing toxins show electrophysiological effects in insects that are similar to those observed in the case of β-type toxins acting on mammals. The chapter additionally discusses a new type of anti-insect toxin, that is shown to bind to a different site on the sodium channel of insects. This toxin shows electrophysiological effects comparable to those described for α-type toxins acting on mammals. Thus, the sodium channels of insects and mammals can possess similar structures, leading to the division of the scorpion toxins into two types, α and β, according to their specific pharmacological and electrophysiological effects. The chapter focuses on techniques applied to such contraction inducing toxins isolated from venoms of North African scorpions. It also describes recent improvement in three areas—toxicity tests that can be used on insects, purification procedures for scorpion toxins active in insects, and a pharmacological assay.