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Mechanism generating endocochlear potential: role played by intermediate cells in stria vascularis.
Biophys J. 2000 Nov; 79(5):2572-82.BJ

Abstract

The endocochlear DC potential (EP) is generated by the stria vascularis, and essential for the normal function of hair cells. Intermediate cells are melanocytes in the stria vascularis. To examine the contribution of the membrane potential of intermediate cells (E(m)) to the EP, a comparison was made between the effects of K(+) channel blockers on the E(m) and those on the EP. The E(m) of dissociated guinea pig intermediate cells was measured in the zero-current clamp mode of the whole-cell patch clamp configuration. The E(m) changed by 55.1 mV per 10-fold changes in extracellular K(+) concentration. Ba(2+), Cs(+), and quinine depressed the E(m) in a dose-dependent manner, whereas tetraethylammonium at 30 mM and 4-aminopyridine at 10 mM had no effect. The reduction of the E(m) by Ba(2+) and Cs(+) was enhanced by lowering the extracellular K(+) concentration from 3.6 mM to 1.2 mM. To examine the effect of the K(+) channel blockers on the EP, the EP of guinea pigs was maintained by vascular perfusion, and K(+) channel blockers were administered to the artificial blood. Ba(2+), Cs(+) and quinine depressed the EP in a dose-dependent manner, whereas tetraethylammonium at 30 mM and 4-aminopyridine at 10 mM did not change the EP. A 10-fold increase in the K(+) concentration in the artificial blood caused a minor decrease in the EP of only 10.6 mV. The changes in the EP were similar to those seen in the E(m) obtained at the lower extracellular K(+) concentration of 1.2 mM. On the basis of these results, we propose that the EP is critically dependent on the voltage jump across the plasma membrane of intermediate cells, and that K(+) concentration in the intercellular space in the stria vascularis may be actively controlled at a concentration lower than the plasma level.

Authors+Show Affiliations

Department of Physiology, Kochi Medical School, Nankoku 783-8505, Japan. takeuchi@kochi-ms.ac.jpNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article

Language

eng

PubMed ID

11053131

Citation

Takeuchi, S, et al. "Mechanism Generating Endocochlear Potential: Role Played By Intermediate Cells in Stria Vascularis." Biophysical Journal, vol. 79, no. 5, 2000, pp. 2572-82.
Takeuchi S, Ando M, Kakigi A. Mechanism generating endocochlear potential: role played by intermediate cells in stria vascularis. Biophys J. 2000;79(5):2572-82.
Takeuchi, S., Ando, M., & Kakigi, A. (2000). Mechanism generating endocochlear potential: role played by intermediate cells in stria vascularis. Biophysical Journal, 79(5), 2572-82.
Takeuchi S, Ando M, Kakigi A. Mechanism Generating Endocochlear Potential: Role Played By Intermediate Cells in Stria Vascularis. Biophys J. 2000;79(5):2572-82. PubMed PMID: 11053131.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Mechanism generating endocochlear potential: role played by intermediate cells in stria vascularis. AU - Takeuchi,S, AU - Ando,M, AU - Kakigi,A, PY - 2000/10/29/pubmed PY - 2001/2/28/medline PY - 2000/10/29/entrez SP - 2572 EP - 82 JF - Biophysical journal JO - Biophys. J. VL - 79 IS - 5 N2 - The endocochlear DC potential (EP) is generated by the stria vascularis, and essential for the normal function of hair cells. Intermediate cells are melanocytes in the stria vascularis. To examine the contribution of the membrane potential of intermediate cells (E(m)) to the EP, a comparison was made between the effects of K(+) channel blockers on the E(m) and those on the EP. The E(m) of dissociated guinea pig intermediate cells was measured in the zero-current clamp mode of the whole-cell patch clamp configuration. The E(m) changed by 55.1 mV per 10-fold changes in extracellular K(+) concentration. Ba(2+), Cs(+), and quinine depressed the E(m) in a dose-dependent manner, whereas tetraethylammonium at 30 mM and 4-aminopyridine at 10 mM had no effect. The reduction of the E(m) by Ba(2+) and Cs(+) was enhanced by lowering the extracellular K(+) concentration from 3.6 mM to 1.2 mM. To examine the effect of the K(+) channel blockers on the EP, the EP of guinea pigs was maintained by vascular perfusion, and K(+) channel blockers were administered to the artificial blood. Ba(2+), Cs(+) and quinine depressed the EP in a dose-dependent manner, whereas tetraethylammonium at 30 mM and 4-aminopyridine at 10 mM did not change the EP. A 10-fold increase in the K(+) concentration in the artificial blood caused a minor decrease in the EP of only 10.6 mV. The changes in the EP were similar to those seen in the E(m) obtained at the lower extracellular K(+) concentration of 1.2 mM. On the basis of these results, we propose that the EP is critically dependent on the voltage jump across the plasma membrane of intermediate cells, and that K(+) concentration in the intercellular space in the stria vascularis may be actively controlled at a concentration lower than the plasma level. SN - 0006-3495 UR - https://www.unboundmedicine.com/medline/citation/11053131/Mechanism_generating_endocochlear_potential:_role_played_by_intermediate_cells_in_stria_vascularis_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0006-3495(00)76497-6 DB - PRIME DP - Unbound Medicine ER -