General Physiology and Biophysics Vol.33, No.3, p.321–334, 2014
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Title: A chloride conductance exhibiting bicarbonate conductivity in renal inner medullary collecting duct cells |
Author: Juan J. Bolívar, César O. Lara-Figueroa, Ramón H. Martínez-Mayorquin, Florencio Monroy-Romero, Gabina Arenas |
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Abstract: The anion conductance in primary cultures of rat inner medullary collecting duct cells was studied using perforated-patch whole-cell clamp technique. Depolarizations above 0 mV induced an outward anionic current with a time-dependent activation (Iovt) exhibiting a similar conductivity to Cl– and HCO3–. Iovt showed half-maximal activation around 32 mV with a slope factor of 23 mV, and showed a voltage-dependent activation time course that was well fitted by a sum of two exponential functions. Iovt was potentiated when external pH values or external Ca2+ concentration was increased and was blocked by external DIDS, DPC and furosemide. These characteristics of Iovt resemble that of the ClC-K1 channels-mediated currents; however, anion substitution studies showed that Iovt exhibits a Br– > Cl– > I– > NO3– conductivity sequence, different from that observed in the ClC-K1 channels-mediated conductance. We suggest that, in inner medullary collecting duct cells, ClC-K channels of an unidentified type give rise to this Cl– and HCO3– conductance. This is the first study of a channel-mediated HCO3– current in kidney tubular cells.
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Keywords: Kidney — Anion channel — Bicarbonate transport — Cl– current — IMCD |
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Year: 2014, Volume: 33, Issue: 3 |
Page From: 321, Page To: 334 |
doi:10.4149/gpb_2014006
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