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Potassium secretion by nonsensory region of gerbil utricle in vitro.
Am J Physiol. 1987 Oct; 253(4 Pt 2):F613-21.AJ

Abstract

The isolated nonsensory region of the gerbil utricle in vitro produced a lumen-positive transepithelial electrical potential difference (VT) of +5.7 mV and a luminal fluid containing 106 mM K when bathed in mammalian Ringer solution (5 mM K and 150 mM Na). The lumen of this region was perfused in vitro with K-free solution and the luminal [K], VT, and transepithelial resistance (RT) were measured before and following perfusion under control conditions and after addition of bumetanide (0.1 mM) or ouabain (1 mM) to the bath. The perfusate contained a reduced [Ca], since the average value of utricular endolymph in vivo (0.28 +/- 0.03 mM) measured with Ca-selective microelectrodes was 38% of that in perilymph. Under control conditions, the luminal [K] initially increased at a rate of 2.13 mumol X cm-2 X h-1 after perfusion; net secretion continued until the luminal [K] returned to its preperfusion level. This flux rate corresponds to 57 microA/cm2. The "equivalent short-circuit current" (Equiv. Isc; VT/RT) was found to average 61 microA/cm2. Both K secretion and VT were fully inhibited by bumetanide and by ouabain. Luminal application of Ba (5 mM) in K-free solution had no effect on the initial rate of K secretion, but did prevent full recovery of luminal [K] to the control level. These results are the first estimates of K secretion by the nonsensory cells of the utricle and are the first to directly demonstrate inhibition of K secretion in the inner ear by bumetanide and in the nonsensory tissue of the utricle by ouabain.

Authors+Show Affiliations

Department of Otolaryngology, Washington University, St. Louis, Missouri 63110.No affiliation info available

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

3661715

Citation

Marcus, N Y., and D C. Marcus. "Potassium Secretion By Nonsensory Region of Gerbil Utricle in Vitro." The American Journal of Physiology, vol. 253, no. 4 Pt 2, 1987, pp. F613-21.
Marcus NY, Marcus DC. Potassium secretion by nonsensory region of gerbil utricle in vitro. Am J Physiol. 1987;253(4 Pt 2):F613-21.
Marcus, N. Y., & Marcus, D. C. (1987). Potassium secretion by nonsensory region of gerbil utricle in vitro. The American Journal of Physiology, 253(4 Pt 2), F613-21.
Marcus NY, Marcus DC. Potassium Secretion By Nonsensory Region of Gerbil Utricle in Vitro. Am J Physiol. 1987;253(4 Pt 2):F613-21. PubMed PMID: 3661715.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Potassium secretion by nonsensory region of gerbil utricle in vitro. AU - Marcus,N Y, AU - Marcus,D C, PY - 1987/10/1/pubmed PY - 1987/10/1/medline PY - 1987/10/1/entrez SP - F613 EP - 21 JF - The American journal of physiology JO - Am. J. Physiol. VL - 253 IS - 4 Pt 2 N2 - The isolated nonsensory region of the gerbil utricle in vitro produced a lumen-positive transepithelial electrical potential difference (VT) of +5.7 mV and a luminal fluid containing 106 mM K when bathed in mammalian Ringer solution (5 mM K and 150 mM Na). The lumen of this region was perfused in vitro with K-free solution and the luminal [K], VT, and transepithelial resistance (RT) were measured before and following perfusion under control conditions and after addition of bumetanide (0.1 mM) or ouabain (1 mM) to the bath. The perfusate contained a reduced [Ca], since the average value of utricular endolymph in vivo (0.28 +/- 0.03 mM) measured with Ca-selective microelectrodes was 38% of that in perilymph. Under control conditions, the luminal [K] initially increased at a rate of 2.13 mumol X cm-2 X h-1 after perfusion; net secretion continued until the luminal [K] returned to its preperfusion level. This flux rate corresponds to 57 microA/cm2. The "equivalent short-circuit current" (Equiv. Isc; VT/RT) was found to average 61 microA/cm2. Both K secretion and VT were fully inhibited by bumetanide and by ouabain. Luminal application of Ba (5 mM) in K-free solution had no effect on the initial rate of K secretion, but did prevent full recovery of luminal [K] to the control level. These results are the first estimates of K secretion by the nonsensory cells of the utricle and are the first to directly demonstrate inhibition of K secretion in the inner ear by bumetanide and in the nonsensory tissue of the utricle by ouabain. SN - 0002-9513 UR - https://www.unboundmedicine.com/medline/citation/3661715/Potassium_secretion_by_nonsensory_region_of_gerbil_utricle_in_vitro_ L2 - http://journals.physiology.org/doi/full/10.1152/ajprenal.1987.253.4.F613?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -