Developmental changes of Ni2+ sensitivity and automaticity in Nkx2.5-positive cardiac precursor cells from murine embryonic stem cell

Abstract

Background: It is controversial which subtypes of T type Ca2+ channels are implicated in automaticity of cardiac cells during the embryonic period. Method and Results: The effect of Ni2+ on the automaticity of Nkx2.5-positive cardiac precursor cells sorted from embryonic stem cells during their differentiation was examined using patch clamp techniques. Although 40 μmol/L Ni2+, which is enough to block Ni2+sensitive T type-Ca2+ channels, decreased the spontaneous beating rate in all cells in the early and intermediate stage, Ni2+ did not show any effects on the automaticity of 50% of the cells in the late stage. Conclusion: These results indicate that Ni2+-sensitive T-type Ca2+ channels expressed in the Nkx2.5-positive cardiac precursor cells are developmentally regulated.