Figure 3.

(A) Histogram analysis of current levels observed in 740 patches (unshaded histogram with thick outline). Also plotted (shaded histogram with thin outline) is the Poisson distribution with the same mean current level number per patch (0.44 current level/patch for 740 patches), calculated by assuming that each current level represents an individual IP₃R that exhibited only the M state and that the channels were evenly distributed on the outer nuclear membrane. (B) Histogram analysis of number of channels in the 740 patches (unshaded histogram with thick outline) assuming that all IP₃R channels observed exhibited the D state, such that every two current levels detected represents one channel. The theoretical Poisson distribution with the same mean channel number per patch (0.25 channel/patch for 740 patches) is also plotted (shaded histogram with thin outline). In both cases, the large number of observed multiple-channel patches compared with the number of observed single-channel patches suggests that the IP₃R channels are not evenly distributed in the outer nuclear membrane of oocytes.