Inwardly rectifying K+ currents in intermediate cells in the cochlea of gerbils: a possible contribution to the endocochlear potential.
The stria vascularis in the cochlea generates the endocochlear potential (EP) and secretes K+-rich endolymph; both are indispensable for normal sound transduction by hair cells. K+ conductance in the intermediate cell, one of the several types of cells constituting the stria vascularis, was investigated by the whole-cell patch-clamp technique. Inwardly-rectifying K+ (Kir) currents were the major currents observed. The currents were inhibited dose-dependently by Ba2+, quinine, verapamil and Cs+, but not by tetraethylammonium (20 mM), 4-aminopyridine (5 mM) or Cd2+ (1 mM). The similarity between the effect of inhibitors on Kir currents and on the EP (Takeuchi et al., Hearing Res., 101 (1996) 181-185) suggests a direct contribution of the Kir conductance to the generation of the EP.
Takeuchi
S
S
Department of Physiology, Kochi Medical School, Nankoku, Japan. takeuchi@kochi-ms.ac.jp
Ando
M
M
D015761:4-Aminopyridine / Q000494:pharmacology; D000818:Animals; D001464:Barium / Q000494:pharmacology; D002104:Cadmium / Q000494:pharmacology; D002586:Cesium / Q000494:pharmacology; D003055:Cochlear Microphonic Potentials / Q000187:drug effects / Q000502:physiology*; D004710:Endolymph / Q000378:metabolism; D005849:Gerbillinae; D017136:Ion Transport / Q000187:drug effects; D008959:Models, Neurological; D009419:Nerve Tissue Proteins / Q000187:drug effects / Q000502:physiology*; D018408:Patch-Clamp Techniques; D011188:Potassium / Q000502:physiology*; D015221:Potassium Channels / Q000187:drug effects / Q000502:physiology*; D024661:Potassium Channels, Inwardly Rectifying; D011803:Quinine / Q000494:pharmacology; D013316:Stria Vascularis / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D019789:Tetraethylammonium / Q000494:pharmacology; D014700:Verapamil / Q000494:pharmacology
D009419:Nerve Tissue Proteins; D015221:Potassium Channels; D024661:Potassium Channels, Inwardly Rectifying; D002104:Cadmium; D002586:Cesium; D001464:Barium; D019789:Tetraethylammonium; D011803:Quinine; D015761:4-Aminopyridine; D014700:Verapamil; D011188:Potassium