THE INTERACTION OF SEA-ANEMONE AND SCORPION NEUROTOXINS WITH TETRODOTOXIN-RESISTANT NA+ CHANNELS IN RAT MYOBLASTS - A COMPARISON WITH NA+ CHANNELS IN OTHER EXCITABLE AND NON-EXCITABLE CELLS

Abstract

The properties of interactions of several polypeptide neurotoxins isolated from sea anemone and scorpion venom with Na+ channels of rat myoblasts, chick myotubes, neuroblastoma cells, and fibroblasts were compared. Tetrodotoxin (TTX)-resistant Na+ channels appear to be much more sensitive to the action of sea anemone toxins than TTX-sensitive Na+ channel but have the same affinity for scorpion neurotoxins. This conclusion holds both for Na+ channels that can be activated electrically and for silent forms of Na+ channels. The sensitivity to sea anemone toxins of the different types of Na+ channels that have been studied suggests the existence of multiple forms of Na+ channels.