Abstract
Isolated guinea pig type I vestibular hair cells were voltage clamped at HP-110 mV in whole cell clamp configuration and depolarized up to +20 mV. Increasing depolarizations elicited large outward currents. These currents were replaced, in cesium-loaded cells, by inward/outward currents that reversed at membrane potentials between −55 and −30 mV. The reversal potential varied from cell to cell, and appeared to depend on the intracellular potassium cesium ratio. The current remaining in the presence of intracellular cesium was essentially due to a non-typical potassium conductance, which decreased in the presence of 4-AP and was blocked by 4-AP plus TEA. This current appeared as soon as the membrane was depolarized, showing the high potassium permeability of type I vestibular hair cells. A small part of this current was a strictly calcium inward current, sensitive to flunarizine, with a leakage component in the hyperpolarized state and a voltage component when the cell was depolarized.
References
Assad JA, Hacohen N, Corey DP (1989) Voltage dependence of adaptation and active bundle movement in bullfrog saccular hair cells. Proc Natl Acad Sci USA 86: 2918–2922
Benham CD, Tsien W (1987) Calcium permeable channels in vascular smooth muscle: voltage activated, receptor operator and leak channels. In: Mandel LJ and Eaton DC (ed) “Cell calcium and the control of membrane transport”, Soc Gen Phys 40th Ann Symp, Rockteller University Press NY, pp 45–64
Griguer C, Lehouelleur J, Valat J, Sahuquet A, Sans A (1992) Voltage dependent reversible movements of the apex in isolated guinea pig vestibular hair cells. Hear Res. (in press)
Howard J, Hudspeth AJ (1988) Compliance of the hair bundle associated with gating of mechanoelectrical transduction channels in the bullfrog's saccular hair cell. Neuron 1: 189–199
Kros CJ, Crawford AC (1990) Potassium currents in inner hair cells isolated from the guinea pig cochlea. J Physiol 421: 263–291
Rennie KJ, Asmore JF (1991) Ionic currents in isolated vestibular hair cells from the guinea pig crista ampullaris. Hear Res 51: 279–292
Santos-Sacchi J (1991) Reversible inhibition of voltage-dependent outer hair cell motility and capacitance. J Neurosci 11: 3096–3110
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Griguer, C., Sans, A. & Lehouelleur, J. Non-typical K+-current in cesium-loaded guinea pig type I vestibular hair cell. Pflügers Arch. 422, 407–409 (1993). https://doi.org/10.1007/BF00374300
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DOI: https://doi.org/10.1007/BF00374300