Hyperpolarization-activated Na(+)-K+ current (Ih) in neocortical neurons is blocked by external proteolysis and internal TEA

T Budde; John A White; A R Kay

doi:10.1152/jn.1994.72.6.2737

Back

Hyperpolarization-activated Na(+)-K+ current (Ih) in neocortical neurons is blocked by external proteolysis and internal TEA

Journal article

Peer reviewed

Hyperpolarization-activated Na(+)-K+ current (Ih) in neocortical neurons is blocked by external proteolysis and internal TEA

T Budde, John A White and A R Kay

Journal of neurophysiology, Vol.72(6), pp.2737-2742

12/1994

DOI: 10.1152/jn.1994.72.6.2737

PMID: 7534826

View Online

Abstract

1. After 1 day in culture, neurons derived from the neonatal cerebral cortex of the rat exhibited a slowly activating current gated by hyperpolarizing voltage clamp pulses. The current was blocked by extracellular Cs+ and unaffected by extracellular Ba2+, and was permeable to both Na+ and K+ (PNa/PK = 0.29). Its form and pharmacology are consistent with a current termed Ih in other preparations. 2. Ih was absent from cells acutely dissociated from both the neonatal and mature cerebral cortex, despite the use of low enzyme concentrations. The sensitivity of Ih to extracellular proteolysis was demonstrated by superfusing the cells with trypsin (1 mg/ml) while monitoring the presence of Ih in the whole cell mode of recording. Ih was rapidly abolished (t1/2 approximately 5 min at 22 degrees C) by proteolysis and exhibited no shifts in its range of activation or changes in its activation kinetics during the course of the digestion. 3. Intracellular tetraethylammonium (TEA), at a concentration of < 15 mM was shown to block Ih completely, while extracellular TEA had no effect on the current. This suggests that the inner vestibule of Ih may be structurally related to that of potassium channels.

Electrophysiology

Cells, Cultured

Rats

Ion Channels - drug effects

Sodium Channels - drug effects

Potassium Channels - drug effects

Cerebral Cortex - cytology

Cerebral Cortex - metabolism

Tetraethylammonium Compounds - pharmacology

Potassium Channels - metabolism

Patch-Clamp Techniques

Animals

Trypsin - pharmacology

Ion Channels - metabolism

Sodium Channels - metabolism

Neurons - metabolism

Ion Channel Gating - drug effects

Details

Title: Subtitle: Hyperpolarization-activated Na(+)-K+ current (Ih) in neocortical neurons is blocked by external proteolysis and internal TEA
Creators: T Budde - Department of Biological Sciences, University of Iowa, Iowa City 52242
John A White - University of Iowa
A R Kay
Resource Type: Journal article
Publication Details: Journal of neurophysiology, Vol.72(6), pp.2737-2742
DOI: 10.1152/jn.1994.72.6.2737
PMID: 7534826
NLM abbreviation: J Neurophysiol
ISSN: 0022-3077
eISSN: 1522-1598
Publisher: United States
Language: English
Date published: 12/1994
Academic Unit: Iowa Neuroscience Institute; Biology
Record Identifier: 9983992079102771

Metrics

29 Record Views

36 Times Cited - Web of Science