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Ca(2+) regulation of endocochlear potential in marginal cells.
J Physiol Sci. 2009 Sep; 59(5):355-65.JP

Abstract

We examined the effect of the cytosolic Ca(2+) concentration ([Ca(2+)](c)) in marginal cells on the asphyxia- or furosemide-induced decrease in the endocochlear potential (EP) by perfusing the endolymph with or without a Ca(2+) chelator or inhibitors of Ca(2+)-permeable channels or Ca(2+)-pump during transient asphyxia or intravenous administration of furosemide. We obtained the following results. (1) Endolymphatic administration of SKF96365 (an inhibitor of TRPC and L-type Ca(2+) channels) or EGTA-acetoxymethyl ester (EGTA-AM) significantly inhibited both the transient asphyxia-induced decrease in EP (TAID) and the furosemide-induced decrease in EP (FUID). (2) Endolymphatic perfusion with nifedipine significantly inhibited the TAID but not the FUID. (3) The recovery from the FUID was significantly suppressed by perfusing the endolymph with EGTA-AM, nifedipine, or SKF96365. (4) Endolymphatic administration of thapsigargin inhibited both the FUID and TAID. (5) The recovery rate from the FUID was much slower than that from the TAID, indicating that furosemide may inhibit the Ca(2+)-pump. (6) A strong reaction in immunohistochemical staining for TRPC channels was observed in the luminal and basolateral membranes of marginal cells. (7) A positive staining reaction for the gamma subunit of epithelial Na(+) channels was observed in the luminal and basolateral membranes of marginal cells. (8) Positive EP was diminished toward 0 mV by the endolymphatic perfusion with 10 muM amiloride or 10 muM phenamil. Taken together, these findings suggest that [Ca(2+)](c) regulated by endoplasmic Ca(2+)-pump and Ca(2+)-permeable channels in marginal cells may regulate the positive EP, which is partly produced by the diffusion potential of Na(+) across the basolateral membrane in marginal cells.

Authors+Show Affiliations

Department of Physiology II, Osaka Medical College, 2-7 Daigakumachi, Takatsuki, Osaka, 569-8686, Japan.No affiliation info availableNo 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

19504169

Citation

Mori, Yoshiaki, et al. "Ca(2+) Regulation of Endocochlear Potential in Marginal Cells." The Journal of Physiological Sciences : JPS, vol. 59, no. 5, 2009, pp. 355-65.
Mori Y, Watanabe M, Inui T, et al. Ca(2+) regulation of endocochlear potential in marginal cells. J Physiol Sci. 2009;59(5):355-65.
Mori, Y., Watanabe, M., Inui, T., Nimura, Y., Araki, M., Miyamoto, M., Takenaka, H., & Kubota, T. (2009). Ca(2+) regulation of endocochlear potential in marginal cells. The Journal of Physiological Sciences : JPS, 59(5), 355-65. https://doi.org/10.1007/s12576-009-0043-9
Mori Y, et al. Ca(2+) Regulation of Endocochlear Potential in Marginal Cells. J Physiol Sci. 2009;59(5):355-65. PubMed PMID: 19504169.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Ca(2+) regulation of endocochlear potential in marginal cells. AU - Mori,Yoshiaki, AU - Watanabe,Masahito, AU - Inui,Takaki, AU - Nimura,Yoshitsugu, AU - Araki,Michitoshi, AU - Miyamoto,Manabu, AU - Takenaka,Hiroshi, AU - Kubota,Takahiro, Y1 - 2009/06/06/ PY - 2008/11/10/received PY - 2009/05/02/accepted PY - 2009/6/9/entrez PY - 2009/6/9/pubmed PY - 2009/11/18/medline SP - 355 EP - 65 JF - The journal of physiological sciences : JPS JO - J Physiol Sci VL - 59 IS - 5 N2 - We examined the effect of the cytosolic Ca(2+) concentration ([Ca(2+)](c)) in marginal cells on the asphyxia- or furosemide-induced decrease in the endocochlear potential (EP) by perfusing the endolymph with or without a Ca(2+) chelator or inhibitors of Ca(2+)-permeable channels or Ca(2+)-pump during transient asphyxia or intravenous administration of furosemide. We obtained the following results. (1) Endolymphatic administration of SKF96365 (an inhibitor of TRPC and L-type Ca(2+) channels) or EGTA-acetoxymethyl ester (EGTA-AM) significantly inhibited both the transient asphyxia-induced decrease in EP (TAID) and the furosemide-induced decrease in EP (FUID). (2) Endolymphatic perfusion with nifedipine significantly inhibited the TAID but not the FUID. (3) The recovery from the FUID was significantly suppressed by perfusing the endolymph with EGTA-AM, nifedipine, or SKF96365. (4) Endolymphatic administration of thapsigargin inhibited both the FUID and TAID. (5) The recovery rate from the FUID was much slower than that from the TAID, indicating that furosemide may inhibit the Ca(2+)-pump. (6) A strong reaction in immunohistochemical staining for TRPC channels was observed in the luminal and basolateral membranes of marginal cells. (7) A positive staining reaction for the gamma subunit of epithelial Na(+) channels was observed in the luminal and basolateral membranes of marginal cells. (8) Positive EP was diminished toward 0 mV by the endolymphatic perfusion with 10 muM amiloride or 10 muM phenamil. Taken together, these findings suggest that [Ca(2+)](c) regulated by endoplasmic Ca(2+)-pump and Ca(2+)-permeable channels in marginal cells may regulate the positive EP, which is partly produced by the diffusion potential of Na(+) across the basolateral membrane in marginal cells. SN - 1880-6546 UR - https://www.unboundmedicine.com/medline/citation/19504169/Ca_2+__regulation_of_endocochlear_potential_in_marginal_cells_ L2 - https://doi.org/10.1007/s12576-009-0043-9 DB - PRIME DP - Unbound Medicine ER -