All or none block of single Na+ channels by tetrodotoxin.
The effects of tetrodotoxin on single Na+-channel currents recorded from excised patches of neuroblastoma cells were examined. Tetrodotoxin was found to cause a dose-dependent reduction in the frequency at which Na+ channels conduct during a series of depolarizations. Surviving conducting states had normal open times and current amplitudes. These effects could be explained by a model which includes initial binding of tetrodotoxin to a closed state of the channel with stable, complete block during the time the channel would normally be gated open.
Quandt
F N
FN
Yeh
J Z
JZ
Narahashi
T
T
D002460:Cell Line; D007473:Ion Channels / Q000187:drug effects*; D008564:Membrane Potentials; D008959:Models, Neurological; D009447:Neuroblastoma; D012530:Saxitoxin / Q000494:pharmacology; D012964:Sodium / Q000378:metabolism*; D013779:Tetrodotoxin / Q000494:pharmacology*
D007473:Ion Channels; D012530:Saxitoxin; D013779:Tetrodotoxin; D012964:Sodium