QX-314 restores gating charge immobilization abolished by chloramine-T treatment in squid giant axons

J. Tanguy*, J. Yeh

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

The gating status of the QX-314 bound Na channels before and after suppressing the fast inactivation by chloramine-T (CT) was investigated by studying the gating charge immobilization using the OFF gating current (Ig,OFF). CT treatment, which abolishes the charge immobilization induced by a prolonged depolarization, altered the kinetics of Ig,OFF: the fast phase became insensitive to the pulse duration and the slow phase became three times faster than the control one. However, internally applied QX-314 (in the presence of external TTX) caused an immediate charge immobilization similar to that observed in the absence of CT treatment. The Ig,OFF exhibited kinetics similar to the inactivated channels, decaying with a very fast time course. We conclude that the charge immobilization is restored by QX-314 in the chloramine-T-treated axon and that the gating state of the QX-314-bound channel is similar to the inactivated one. The role of the gating charge immobilization in the use-dependent block mechanism is discussed.

Original languageEnglish (US)
Pages (from-to)421-427
Number of pages7
JournalBiophysical Journal
Volume56
Issue number2
DOIs
StatePublished - 1989

ASJC Scopus subject areas

  • Biophysics

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