Fast K channels are more sensitive to riluzole than slow K channels in myelinated nerve fibre.
The effects of 1-500 microM riluzole, a novel psychotropic agent, were studied on the nodal K current of isolated nerve fibres of the frog. When added to the external solution, the substance rapidly and reversibly inhibited slow, fast 1 and fast 2 K components of the tail K current. The concentrations of riluzole inducing half maximum reduction of slow, fast 1 and fast 2 K conductances were 413 microM, 24 microM and 21 microM respectively. It is concluded that the substance is about 20 times more effective in blocking fast than slow K channels.
Benoit
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Laboratoire de Physiologie Cellulaire, URA CNRS, Université Paris Sud, Orsay, France.
Escande
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D000777:Anesthetics / Q000494:pharmacology*; D000818:Animals; D066298:In Vitro Techniques; D009413:Nerve Fibers, Myelinated / Q000187:drug effects / Q000378:metabolism*; D015221:Potassium Channels / Q000187:drug effects*; D011189:Potassium Chloride / Q000494:pharmacology; D011619:Psychotropic Drugs / Q000494:pharmacology*; D011893:Rana esculenta; D011901:Ranvier's Nodes / Q000187:drug effects / Q000378:metabolism; D019782:Riluzole; D012584:Sciatic Nerve / Q000166:cytology / Q000187:drug effects; D013844:Thiazoles / Q000494:pharmacology*
D000777:Anesthetics; D015221:Potassium Channels; D011619:Psychotropic Drugs; D013844:Thiazoles; D011189:Potassium Chloride; D019782:Riluzole