QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Payan, P. Articles by Mayer-Gostan, N. Search for Related Content PubMed PubMed Citation Articles by Payan, P. Articles by Mayer-Gostan, N. Social Bookmarking                         What's this?

The Journal of Experimental Biology 205, 2687-2695 (2002)
© 2002 The Company of Biologists Limited

Otolith growth in trout Oncorhynchus mykiss: supply of Ca²⁺ and Sr²⁺ to the saccular endolymph

P. Payan^1,*, G. Borelli¹, F. Priouzeau¹, H. De Pontual², G. Buf³ and N. Mayer-Gostan¹

¹ Laboratoire R.O.S.E. (Réponses des Organismes aux Stress Environnementaux), UMR 1112, INRA-UNSA, Université de Nice-Sophia Antipolis, Faculté des Sciences, Parc Valrose, 06108 Nice Cedex 2, France
² IFREMER, DRV, RH, Laboratoire de Sclérochronologie des Animaux Aquatiques, BP 70, 29280 Plouzane, France
³ Observatoire Océanologique, Laboratoire Arago, Université de Pierre et Marie Curie, CNRS 639, BP 44, 66651, Banyuls sur Mer Cedex, France

^* Author for correspondence (e-mail: payan{at}unice.fr)

Accepted 15 May 2002

Kinetic and pharmacological characteristics of Ca²⁺ fluxes across the saccular epithelium of trout were studied using a perfused isolated inner ear. ⁴⁵Ca²⁺ influx from the Ringer solution to the endolymph was 3-4 nmoles h^-1µl^-1 endolymph, which corresponds to a global turnover rate of the endolymph calcium of 200 % h^-1. Ca²⁺ entry into the proximal endolymph was faster than into the distal fluid. Net Ca²⁺ movement across the saccular epithelium depended on the direction and intensity of the chemical gradient of calcium between the Ringer solution and the endolymph. Increasing the calcium concentration in the Ringer solution up to 4.4 mmol l^-1 provoked an accumulation of Ca²⁺ in both proximal and distal endolymphs, and equilibrium was reached about 30 min after the beginning of perfusion. Perfusion with calcium-free Ringer partially emptied the proximal compartment of calcium, whereas the calcium levels in the distal endolymph did not vary during 70 min of perfusion. Verapamil (10^-5 mol l^-1) and cyanide (CN, 10^-3 mol l^-1) did not modify the accumulation of Ca²⁺ within the endolymph in the presence of a favourable calcium chemical gradient. Furthermore the relationship between Ca²⁺ net fluxes and the chemical calcium gradient across the saccular epithelium was linear, indicating a passive diffusional mechanism via a paracellular pathway. Similar relationships were found for Sr²⁺ fluxes across the saccular epithelium in the presence of positive chemical gradients (1, 2 and 4 mmol l^-1 Sr²⁺). In vivo experiments in which trout were intraperitoneously injected with CaCl₂ solution confirmed the tight relationship between the calcium levels in plasma and endolymph (both proximal and distal). Sampling proximal and distal endolymphs in trout and turbot saccules revealed a decreasing proximo—distal calcium gradient in endolymph of both fish species. The present results strongly suggest that the endolymph is supplied with Ca²⁺ and Sr²⁺ via a paracellular pathway located in the proximal area of the saccular epithelium.

Key words: trout, Oncorhynchus mykiss, calcium, flux, endolymph, otolith, perfusion, inner ear

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter    What's this?

This article has been cited by other articles:

				S. Cruz, J.-C. Shiao, B.-K. Liao, C.-J. Huang, and P.-P. Hwang Plasma membrane calcium ATPase required for semicircular canal formation and otolith growth in the zebrafish inner ear J. Exp. Biol., March 1, 2009; 212(5): 639 - 647. [Abstract] [Full Text] [PDF]

				J.-C. Shiao, S.-M. Wu, Y.-P. Hwang, D.-P. Wu, and P.-P. Hwang Evaluation of thyroid-mediated otolith growth of larval and juvenile tilapia J. Exp. Biol., June 15, 2008; 211(12): 1919 - 1926. [Abstract] [Full Text] [PDF]

				S. Melancon, B. J. Fryer, J. E. Gagnon, and S. A. Ludsin Mineralogical approaches to the study of biomineralization in fish otoliths Mineralogical Magazine, April 1, 2008; 72(2): 627 - 637. [Abstract] [Full Text] [PDF]

				G. A. Manley, U. Sienknecht, and C. Koppl Calcium Modulates the Frequency and Amplitude of Spontaneous Otoacoustic Emissions in the Bobtail Skink J Neurophysiol, November 1, 2004; 92(5): 2685 - 2693. [Abstract] [Full Text] [PDF]

				G. Borelli, M. E. Guibbolini, N. Mayer-Gostan, F. Priouzeau, H. De Pontual, D. Allemand, S. Puverel, E. Tambutte, and P. Payan Daily variations of endolymph composition: relationship with the otolith calcification process in trout J. Exp. Biol., August 1, 2003; 206(15): 2685 - 2692. [Abstract] [Full Text] [PDF]