Figure 8. Intracellular Ca²⁺ measurements in isolated NMRI mouse colonic crypts.

A, Fluo-4 fluorescence (original recording) measured in crypt base region (red) and mid-crypt region (black). Adrenaline (5 μm) did not increase [Ca²⁺]_i. In contrast, 100 μm ATP increased [Ca²⁺]_i especially in the crypt base region. Inset: a single Fluo-4 loaded crypt displayed in pseudo-colour. The crypt base measured region of interest is marked in red and the crypt mid-region in black. B, summary of the relative increase of Fluo-4 fluorescence as a function of agonist addition (n= 8). The short horizontal bars indicate mean values and the * a significant [Ca²⁺]_i increase.