Fig. 2

Representative data showing the relationship between the beginning of the calcium transient and contraction of the rat heart primordium loaded with fluo-3 AM. A Representative ventral view of a rat embryo just removed from the uterus. This sample corresponds to the data marked with the asterisk in Fig. 3. B Dorsal view of the embryo shown in A. Asterisks indicate somites. The number of somites for this embryo is 3. C Ventral view of the embryo. The pericardium was partially removed and the caudal part of the embryo was removed. D Ventral view of the embryo. The pericardium and forebrain were almost completely removed. White arrowheads indicate the outer margin of the heart primordium. E, F Fluorescence (E) and visible light (F) images of the embryo in the small incubator. These pictures correspond to the dotted rectangle in D. G The change in rate. Open circles represent the rate calculated from the fluorescence movie and filled circles represent the rate calculated from the visible light movie. H Fluorescence recordings of the change in the calcium transient corresponding to several parts shown in E and to several times shown in G. Arrowheads indicate the peak of the calcium transient. The data in the inset panel show a longer dataset than subpanel b1. I Recordings of motion corresponding to several parts shown in F and to several shown in G. Direction of the contraction, cr (cranial), corresponds to that in F