title: Insensitivity of activation delays in potassium and sodium channels to heavy water in Myxicola giant axons.
abstract: Substitution of heavy water (D2O) for H2O slows the Na+ and K+ currents in Myxicola giant axons by 40-50% at 5 degrees C. In contrast, the delays in Na+ K+ activation which can be produced by hyperpolarizing pre-pulses are not affected by solvent substitution. We suggest that in the cascade of transitions leading to the opening of Na+ and K+ channels, D2O affects only the final step that establishes the aqueous pore across the membrane.
mesh_terms: D000818:Animals; D001369:Axons / Q000378:metabolism / Q000502:physiology*; D003903:Deuterium / Q000378:metabolism*; D066298:In Vitro Techniques; D007473:Ion Channels / Q000378:metabolism*; D008564:Membrane Potentials; D011077:Polychaeta; D011188:Potassium / Q000378:metabolism* / Q000502:physiology; D012964:Sodium / Q000378:metabolism* / Q000502:physiology
chemical_list: D007473:Ion Channels; D012964:Sodium; D003903:Deuterium; D011188:Potassium