Résumé
We show that gadolinium (Gd
3+) is a potent calcium channel blocker in guinea-pig isolated ventricular myocytes. A dose-dependent inhibition of
I
Cal
was found with an EC
50 of 1.4 μM and a complete inhibition at 10 μM Gd
3+. When compared with Cd
2+, it appeared that the blockade of
I
Cal
is a complex phenomenon probably involving more than one site of interaction (a Hill coefficient of 1.6 was found for Gd
3+ vs. 1.0 for Cd
2+). It is concluded that Gd
3+ ions completely block
I
Cal
at concentrations used to block stretch-activated channels (SAC), rendering its use as a specific SAC inhibitor problematic.