Defining the conductance of the closed state in a voltage-gated K+ channel.
Neuron
; 38(1): 61-7, 2003 Apr 10.
Article
en En
| MEDLINE
| ID: mdl-12691664
ABSTRACT
The opening and closing of the ion conduction pathway in ion channels underlies the generation and propagation of electrical signals in biological systems. Although electrophysiological approaches to measuring the flow of ions in the open state have contributed profoundly to our understanding of ion permeation and gating, it remains unclear how much the ion-throughput rate decreases upon closure of the ion conduction pore. To address this fundamental question, we expressed the Shaker Kv channel at high levels and then measured macroscopic K+ currents at negative membrane voltages and counted the number of channels by quantifying the translocation of gating charge. Our results show that the conductance of the closed state is between 0 and 0.16 fS, or at least 100,000 times lower than for the open state of the channel, indicating that the flow of ions is very tightly regulated in this class of K+ channels.
Buscar en Google
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Canales de Potasio
/
Activación del Canal Iónico
Límite:
Animals
Idioma:
En
Revista:
Neuron
Asunto de la revista:
NEUROLOGIA
Año:
2003
Tipo del documento:
Article
País de afiliación:
Estados Unidos