Figure 3.
Voltage independence of kinetic parameters. (A) Open probability is shown as a function of voltage for three patches individually. Values differed between patches, due to different intracellular Ca2+ concentrations (▴, ♦, 1 μM; ▪, 0.8 μM) and different types of channel behavior (high and low open probability behavior, see later), but for all patches open probability was essentially voltage independent. The line was drawn for display purposes only and has no physical meaning. (B) Average short and long open times for the patches in A. Data are shown as mean ± SD, and the lines represent the best fit of the data to single exponential functions. (C) Relative amplitude of the short open-time component as a function of voltage shown individually for each patch in A. The line was drawn for display purposes only. Data from each patch are represented by the same symbol in A, C, E, and F. (D) Short and intermediate closed times for the patches in A. Data are shown as mean ± SD and the lines represent the best fit of the data to exponential functions. (E) Long closed times shown for two patches individually and fit to a single exponential (solid lines). In the patch with the highest open probability, too few events were associated with the longest time constant to reliably fit this component. (F) Relative amplitudes of the short (closed symbols) and intermediate (open symbols) closed-time components plotted individually for the patches in A.