Properties of the leakage current pathway: effects of the gadolinium ion on myelinated axons.
Voltage-clamp experiments on myelinated axons revealed that the trivalent gadoliniumion ion blocked the leakage current in a dose-dependent manner. The block showed 1:2 stoichiometry, and 50% reduction at 700 microM. Na+ and K+ currents were blocked at ten times lower concentration and showed 1:1 stoichiometry. Comparisons with biochemical studies suggest that the leakage current directly depends on a phospholipid pathway in contrast to the protein-channel dependent Na+ and K+ currents. The results may be explained by a leakage current pathway located at the interface between channel proteins and the lipid phase.
Elinder
F
F
Nobel Institute for Neurophysiology, Karolinska Institute, Stockholm, Sweden.
Arhem
P
P
D000818:Animals; D003864:Depression, Chemical; D004305:Dose-Response Relationship, Drug; D005682:Gadolinium / Q000494:pharmacology*; D007473:Ion Channels / Q000187:drug effects* / Q000378:metabolism; D008563:Membrane Lipids / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D009413:Nerve Fibers, Myelinated / Q000187:drug effects* / Q000502:physiology; D010713:Phosphatidylcholines / Q000378:metabolism; D011188:Potassium / Q000378:metabolism; D012584:Sciatic Nerve / Q000187:drug effects / Q000502:physiology; D012964:Sodium / Q000378:metabolism; D014982:Xenopus laevis
D007473:Ion Channels; D008563:Membrane Lipids; D008565:Membrane Proteins; D010713:Phosphatidylcholines; D012964:Sodium; D005682:Gadolinium; D011188:Potassium