Figure 2. Release probability and number of release sites are different at the calyx synapse.

A,B, variance–mean analysis of individual cells shows difference in quantal parameters between the endbulb and calyx synapse (initial slope of parabola proportional to quantal amplitude; curvature of parabola related to release probability and number of release sites). C, summary data showing that quantal amplitude is significantly smaller at the calyx synapse. Release probability (probability of releasing at least one vesicle from a release site), and number of release sites (N) are significantly greater at the calyx versus the endbulb synapse. (Endbulb data in C from Oleskevich & Walmsley, 2002.) *Significant difference (P < 0.05) from normal animals. Error bars are s.e.m.