Fig. 3. Ca²⁺ transients are smaller in ryr mutant fast muscles. (A) Schematic summary of the experimental procedure. Calcium Green-1 dextran was injected into one cell of 8- to 16-cell-stage embryos. Embryos (48 hpf) were pinned on a dish and given mechanosensory stimulation by a puff of liquid to the tail. The relative level of Calcium Green-1 fluorescence (F/F) in muscle fibers was assayed by line-scanning with a confocal microscopy. (B) The transient increase in relative fluorescence represents the transient increase of Ca²⁺ in the fast muscle following stimulation (arrow) of a wild-type embryo (black) and that of an ryr mutant (red). (C) The transient increase of Ca²⁺ in slow muscle is unperturbed in ryr mutants (red) compared to wild-type (black).