Figure 1.

Ca²⁺ sparklets in a heterologous expression system. (A) Ca²⁺ current evoked by a depolarization from −70 to +20 mV in a representative nontransfected (control) cell and cell expressing Cavα1.2. (B) Image of a cell transfected with Cavα1.2 only. The traces below the images show the time course of [Ca²⁺]_i in the sites marked by the green circle before and after the application of 500 nM Bay-K 8644. (C) Amplitude histogram of Ca²⁺ sparklets in tsA-201 cells expressing Cavα1.2 before and after Bay-K 8644 treatment. The black and red lines are the best fit to the control (q = 37 nM) and Bay-K 8644 (q = 37 nM) data, respectively, with the multicomponent Gaussian function described in the Materials and Methods section. (D) Bar plot of the mean ± SEM of the nP_s before and after Bay-K 8644 application.