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Bumetanide-induced enlargement of the intercellular space in the stria vascularis critically depends on Na+ transport.
Hear Res 2003; 186(1-2):1-9HR

Abstract

The intercellular space in the stria vascularis (intrastrial space) is a closed space and isolated from both the endolymph and the perilymph in normal tissue. Loop diuretics such as bumetanide and furosemide cause an acute enlargement of the intrastrial space in association with a decline in the endocochlear potential. It is known that bumetanide inhibits the Na+-K+-2Cl- cotransporter, which is expressed abundantly in the basolateral membrane of marginal cells. We studied ionic mechanisms underlying the bumetanide-induced enlargement of the intrastrial space using perilymphatic perfusion in guinea pigs. Perilymphatic perfusion with artificial perilymph containing 100 microM bumetanide caused marked enlargement of the intrastrial space, as reported previously. Removal of K+ from the perilymph did not affect the bumetanide-induced enlargement, whereas removal of Na+ from the perilymph inhibited it almost completely. Perilymph containing 1 mM amiloride also inhibited the enlargement of the intrastrial space almost completely. These results indicate that perilymphatic Na+, but not K+, and amiloride-sensitive pathways are essential to the bumetanide-induced enlargement of the intrastrial space. Two possible pathways could yield these results. Na+ in the perilymph could enter the endolymph via Reissner's membrane or the basilar membrane; Na+ in the endolymph would then be taken up by marginal cells via the apical membrane and secreted into the intrastrial space by Na+-K+-ATPase in the basolateral membrane of them. Another, less likely possibility is that Na+ in the perilymph is transported into basal cells or fibrocytes in the spiral ligament, then into intermediate cells via gap junctions, and finally secreted into the intrastrial space via Na+-K+-ATPase of intermediate cells.

Authors+Show Affiliations

Department of Otolaryngology, Kochi Medical School, Nankoku 783-8505, Japan.No affiliation info availableNo affiliation info availableNo 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

14644454

Citation

Higashiyama, Kasumi, et al. "Bumetanide-induced Enlargement of the Intercellular Space in the Stria Vascularis Critically Depends On Na+ Transport." Hearing Research, vol. 186, no. 1-2, 2003, pp. 1-9.
Higashiyama K, Takeuchi S, Azuma H, et al. Bumetanide-induced enlargement of the intercellular space in the stria vascularis critically depends on Na+ transport. Hear Res. 2003;186(1-2):1-9.
Higashiyama, K., Takeuchi, S., Azuma, H., Sawada, S., Yamakawa, K., Kakigi, A., & Takeda, T. (2003). Bumetanide-induced enlargement of the intercellular space in the stria vascularis critically depends on Na+ transport. Hearing Research, 186(1-2), pp. 1-9.
Higashiyama K, et al. Bumetanide-induced Enlargement of the Intercellular Space in the Stria Vascularis Critically Depends On Na+ Transport. Hear Res. 2003;186(1-2):1-9. PubMed PMID: 14644454.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Bumetanide-induced enlargement of the intercellular space in the stria vascularis critically depends on Na+ transport. AU - Higashiyama,Kasumi, AU - Takeuchi,Shunji, AU - Azuma,Hiroshi, AU - Sawada,Shoichi, AU - Yamakawa,Kazuhiro, AU - Kakigi,Akinobu, AU - Takeda,Taizo, PY - 2003/12/4/pubmed PY - 2004/9/17/medline PY - 2003/12/4/entrez SP - 1 EP - 9 JF - Hearing research JO - Hear. Res. VL - 186 IS - 1-2 N2 - The intercellular space in the stria vascularis (intrastrial space) is a closed space and isolated from both the endolymph and the perilymph in normal tissue. Loop diuretics such as bumetanide and furosemide cause an acute enlargement of the intrastrial space in association with a decline in the endocochlear potential. It is known that bumetanide inhibits the Na+-K+-2Cl- cotransporter, which is expressed abundantly in the basolateral membrane of marginal cells. We studied ionic mechanisms underlying the bumetanide-induced enlargement of the intrastrial space using perilymphatic perfusion in guinea pigs. Perilymphatic perfusion with artificial perilymph containing 100 microM bumetanide caused marked enlargement of the intrastrial space, as reported previously. Removal of K+ from the perilymph did not affect the bumetanide-induced enlargement, whereas removal of Na+ from the perilymph inhibited it almost completely. Perilymph containing 1 mM amiloride also inhibited the enlargement of the intrastrial space almost completely. These results indicate that perilymphatic Na+, but not K+, and amiloride-sensitive pathways are essential to the bumetanide-induced enlargement of the intrastrial space. Two possible pathways could yield these results. Na+ in the perilymph could enter the endolymph via Reissner's membrane or the basilar membrane; Na+ in the endolymph would then be taken up by marginal cells via the apical membrane and secreted into the intrastrial space by Na+-K+-ATPase in the basolateral membrane of them. Another, less likely possibility is that Na+ in the perilymph is transported into basal cells or fibrocytes in the spiral ligament, then into intermediate cells via gap junctions, and finally secreted into the intrastrial space via Na+-K+-ATPase of intermediate cells. SN - 0378-5955 UR - https://www.unboundmedicine.com/medline/citation/14644454/Bumetanide_induced_enlargement_of_the_intercellular_space_in_the_stria_vascularis_critically_depends_on_Na+_transport_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0378595503002260 DB - PRIME DP - Unbound Medicine ER -