FIGURE 4.

Kinetics of pH changes in an observation area on the membrane surface as a function of its distance s to the area of proton release. The maximum of fluorescence (i.e., the peak of the surface proton concentration in the observation area) appeared with a delay τ_max after proton uncaging. τ_max was a linear function of s². In this plot, the shades of gray of the circles correspond to the shade of gray of representative experimental traces recorded at s = 60, 77, 100, and 125 μm. For clarity, the experimental records corresponding to the triangles are omitted.