Effects of toxin isolated from the sea anemone Bolocera tuediae on electrical properties of isolated rat skeletal muscle and cultured myotubes.
Electrophysiological effects of a polypeptide toxin isolated from the sea anemone Bolocera tuediae (BTTX II) on isolated fast and slow rat skeletal muscle and on cultured rat myotubes are described in this paper. Nanomolar concentrations of BTTX II cause a concentration-dependent depolarization. This effect is prevented by the presence of tetrodotoxin. Action potential duration is prolonged in all preparations investigated, with the fast muscle being the least sensitive. The positive overshoot and the maximum rate of rise of the action potential is decreased by BTTX II. Cultured myotubes which are less susceptible to the sodium channel blocking activity of tetrodotoxin have the highest sensitivity to all actions of BTTX II. It is further shown that the proportion of spontaneously contracting myotubes is diminished and the frequency of contractions is increased by the toxin. The effects of Bolocera tuediae toxin II resemble those observed with Anemonia sulcata toxin II on mammalian skeletal muscle. From the results it is concluded, that BTTX II may interfere with both the activation and inactivation of sodium channels of the muscle membrane.
Tesseraux
I
I
Abteilung Toxikologie, Klinikum der Universität Kiel, Federal Republic of Germany.
Gülden
M
M
Schumann
G
G
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D002478:Cells, Cultured; D003063:Cnidaria / Q000502:physiology*; D003064:Cnidarian Venoms / Q000633:toxicity*; D004594:Electrophysiology; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D008870:Microtubules / Q000187:drug effects; D009119:Muscle Contraction / Q000187:drug effects; D009132:Muscles / Q000503:physiopathology* / Q000648:ultrastructure; D051381:Rats; D011919:Rats, Inbred Strains; D012615:Sea Anemones / Q000502:physiology*
D003064:Cnidarian Venoms