title: Potential-dependent effects of sea anemone toxins and scorpion venom on crayfish giant axon.
abstract: Effects of two kinds of sea anemone toxin (Parasicyonis actinostoloides and Anemonia sulcata) and scorpion venom (Leiurus quinquestriatus) on crayfish giant axons were examined electrophysiologically. All toxins acted on the axon in a similar manner to prolong the falling phase of the action potential. In all cases the development of toxicity was reduced when the nerve membrane was depolarized by a current injection. However, the ranges of membrane potential where the significant reduction in toxicity took place were different for each toxin. The action of Parasicyonis toxin was also suppressed by depolarization resulting from treatment of the axon with a neurotoxic alkaloid, veratridine. The mechanism of the potential-dependent toxin action is discussed with reference to the present data and relevant works by other investigators.
mesh_terms: D000818:Animals; D003400:Astacoidea; D001369:Axons / Q000187:drug effects*; D003064:Cnidarian Venoms / Q000494:pharmacology*; D066298:In Vitro Techniques; D008387:Marine Toxins / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects; D009467:Neuromuscular Depolarizing Agents; D012604:Scorpion Venoms / Q000494:pharmacology*; D012615:Sea Anemones; D013997:Time Factors; D014701:Veratridine / Q000494:pharmacology
chemical_list: D003064:Cnidarian Venoms; D008387:Marine Toxins; D009467:Neuromuscular Depolarizing Agents; D012604:Scorpion Venoms; C027605:parasicyonis toxin; D014701:Veratridine