Figure 1

Effect of low Ca²⁺ on mouse rod flash responses recorded with LERG-OS. (a) Response families first recorded in normal Ca²⁺ (black traces and left y-axis) and then in low Ca²⁺ solution (red traces and right y-axis). The flash strengths were 2.64, 10.5, 41.9, 167, and 664 R*rod⁻¹ in both solutions and responses are averages from 1 to 7 repetitions. (b) Operation curves for rod flash responses recorded in normal Ca²⁺ (black squares) and in low Ca²⁺ (red circles) solution normalized with the LERG-OS saturation amplitude. Each symbol presents mean value from 9 experiments. The first symbol from left illustrates a calculated average single-photon response (dim flash response divided with the stimulus strength). (c) Pepperberg plot where the time points of saturated response return to 75% level (T_75%) are plotted against the natural logarithm of the flash strength. The dominant time constant of the saturated response return is determined as a linear fit to data. Symbols present mean values from 7 to 10 experiments. In both (b) and (c) responses were always recorded first in normal and then in low Ca²⁺ solutions. The error bars present SEMs.