Open channel block and open channel destabilization: contrasting effects of phenol, TEA+ and local anaesthetics on Kv1.1 K+ channels.
(1) Voltage-gated K+ channels are inhibited by a variety of clinical and experimental drugs. (2) Complex changes in channel gating suggest mechanisms in which drug affinity depends on channel state. (3) Here, we use the effects of external TEA+, two local anaesthetics (lidocaine and bupivacaine), and phenol on rat brain Kv1.1 K+ channels expressed in Xenopus oocytes to illustrate three mechanisms. (4) The open state has the highest affinity in the local anaesthetic model but the lowest in the phenol model, and while local anaesthetics simply block the open channel, phenol can produce a conducting but destabilized open state. (5) All states have equal affinity for external TEA+.
Elliott
A A
AA
Department of Anatomy and Physiology, University of Dundee, UK.
Harrold
J A
JA
Newman
J P
JP
Elliott
J R
JR
D000779:Anesthetics, Local / Q000494:pharmacology*; D000818:Animals; D004594:Electrophysiology; D015640:Ion Channel Gating / Q000187:drug effects; D051662:Kv1.1 Potassium Channel; D008012:Lidocaine / Q000494:pharmacology; D008564:Membrane Potentials / Q000502:physiology; D009865:Oocytes / Q000378:metabolism; D018408:Patch-Clamp Techniques; D019800:Phenol / Q000494:pharmacology*; D026902:Potassium Channel Blockers; D015221:Potassium Channels; D024642:Potassium Channels, Voltage-Gated; D051381:Rats; D019789:Tetraethylammonium / Q000494:pharmacology*; D014982:Xenopus laevis
D000779:Anesthetics, Local; D026902:Potassium Channel Blockers; D015221:Potassium Channels; D024642:Potassium Channels, Voltage-Gated; D051662:Kv1.1 Potassium Channel; D019800:Phenol; D019789:Tetraethylammonium; D008012:Lidocaine