Voltage-dependent outward K+ current in intermediate cell of stria vascularis of gerbil cochlea

Shunji Takeuchi, Motonori Ando

Research output: Contribution to journalArticle

21 Citations (Scopus)

Abstract

A voltage-dependent outward K+ (K(v)) current in the intermediate cell (melanocyte) of the cochlear stria vascularis was studied using the whole cell patch-clamp technique. The K(v) current had an activation threshold voltage of approximately -80 mV, and 50% activation was observed at -42.6 mV. The time courses of activation and inactivation were well fitted by two exponential functions: the time constants at 0 mV were 7.9 and 58.8 ms for activation and 0.6 and 4.3 s for inactivation. The half-maximal activation time was 13.8 ms at 0 mV. Inactivation of the current was incomplete even after a prolonged depolarization of 10 s. This current was independent of intracellular Ca2+. Quinine, verapamil, Ba2+, and tetraethylammonium inhibited the current in a dose-dependent manner, but 4-aminopyridine was ineffective at 50 mM. We conclude that the K(v) conductance in the intermediate cell may stabilize the membrane potential, which is thought to be closely related to the endocochlear potential, and may provide an additional route for K+ secretion into the intercellular space.

Original languageEnglish
JournalAmerican Journal of Physiology - Cell Physiology
Volume277
Issue number1 46-1
Publication statusPublished - 1999
Externally publishedYes

Fingerprint

Stria Vascularis
Gerbillinae
Cochlea
Chemical activation
Electric potential
4-Aminopyridine
Tetraethylammonium
Quinine
Melanocytes
Extracellular Space
Patch-Clamp Techniques
Verapamil
Membrane Potentials
Exponential functions
Depolarization
Clamping devices
Threshold voltage
Membranes

Keywords

  • Endocochlear potential
  • Melanocyte
  • Patch clamp

ASJC Scopus subject areas

  • Clinical Biochemistry
  • Cell Biology
  • Physiology
  • Physiology (medical)

Cite this

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title = "Voltage-dependent outward K+ current in intermediate cell of stria vascularis of gerbil cochlea",
abstract = "A voltage-dependent outward K+ (K(v)) current in the intermediate cell (melanocyte) of the cochlear stria vascularis was studied using the whole cell patch-clamp technique. The K(v) current had an activation threshold voltage of approximately -80 mV, and 50{\%} activation was observed at -42.6 mV. The time courses of activation and inactivation were well fitted by two exponential functions: the time constants at 0 mV were 7.9 and 58.8 ms for activation and 0.6 and 4.3 s for inactivation. The half-maximal activation time was 13.8 ms at 0 mV. Inactivation of the current was incomplete even after a prolonged depolarization of 10 s. This current was independent of intracellular Ca2+. Quinine, verapamil, Ba2+, and tetraethylammonium inhibited the current in a dose-dependent manner, but 4-aminopyridine was ineffective at 50 mM. We conclude that the K(v) conductance in the intermediate cell may stabilize the membrane potential, which is thought to be closely related to the endocochlear potential, and may provide an additional route for K+ secretion into the intercellular space.",
keywords = "Endocochlear potential, Melanocyte, Patch clamp",
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T1 - Voltage-dependent outward K+ current in intermediate cell of stria vascularis of gerbil cochlea

AU - Takeuchi, Shunji

AU - Ando, Motonori

PY - 1999

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N2 - A voltage-dependent outward K+ (K(v)) current in the intermediate cell (melanocyte) of the cochlear stria vascularis was studied using the whole cell patch-clamp technique. The K(v) current had an activation threshold voltage of approximately -80 mV, and 50% activation was observed at -42.6 mV. The time courses of activation and inactivation were well fitted by two exponential functions: the time constants at 0 mV were 7.9 and 58.8 ms for activation and 0.6 and 4.3 s for inactivation. The half-maximal activation time was 13.8 ms at 0 mV. Inactivation of the current was incomplete even after a prolonged depolarization of 10 s. This current was independent of intracellular Ca2+. Quinine, verapamil, Ba2+, and tetraethylammonium inhibited the current in a dose-dependent manner, but 4-aminopyridine was ineffective at 50 mM. We conclude that the K(v) conductance in the intermediate cell may stabilize the membrane potential, which is thought to be closely related to the endocochlear potential, and may provide an additional route for K+ secretion into the intercellular space.

AB - A voltage-dependent outward K+ (K(v)) current in the intermediate cell (melanocyte) of the cochlear stria vascularis was studied using the whole cell patch-clamp technique. The K(v) current had an activation threshold voltage of approximately -80 mV, and 50% activation was observed at -42.6 mV. The time courses of activation and inactivation were well fitted by two exponential functions: the time constants at 0 mV were 7.9 and 58.8 ms for activation and 0.6 and 4.3 s for inactivation. The half-maximal activation time was 13.8 ms at 0 mV. Inactivation of the current was incomplete even after a prolonged depolarization of 10 s. This current was independent of intracellular Ca2+. Quinine, verapamil, Ba2+, and tetraethylammonium inhibited the current in a dose-dependent manner, but 4-aminopyridine was ineffective at 50 mM. We conclude that the K(v) conductance in the intermediate cell may stabilize the membrane potential, which is thought to be closely related to the endocochlear potential, and may provide an additional route for K+ secretion into the intercellular space.

KW - Endocochlear potential

KW - Melanocyte

KW - Patch clamp

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