Effect of InsP3 concentration on the distribution of
Ca2+ signal amplitudes with a 25 closely packed channel
cluster. A stochastic simulation was performed under the same
conditions as for Fig. 3A (d = 12
nm), but with InsP3 concentrations equal to 0.35, 0.5,
0.65, and 1 μM in A, B,
C, and D, respectively.