Fig. 6.

Ca²⁺ depletion disrupts calcium transients. (A) No Ca²⁺ transients were observed in the neural plate of embryos incubated in low Ca²⁺ artificial sea water (ASW). Addition of Ca²⁺ to 11 mM (arrow) causes an immediate wave of fluorescence in the cells. The dark blue line indicates a non-expressing cell. (B,C) Representative embryos incubated in ASW containing either 11 mM or 0.5 mM Ca²⁺ and immunostained for the indicated markers. (D) Incubation of embryos in low Ca²⁺ ASW (0.5 mM Ca²⁺) for 3 hours (gastrula though initial tailbud stage) resulted in an absence of palp development, caused an open brain phenotype, and greatly reduced the presence of pigment and Arrestin-expressing cells in the sensory vesicle. Control embryos were incubated in normal ASW (11 mM Ca²⁺).