C fiber generates a slow Na+ spike in the frog sciatic nerve.
The present study was carried out to examine the properties of A and C fibers in the bullfrog sciatic nerves by applying several agents through perfusing solutions between stimulating and recording electrodes. The compound action potentials (CAPs) of A beta and A delta fibers were tetrodotoxin (TTX)-sensitive and were abolished in Na(+)-free solution. However, C fiber CAP was TTX-insensitive although CAP disappeared in Na(+)-free solution. Moreover, C fiber CAP was not blocked by Ca2+ channel blockers and its chronaxy (2 ms) and conduction velocity (0.70 m/s) indicate that the time constant of C fiber CAP is relatively large (2.88 ms). These suggest that a slow Na+ channel, which is TTX-resistant, contributes to C fiber action potentials.
Kobayashi
J
J
Department of Prosthetic Dentistry I, Faculty of Dentistry, Kyushu University, Fukuoka, Japan.
Ohta
M
M
Terada
Y
Y
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D002104:Cadmium / Q000494:pharmacology; D004558:Electric Stimulation; D066298:In Vitro Techniques; D009412:Nerve Fibers / Q000187:drug effects / Q000502:physiology*; D009413:Nerve Fibers, Myelinated / Q000187:drug effects / Q000378:metabolism; D009431:Neural Conduction / Q000187:drug effects; D011892:Rana catesbeiana; D012584:Sciatic Nerve / Q000166:cytology / Q000502:physiology*; D015222:Sodium Channels / Q000187:drug effects / Q000502:physiology*; D013779:Tetrodotoxin / Q000494:pharmacology
D015222:Sodium Channels; D002104:Cadmium; D013779:Tetrodotoxin