Tags

Type your tag names separated by a space and hit enter

Sodium transfer from endolymph through a luminal amiloride-sensitive channel.
Am J Physiol. 1989 Aug; 257(2 Pt 2):F182-9.AJ

Abstract

An in vitro preparation of frog semicircular canal was devised to study the mechanisms of Na transport across the labyrinthine epithelium. When the lumen of the semicircular canal was filled with perilymph-like solution, the structure was able to secrete K into and to absorb Na from the lumen and to generate a lumen-positive transepithelial potential. When the lumen of the semicircular canal was filled with endolymph-like solution, the electrochemical composition of the luminal fluid was partly maintained up to 2 h. In this last experimental condition net and unidirectional fluxes were calculated in absence or presence of transport inhibitors, separately for the ampulla and for the nonampullar part of the canal. Amiloride (10(-5) M) but not dimethyl amiloride (10(-5) M) inhibited 60% of the unidirectional Na efflux out of endolymph; this Na efflux decrease resulted in an increase of the inward net Na flux. The net Na flux was also increased after abluminal application of ouabain (10(-3) M), furosemide (10(-4) M), and bumetanide (10(-6) M). This study validates this isolated preparation as a suitable tool for the study of endolymph secretion, confirms that the secretion of endolymph is achieved in the ampulla, and provides evidence for an apical amiloride-sensitive Na channel through which Na is transferred out of endolymph along an electrochemical gradient provided by the activity of the abluminal Na+-K+-ATPase.

Authors+Show Affiliations

Department of Physiology, Faculté Xavier Bichat, Université Paris, Institut National de la Santé et de la Recherche Médicale U.251, France.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

2548398

Citation

Ferrary, E, et al. "Sodium Transfer From Endolymph Through a Luminal Amiloride-sensitive Channel." The American Journal of Physiology, vol. 257, no. 2 Pt 2, 1989, pp. F182-9.
Ferrary E, Bernard C, Oudar O, et al. Sodium transfer from endolymph through a luminal amiloride-sensitive channel. Am J Physiol. 1989;257(2 Pt 2):F182-9.
Ferrary, E., Bernard, C., Oudar, O., Sterkers, O., & Amiel, C. (1989). Sodium transfer from endolymph through a luminal amiloride-sensitive channel. The American Journal of Physiology, 257(2 Pt 2), F182-9.
Ferrary E, et al. Sodium Transfer From Endolymph Through a Luminal Amiloride-sensitive Channel. Am J Physiol. 1989;257(2 Pt 2):F182-9. PubMed PMID: 2548398.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Sodium transfer from endolymph through a luminal amiloride-sensitive channel. AU - Ferrary,E, AU - Bernard,C, AU - Oudar,O, AU - Sterkers,O, AU - Amiel,C, PY - 1989/8/1/pubmed PY - 1989/8/1/medline PY - 1989/8/1/entrez SP - F182 EP - 9 JF - The American journal of physiology JO - Am. J. Physiol. VL - 257 IS - 2 Pt 2 N2 - An in vitro preparation of frog semicircular canal was devised to study the mechanisms of Na transport across the labyrinthine epithelium. When the lumen of the semicircular canal was filled with perilymph-like solution, the structure was able to secrete K into and to absorb Na from the lumen and to generate a lumen-positive transepithelial potential. When the lumen of the semicircular canal was filled with endolymph-like solution, the electrochemical composition of the luminal fluid was partly maintained up to 2 h. In this last experimental condition net and unidirectional fluxes were calculated in absence or presence of transport inhibitors, separately for the ampulla and for the nonampullar part of the canal. Amiloride (10(-5) M) but not dimethyl amiloride (10(-5) M) inhibited 60% of the unidirectional Na efflux out of endolymph; this Na efflux decrease resulted in an increase of the inward net Na flux. The net Na flux was also increased after abluminal application of ouabain (10(-3) M), furosemide (10(-4) M), and bumetanide (10(-6) M). This study validates this isolated preparation as a suitable tool for the study of endolymph secretion, confirms that the secretion of endolymph is achieved in the ampulla, and provides evidence for an apical amiloride-sensitive Na channel through which Na is transferred out of endolymph along an electrochemical gradient provided by the activity of the abluminal Na+-K+-ATPase. SN - 0002-9513 UR - https://www.unboundmedicine.com/medline/citation/2548398/Sodium_transfer_from_endolymph_through_a_luminal_amiloride_sensitive_channel_ L2 - http://www.physiology.org/doi/full/10.1152/ajprenal.1989.257.2.F182?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -