Embryonic stem-cell derived neurones express a maturation dependent pattern of voltage-gated calcium channels and calcium-binding proteins.

There are remarkable changes of calcium binding proteins and voltage dependent Ca(2+) channel subtypes during in vitro differentiation of embryonic stem cell derived neurons. To observe these maturation dependent changes neurones were studied using combined immunohistochemical, patch clamp and videomicroscopic time lapse techniques. Embryonic stem cell derived neuronal maturation proceeds from apolar to bi- and multipolar neurones, expressing all Ca(2+) channel subtypes. There is, however, a clear shift in channel contribution to whole cell current from apolar neurones with mainly N- and L-type channel contribution in favour of P/Q- and R-type participation in bi- and multipolar cells. Expression of the calcium binding protein parvalbumin could be detected in bipolar, while calretinin and calbindin was preferentially found in multipolar neurones. Our data provides new insights into fundamental neurodevelopmental mechanisms related to Ca(2+) homeostasis, and clarifies contradictory reports on the development of Ca(2+) channel expression using primary cultures of neurones already committed to certain brain compartments.