Korean J Otolaryngol-Head Neck Surg.  2002 Jun;45(6):550-556.

Outward Rectifying Current in Isolated Deiters' Cells from Guinea Pig Cochlea

• Kim HJ
• Ahn JH
• Kim WT
• Leem CH
• Chung JW
• Lee KS

Abstract

BACKGROUND AND OBJECTIVES: The Deiters' cell is one of the supporting cells in the organ of Corti and is known to possibly regulate the signal transduction pathway in the organ of Corti. The signal transduction process can be modulated by ATP and acetylcholine, the so-called neurotransmitters, in Deiters' cells. Intracellular Ca2+ concentration can be also increased by these neurotransmitters and the control mechanism on the organ of Corti is highly suggested in Deiters' cells. Potassium ion (K+) is known to be important both in hair cells and supporting cells. Through K+ channel, the membrane potential may be controlled and the signal transduction pathway can be regulated. Furthermore, the motility of outer hair cell and the signal transduction from the apical stereocilia are considered to be regulated by this channel. The aim of this study is to record the K+ current in the isolated Deiters' cells from guinea pig cochlea.
MATERIALS AND METHODS
Deiters' cells were isolated from the organ of Corti of guinea pig by using collagenase and a pipet. A whole cell patch clamp was performed under the inverted microscope and the current was measured with List-7 amplifier and pClamp 8.0.2 software.
RESULTS
The resting membrane potential was -15.02+/-2.66 mV (n=6). When the cell membrane was hyperpolarized into -110 mV from the -40 mV holding potential, the peak current was -227+/-39.9 pA (n=15). After having depolarized to the maximum, (50 mV), the peak current was 7123+/-737 pA, and the reversal potentials of different external K+ concentration changed in the K+-dependent manner. About 80% of this current was inhibited by TEA. When K+ was substituted by Cs+, the peak current was 1788+/-231 pA at 50 mV step pulse. Activation curve of this outward current showed two different Vh (half activation voltage) and K (slope factor).
CONCLUSION
Outward rectifying K+ channels exist in Deiters' cells and they can be inhibited by TEA and permeable to Cs+. More than two types of K+ current can exist and they may play a role in the recovery of membrane potential after depolarization,

Keyword

Potassium channels; Organ of corti; Labyrinth supporting cells; Patch-Clamp techniques; Signal transduction

MeSH Terms

Acetylcholine
Adenosine Triphosphate
Animals
Cell Membrane
Cochlea*
Collagenases
Guinea Pigs*
Guinea*
Hair
Labyrinth Supporting Cells
Membrane Potentials
Neurotransmitter Agents
Organ of Corti
Patch-Clamp Techniques
Potassium
Potassium Channels
Signal Transduction
Stereocilia
Tea
Acetylcholine
Adenosine Triphosphate
Collagenases
Neurotransmitter Agents
Potassium
Potassium Channels
Tea