par Couturier, Etienne 
;Malaisse, Willy
Référence IRCS Medical Science, 8, page (72)
Publication Publié, 1980
;Malaisse, Willy Référence IRCS Medical Science, 8, page (72)
Publication Publié, 1980
Article révisé par les pairs
| Résumé : | The transport of calcium across the plasma membrane of living cells and the phenomenon of ionophore-mediated calcium translocation across a hydrophobic domain display several analogies. The present work extends this series of analogies to the effect of cobalt, which is currently used as a selective blocker of the late calcium channels in excitable cells. The results indicate that cobalt is a potent inhibitor of A23187-mediated calcium translocation into a hydrophobic domain. Other cations, such as magnesium and barium also inhibit calcium translocation, apparently by competing with calcium for common reactive sites in the ionophoretic molecule. Cobalt may act in a comparable manner. The affinity constant of A23187 for divalent cations is reported to be 3 orders of magnitude higher with cobalt (3.5 x 10-4) than calcium (3.7 x 10-7). The latter value is in good agreement with the data here found in the absence of cobalt (approximately 2 x 10-7). In conclusion, cobalt may affect calcium handling in living cells, in part at least, by interfering with calcium transport by native ionophoretic systems. |
