Figure 2.

(A) Log-log plot of release probability vs. open channel probability (computed using Eq. 4), assuming two equidistant channels, and no saturation of release (r=2⁵=32). The value of the slope yields Ca²⁺ current cooperativity of exocytosis, m_ICa, and is different along different parts of the curve. The black curve is a regression line, the slope of which would be the experimentally determined m_ICa. (B) The dependence of both m_ICa and m_CH on p_o. Colors of points correspond to colors of line segments in (A).