Slow inactivation of sodium currents in the rat nodose neurons.
Auton Neurosci
; 87(2-3): 209-16, 2001 Mar 23.
Article
em En
| MEDLINE
| ID: mdl-11476281
ABSTRACT
Nodose neurons express sodium currents that can be differentiated based on their sensitivity to tetrodotoxin. Several studies have demonstrated significant differences in voltage-dependence and kinetics of activation and inactivation between tetrodotoxin-sensitive and tetrodotoxin-resistant currents. However, little is known about the slow inactivation. Using whole cell patch-clamp technique fast and slow inactivation of sodium currents were studied in cultured rat nodose neurons. Tetrodotoxin-resistant currents recovered much more rapidly after a 15-ms depolarization than tetrodotoxin-sensitive currents. However, repeated 5-ms depolarizations at 10 Hz induced a cumulative inhibition that was more prolonged in tetrodotoxin-resistant compared to tetrodotoxin-sensitive currents. Consistent with these findings, slow inactivation proceeded more rapidly and was more complete for the tetrodotoxin-resistant than for tetrodotoxin-sensitive currents. While the voltage-dependence of fast inactivation differed significantly between the pharmacologically distinct currents, the voltage-dependence of slow inactivation was similar for both sodium currents. We conclude that slow inactivation of sodium currents can be triggered by trains of brief depolarizations. The resulting prolonged decrease in membrane excitability may contribute to the different patterns of action potential generation observed in primary afferent neurons.
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Bases de dados:
MEDLINE
Assunto principal:
Sódio
/
Canais de Sódio
/
Ativação do Canal Iônico
/
Neurônios Aferentes
/
Gânglio Nodoso
Limite:
Animals
Idioma:
En
Revista:
Auton Neurosci
Assunto da revista:
NEUROLOGIA
Ano de publicação:
2001
Tipo de documento:
Article
País de afiliação:
Brasil