Calcium anti-ionophoretic effect of some calcium channel blockers in rat liver mitochondria.

Beyond their classical action on calcium channels, some calcium channel blockers also exhibit a calcium anti-ionophoretic effect. We studied this effect on respiratory control and Ca2+ fluxes in a mitochondrial model to compare calcium antagonists chosen among three clinical classes: vascular, cardiac, and mixed effects. Synthetic calcium ionophore A23187 decreases respiratory control and modifies Ca2+ fluxes. We show that calcium antagonists partially restore the parameters altered by A23187. By calculating the percentage of restoration, we found that vascular drugs exhibit a strong anti-ionophoretic effect, cardiac drugs exert no significant effect, and mixed calcium antagonists exert an intermediate effect. Thus, it appears possible to link the intensity of calcium anti-ionophoretic effect with the clinical interest of a calcium antagonist.