title: The presence of Na+ channels in myometrial smooth muscle cells is revealed by specific neurotoxins.
abstract: This paper shows the presence, in rat myometrial smooth muscles, of low affinity binding sites for tetrodotoxin with a K0.5 value of 2 microM. Electrophysiological experiments using both intact strips and single isolated myometrial cells in culture have shown that veratridine and sea anemone toxins reveal functional Na+ channels. The activity of these channels was blocked by tetrodotoxin (10 microM) or by removal of Na+ ions. Results presented here are the first direct demonstration of the existence in rat myometrium of Na+ channels of the tetrodotoxin-resistant type.
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D001667:Binding, Competitive; D003064:Cnidarian Venoms / Q000494:pharmacology; D005260:Female; D066298:In Vitro Techniques; D007473:Ion Channels / Q000032:analysis*; D009215:Myometrium / Q000378:metabolism*; D009498:Neurotoxins / Q000378:metabolism* / Q000494:pharmacology; D011247:Pregnancy; D051381:Rats; D012964:Sodium / Q000378:metabolism*; D013779:Tetrodotoxin / Q000378:metabolism; D014701:Veratridine / Q000494:pharmacology
chemical_list: D003064:Cnidarian Venoms; D007473:Ion Channels; D009498:Neurotoxins; D013779:Tetrodotoxin; C028800:toxin II (Anemonia sulcata); D014701:Veratridine; C035569:toxin V (Anemonia sulcata); D012964:Sodium