K+ current distribution in rat sub-epicardial ventricular myocytes

Kimiaki Komukai; Fabien Brette; Tomoko T. Yamanushi; Clive H. Orchard

doi:10.1007/s00424-002-0851-8

K+ current distribution in rat sub-epicardial ventricular myocytes

Kimiaki Komukai, Fabien Brette, Tomoko T. Yamanushi, Clive H. Orchard

Research output: Contribution to journal › Article › peer-review

Abstract

In the rat ventricle, the transient outward K+ current (ITO) is carried by heteromeric channels composed of Kv4.2 and Kv4.3. However its distribution in the cell membrane is unclear: immunohistochemical studies of Kv4.2 distribution in the cardiac ventricular cell membrane have given equivocal results, and there are no corresponding studies of Kv4.3. We therefore used detubulated cardiac cells to investigate the functional distribution of ITO between the t-tubules and surface membrane. ITO, the delayed rectifier (IK), the inward rectifier (IK1) and steady-state (ISS) K+ currents were monitored using the patch-clamp technique in control and formamide-treated (detubulated) cells from rat left ventricular sub-epicardium. Formamide treatment decreased cell capacitance by 20%, did not significantly change the density of ITO, IK or IK1 but decreased the density of ISS and L-type Ca current (ICa). These data suggest that ITO, IK, and IK1 are uniformly distributed between the surface and t-tubule membranes, but that ISS and ICa are concentrated in the t-tubules.

Original language	English
Pages (from-to)	532-538
Number of pages	6
Journal	Pflügers Archiv European Journal of Physiology
Volume	444
Issue number	4
DOIs	https://doi.org/10.1007/s00424-002-0851-8
Publication status	Published - 2002

Keywords

Ca current
Formamide
K current
Transverse tubule
Whole cell

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10.1007/s00424-002-0851-8

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title = "K+ current distribution in rat sub-epicardial ventricular myocytes",

abstract = "In the rat ventricle, the transient outward K+ current (ITO) is carried by heteromeric channels composed of Kv4.2 and Kv4.3. However its distribution in the cell membrane is unclear: immunohistochemical studies of Kv4.2 distribution in the cardiac ventricular cell membrane have given equivocal results, and there are no corresponding studies of Kv4.3. We therefore used detubulated cardiac cells to investigate the functional distribution of ITO between the t-tubules and surface membrane. ITO, the delayed rectifier (IK), the inward rectifier (IK1) and steady-state (ISS) K+ currents were monitored using the patch-clamp technique in control and formamide-treated (detubulated) cells from rat left ventricular sub-epicardium. Formamide treatment decreased cell capacitance by 20%, did not significantly change the density of ITO, IK or IK1 but decreased the density of ISS and L-type Ca current (ICa). These data suggest that ITO, IK, and IK1 are uniformly distributed between the surface and t-tubule membranes, but that ISS and ICa are concentrated in the t-tubules.",

keywords = "Ca current, Formamide, K current, Transverse tubule, Whole cell",

author = "Kimiaki Komukai and Fabien Brette and Yamanushi, {Tomoko T.} and Orchard, {Clive H.}",

year = "2002",

doi = "10.1007/s00424-002-0851-8",

language = "English",

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journal = "Pfl{\"u}gers Archiv European Journal of Physiology",

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TY - JOUR

T1 - K+ current distribution in rat sub-epicardial ventricular myocytes

AU - Komukai, Kimiaki

AU - Brette, Fabien

AU - Yamanushi, Tomoko T.

AU - Orchard, Clive H.

PY - 2002

Y1 - 2002

N2 - In the rat ventricle, the transient outward K+ current (ITO) is carried by heteromeric channels composed of Kv4.2 and Kv4.3. However its distribution in the cell membrane is unclear: immunohistochemical studies of Kv4.2 distribution in the cardiac ventricular cell membrane have given equivocal results, and there are no corresponding studies of Kv4.3. We therefore used detubulated cardiac cells to investigate the functional distribution of ITO between the t-tubules and surface membrane. ITO, the delayed rectifier (IK), the inward rectifier (IK1) and steady-state (ISS) K+ currents were monitored using the patch-clamp technique in control and formamide-treated (detubulated) cells from rat left ventricular sub-epicardium. Formamide treatment decreased cell capacitance by 20%, did not significantly change the density of ITO, IK or IK1 but decreased the density of ISS and L-type Ca current (ICa). These data suggest that ITO, IK, and IK1 are uniformly distributed between the surface and t-tubule membranes, but that ISS and ICa are concentrated in the t-tubules.

AB - In the rat ventricle, the transient outward K+ current (ITO) is carried by heteromeric channels composed of Kv4.2 and Kv4.3. However its distribution in the cell membrane is unclear: immunohistochemical studies of Kv4.2 distribution in the cardiac ventricular cell membrane have given equivocal results, and there are no corresponding studies of Kv4.3. We therefore used detubulated cardiac cells to investigate the functional distribution of ITO between the t-tubules and surface membrane. ITO, the delayed rectifier (IK), the inward rectifier (IK1) and steady-state (ISS) K+ currents were monitored using the patch-clamp technique in control and formamide-treated (detubulated) cells from rat left ventricular sub-epicardium. Formamide treatment decreased cell capacitance by 20%, did not significantly change the density of ITO, IK or IK1 but decreased the density of ISS and L-type Ca current (ICa). These data suggest that ITO, IK, and IK1 are uniformly distributed between the surface and t-tubule membranes, but that ISS and ICa are concentrated in the t-tubules.

KW - Ca current

KW - Formamide

KW - K current

KW - Transverse tubule

KW - Whole cell

U2 - 10.1007/s00424-002-0851-8

DO - 10.1007/s00424-002-0851-8

M3 - Article

SN - 0031-6768

VL - 444

SP - 532

EP - 538

JO - Pflügers Archiv European Journal of Physiology

JF - Pflügers Archiv European Journal of Physiology

IS - 4

ER -

K+ current distribution in rat sub-epicardial ventricular myocytes

Abstract

Keywords

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