Fig. 4. Decay in Ca²⁺ transient is slower in acc muscles during relaxation. (A) Schematic summary of the experimental procedures. Calcium Green 1 dextran is injected into 1- to 4-cell stage embryos. At 24 hpf embryos are pinned on a dish and mosaically fluorescent muscle cells are observed by line-scanning with a confocal microscope during spontaneous coiling. (B) There is no difference in the timing of the increase in fluorescence during Ca²⁺ transients between wild-type siblings (black) and acc (red) embryos, but the decay of fluorescence is much slower in mutant embryos. Small and large arrowheads indicate the peak and half decay of fluorescence, respectively. (C) Quantification of the difference in time to half decay from peak fluorescence. Ca²⁺ decay is slower in acc muscles than in wild-type siblings.