Fig. 3.

The estimated release site Ca²⁺ during an action potential. (A) The example EPSCs before (ctl, black) and after (forskolin, red) the application of forskolin. Data represent an average of 40 to 50 traces from the same cell. (B, Top) The estimated local Ca²⁺ concentration at the transmitter release sites. (B, Bottom) Release rates from the EPSC deconvolution method. The local Ca²⁺ concentration at the release site was estimated using the release model of ref. 25. The release parameters were fixed in Figs. 1 and 2, and only free parameter is the time course of the local Ca²⁺ at the release site. The Ca²⁺ waveform was set so that the entire time course of release was simulated fully (dotted lines). (C) From Top, the average EPSC amplitudes, peak release rates, and the estimated peak local Ca²⁺ concentration under control and in the presence of forskolin are plotted. Individual and average data are plotted. The differences are statistically significant (P < 0.05, 0.05, 0.01, respectively; paired t test).