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

First published online October 5, 2006
Journal of Experimental Biology 209, 4033-4039 (2006)
Published by The Company of Biologists 2006
doi: 10.1242/jeb.02470

This Article Summary 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 Google Scholar Google Scholar Articles by Chatelier, A. Articles by Bois, P. Search for Related Content PubMed PubMed Citation Articles by Chatelier, A. Articles by Bois, P.

Effects of oleic acid on the high threshold barium current in seabass Dicentrarchus labrax ventricular myocytes

A. Chatelier^1,*, N. Imbert¹, J. L. Zambonino Infante², D. J. McKenzie³ and P. Bois⁴

¹ Université de La Rochelle, Laboratoire de Biologie et Environnement Marin, Avenue Michel Crépeau, 17042, La Rochelle cedex, France
² Unité mixte INRA IFREMER de nutrition des poissons, BP 70, 29280 Plouzané, France
³ Department of Marine Ecology and Aquaculture, Danish Institute for Fisheries Research, North Sea Centre, DK-9850 Hirtshals, Denmark
⁴ Institut de Physiologie et Biologie Cellulaire, CNRS UMR 6187, Université de Poitiers, 86022 Poitiers cedex, France

View larger version (23K): [in a new window]   Fig. 1. Effect of OA on the voltage-activated L-type current carried by barium in sea bass ventricular myocytes. (A,B) The current was elicited by a step in membrane potential to 0 mV from a holding potential of –80 mV (insert) during 300 ms (A) at 1/20 Hz. Superimposed traces show responses of a cell in control solution, after 5 min exposure to 30 µmol l–1 OA (A) and 3 µmol l–1 nifedipine (B) (capacitance=40.71 pF). (C) Time course of the inhibitory effect of OA on the peak IBa,L. Peak currents were normalised to their initial peak current recorded at t=0 min of perfusion and are expressed as mean ± s.e.m. Black crosses, control perfusion without OA (N=11); green squares, yellow triangles, red diamonds and blue circles, OA concentrations of 5 (N=3), 10 (N=4), 30 (N=10) and 100 µmol l–1 (N=6), respectively. Significant differences between control and the different OA concentrations are indicated (*P<0.05, **P<0.01). (D) Concentration dependence of inhibition by OA on IBa,L after 5 min of perfusion. The number of cells treated with OA at 5, 10, 30 and 100 µmol l–1 is 3, 4, 10 and 6, respectively. The line was obtained by fitting data to the Hill equation (see Materials and methods), which gave an IC50 of 12.49±0.27 µmol l–1 and a Hill factor of 1.97±0.07. Values are mean ± s.e.m. Dissimilar letters indicated a significant difference (P<0.05) of IBa,L diminution between the different OA concentrations.

View larger version (14K): [in a new window]   Fig. 2. Effect of OA on density–voltage and conductance–voltage relationships. (A) Current density–voltage relationships were plotted for the L-type inward current of sea bass ventricular myocytes in controls (black crosses; N=11 between –60 to +30) and in the presence of 30 µmol l–1 OA (red diamonds; N=9 between –60 to +30). For +40 mV N=9 and N=7 in control and OA conditions, respectively. (B) Conductance curves constructed from the density–voltage curves in A. Values are mean ± s.e.m. Significant differences between control and the different OA concentrations are indicated (*P<0.05, **P<0.01).

View larger version (11K): [in a new window]   Fig. 3. Steady-state activation (A) and inactivation (B) curves of calcium channels in control and after 5 min of perfusion with 30 µmol l–1 OA. Current amplitude were normalised to maximum current and plotted against holding potential. Data were fit using the appropriate form of the Boltzmann equation (see Materials and methods). Individual ventricular myocytes used for inactivation and activation curves were respectively three and 11 for control and four and nine for 30 µmol l–1 OA.