Non-stationary fluctuation analysis of the Na current in myelinated nerve fibers of Xenopus laevis: experiments and stochastic simulations.
Biosystems
; 62(1-3): 13-28, 2001.
Article
en En
| MEDLINE
| ID: mdl-11595316
Na current fluctuations under voltage-clamp conditions during pulse steps in the potential range from -65 to -30 mV were measured in myelinated nerve fibers of Xenopus laevis. The covariance functions for four consecutive 1 ms intervals were calculated. The time courses of the covariance functions were well fitted with monoexponential functions with time constants between 0.5 and 3 ms, larger at the end of the pulse and larger at more positive potentials. To analyze the underlying channel kinetics we simulated current fluctuations at a step to -35 mV of eight published Na channel models and calculated corresponding covariance functions. None of the models did explain the experimental fluctuation results. We therefore developed a new Na channel model that satisfactorily described the results. Features that distinguished this model from the other tested ones were a slower deactivation rate, and an inactivation transition directly from a closed state.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Sodio
/
Canales de Sodio
/
Modelos Biológicos
/
Fibras Nerviosas
Límite:
Animals
Idioma:
En
Revista:
Biosystems
Año:
2001
Tipo del documento:
Article
País de afiliación:
Suecia
Pais de publicación:
Irlanda