Slowed inactivation at positive potentials in a rat axonal K+ channel is not due to preferential closed-state inactivation

Title:

Slowed inactivation at positive potentials in a rat axonal K+ channel is not due to preferential closed-state inactivation

Creator:

Babes, A., Lörinczi, E., Ristoiu, V., Flonta, M.-L., and Reid, G.

Identifier:

https://cdk.lib.cas.cz/client/handle/uuid:7eff340b-d7f4-4c14-af3e-2621df3c53bd
uuid:7eff340b-d7f4-4c14-af3e-2621df3c53bd
issn:0862-8408

Subject:

Fyziologie člověka a srovnávací fyziologie, fyziologie, physiology, potassim channel, inactivation, axon, rat, 14, and 612

Type:

article, články, model:article, and TEXT

Format:

print, bez média, and svazek

Description:

We have investigated slow inactivation in a rat axonal K+ channel, the I channel. Using voltage steps to potentials between -70 mV and +80 mV, from a holding potential of -100 mV, we observed a marked slowing of inactivation at positive potentials: the time constant was 4.5±0.4 s at -40 mV (mean ± S.E.M.), increasing to 14.7±2.0 s at +40 mV. Slowed inactivation at positive potentials is not consistent with published descriptions of C-type inactivation, but can be explained by models in which inactivation is preferentially from closed states (which have been developed for Kv2.1 and some Ca2+ channels). We tested two predictions of preferential closed-state models: inactivation should be more rapid during a train of brief pulses than during a long pulse to the same potential, and the cumulative inactivation measured with paired pulses should be greater than the inactivation at the same time during a continuous pulse. The I channel does not behave according to these predictions, indicating that preferential closed-state inactivation does not explain the slowing of inactivation we observe at positive potentials. Inactivation of the I channel therefore differs both from C-type inactivation, as presently understood, and from the inactivation of Kv2.1., A. Babes, E. Lörinczi, V. Ristoiu, M.L. Flonta, G. Reid., and Obsahuje bibliografii

Language:

English

Rights:

http://creativecommons.org/licenses/by-nc-sa/4.0/
policy:public

Source:

Physiological research | 2001 Volume:50 | Number:6

Harvested from:

CDK

Metadata only:

false