Author/Editor		Šuput, Dušan; Bunc, Matjaž; Molgo, Jordi; Strupi-Šuput, Jerneja; Benoit, Evelyne
Title		Equinatoxins: from in vivo to cellular effects
Type		članek
Source		In: Goudey-Perriere F, Benoit E, Puiseux-Dao S, et al, editors. Envenimations, intoxinations.. Paris: Societe Francaise pour l'etude des toxines (SFET),
Publication year		2004
Volume		str. 153-60
Language		eng
Abstract		Equinatoxins (EgTs) are cytolytic basic peptides isolated from the sea anemone Actinia equina One of the mechanisms of their action is pore formation after insertion into lipid membrane bilayers and oligomerisation. The EqTs' cancentrations required for pore formation are several orders of magnitude higher than those causing significant effects in heart and skeletal muscle. Therefore, other mechanisms must also be involved in EqTs' toxicity. The effects of EqTs have been studied in vivo, on isolated heart and on vascular rings. The toxin effects on membrane conductance, ionic channels, intracellular Ca2+ activity, and on cell volume have also been studied, on several cell types, using laser scanning confocal or epi-fluorescence microscopy, microspectrofluorimetry, electrophysiology and electron paramagnetic resonance. Perfusion of lungs with 100 nM EqT II results in an effluent with less than 10 nM concentralion af ahe toxln which suggests that, after an intravenous injection, nearly all of the toxin molecules bind to the lungs. The lung perfusate still provokes cardiovascular effects identical to those caused by freshly prepared solutions containing I to 10 nMEqT II. This means that any substance that might have been released from the perfused lungs is not essential for the observed effects. A 100 nM concentration of EgT II causes an increase in the leakage conductance in al! of the cells studied. At lower cancentrations, a block of potassium currents, an incomplete block of sodium currents, and an activation of Ca2+-dependent potassium channels are observed. Different cells had distinet susceptibilities to the toxin, ranging fram 0.1 nM up to 100 nM The cells are swollen after a prolonged treatment with low concentrations of EqT II, or when 100 nM or higher concentrations of the toxin are used. (Abstract truncated at 2000 characters).
Descriptors		SEA ANEMONES CNIDARIAN VENOMS MEMBRANE LIPIDS MEMBRANE FLUIDITY PORINS CELL MEMBRANE PERMEABILITY MICROSCOPY, ELECTRON HEMOLYSIS HYPERKALEMIA HEART RATE