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Calcium transport mechanism in the endolymph of the chinchilla.
Hear Res. 1988 Aug; 34(3):307-11.HR

Abstract

The Ca2+ transport mechanism between endolymph and perilymph was evaluated by the effects of vanadate and amiloride on the endocochlear potential (EP) and the Ca2+ concentration in endolymph using Ca2+-selective microelectrodes. Under normal conditions, the EP was 81.8 +/- 0.9 mV, and the Ca2+ concentrations in endolymph and perilymph were 16.6 +/- 1.3 microM and 1.85 +/- 0.11 mM (N = 12), respectively. Therefore, the uphill electrochemical potential gradient for Ca2+ from perilymph to endolymph, 20.2 +/- 2.0 mV, indicates the existence of an active uptake of Ca2+ into endolymph. Vanadate, the inhibitor of Ca2+-ATPase, topically applied to the round window membrane caused biphasic changes of the EP and the endolymph Ca2+ concentration; the former in a transient increase followed by a consistent decrease and the latter in a slow decrease followed by a slow increase. Amiloride induced a slight EP depression and a concomitantly slight elevation of the Ca2+ concentration in endolymph. The electrochemical potential gradient for Ca2+ between endolymph and perilymph vanished with the use of vanadate but was not affected by amiloride. These results suggest that Ca2+-ATPase, sensitive to vanadate, maintained the bulk of active Ca2+ transport in the cochlea and that the participation of Na+-Ca2+ exchange is negligible.

Authors+Show Affiliations

Department of Otolaryngology, University of Minnesota, Minneapolis 55414.No affiliation info available

Pub Type(s)

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

Language

eng

PubMed ID

2971641

Citation

Ikeda, K, and T Morizono. "Calcium Transport Mechanism in the Endolymph of the Chinchilla." Hearing Research, vol. 34, no. 3, 1988, pp. 307-11.
Ikeda K, Morizono T. Calcium transport mechanism in the endolymph of the chinchilla. Hear Res. 1988;34(3):307-11.
Ikeda, K., & Morizono, T. (1988). Calcium transport mechanism in the endolymph of the chinchilla. Hearing Research, 34(3), 307-11.
Ikeda K, Morizono T. Calcium Transport Mechanism in the Endolymph of the Chinchilla. Hear Res. 1988;34(3):307-11. PubMed PMID: 2971641.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Calcium transport mechanism in the endolymph of the chinchilla. AU - Ikeda,K, AU - Morizono,T, PY - 1988/8/1/pubmed PY - 1988/8/1/medline PY - 1988/8/1/entrez SP - 307 EP - 11 JF - Hearing research JO - Hear. Res. VL - 34 IS - 3 N2 - The Ca2+ transport mechanism between endolymph and perilymph was evaluated by the effects of vanadate and amiloride on the endocochlear potential (EP) and the Ca2+ concentration in endolymph using Ca2+-selective microelectrodes. Under normal conditions, the EP was 81.8 +/- 0.9 mV, and the Ca2+ concentrations in endolymph and perilymph were 16.6 +/- 1.3 microM and 1.85 +/- 0.11 mM (N = 12), respectively. Therefore, the uphill electrochemical potential gradient for Ca2+ from perilymph to endolymph, 20.2 +/- 2.0 mV, indicates the existence of an active uptake of Ca2+ into endolymph. Vanadate, the inhibitor of Ca2+-ATPase, topically applied to the round window membrane caused biphasic changes of the EP and the endolymph Ca2+ concentration; the former in a transient increase followed by a consistent decrease and the latter in a slow decrease followed by a slow increase. Amiloride induced a slight EP depression and a concomitantly slight elevation of the Ca2+ concentration in endolymph. The electrochemical potential gradient for Ca2+ between endolymph and perilymph vanished with the use of vanadate but was not affected by amiloride. These results suggest that Ca2+-ATPase, sensitive to vanadate, maintained the bulk of active Ca2+ transport in the cochlea and that the participation of Na+-Ca2+ exchange is negligible. SN - 0378-5955 UR - https://www.unboundmedicine.com/medline/citation/2971641/Calcium_transport_mechanism_in_the_endolymph_of_the_chinchilla_ L2 - https://linkinghub.elsevier.com/retrieve/pii/0378-5955(88)90010-X DB - PRIME DP - Unbound Medicine ER -