Figure 1.

SEER imaging of mag-indo-1 inside the sealed t system of a rat skinned fibre A, image of fluorescence F₁ (acquired as defined in Methods); B, image F₂; C, R =F₁/F₂, spatially restricted to the two upper quartiles of the dye distribution (Launikonis et al. 2005). Fibre was bathed in low Mg²⁺. Image-averaged R was 1.82, corresponding to a [Ca²⁺]_t-sys of 0.28 mm. Average dye concentration in the well-stained region was 12.2 μm. (ID: 101805c_#11.)