The endogenous pentapeptide QYNAD induces acute conduction block in the isolated rat sciatic nerve.
Reversible block of sodium channels by endogenous substances was claimed to account for the fast relapses and remissions seen in demyelinating autoimmune disorders. The pentapeptide QYNAD, isolated from the cerebrospinal fluid from patients with multiple sclerosis (MS), blocked Na+ channels in various types of cultured cells. We show that 100 microM QYNAD bath-applied to isolated rat sciatic nerve causes the amplitude and area of the compound nerve action potential to decrease by 30-40%, while the latency increases. Wash-out reverses the changes in part. This suggests that QYNAD may indeed contribute to the fast symptom changes in MS and related diseases.
Weber
Frank
F
German Air Force Institute of Aviation Medicine, Department of Neurology, P.O. Box 1264 KFL, 82242 Fürstenfeldbruck, Germany.
Rüdel
Reinhardt
R
Aulkemeyer
Peter
P
Brinkmeier
Heinrich
H
D000200:Action Potentials / Q000187:drug effects / Q000502:physiology*; D000779:Anesthetics, Local / Q000494:pharmacology; D000818:Animals; D004558:Electric Stimulation; D005260:Female; D008012:Lidocaine / Q000494:pharmacology; D020529:Multiple Sclerosis, Relapsing-Remitting / Q000378:metabolism* / Q000503:physiopathology; D009431:Neural Conduction / Q000187:drug effects / Q000502:physiology*; D009842:Oligopeptides / Q000378:metabolism* / Q000494:pharmacology; D010455:Peptides / Q000378:metabolism* / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology*; D012584:Sciatic Nerve / Q000187:drug effects / Q000378:metabolism* / Q000503:physiopathology; D026941:Sodium Channel Blockers; D015222:Sodium Channels / Q000378:metabolism*
D000779:Anesthetics, Local; D009842:Oligopeptides; D010455:Peptides; D026941:Sodium Channel Blockers; D015222:Sodium Channels; C450845:pentapeptide QYNAD; D008012:Lidocaine