Figure 5.

Determination of the dominant time constant from the dependence of blue-sensitive cone response duration on supersaturating flash intensity. (A and B) Superimposed suction pipette current recordings of the responses from two representative blue-sensitive cones. (A) Flashes delivered to a blue-sensitive cone in Ringer’s solution. (B) Flashes delivered to another blue-sensitive cone in 0Ca²⁺/0Na⁺ solution without correction for the junction current. In both cases, the intensity of the 436-nm flashes increased from 7.3 × 10⁴ to 6.1 × 10⁶ photons µm⁻². Each trace is the mean of two responses. (C) Mean data for the dependence of response duration on flash intensity in Ringer’s solution (protocol as in A; open circles; 11 cells) and 0Ca²⁺/0Na⁺ solution measured after junction current correction (protocol as in B; closed circles; six cells). Error bars denote SEM. Regression lines of slopes 0.39 ± 0.04 s (Ringer’s solution) and 0.80 ± 0.15 s (0Ca²⁺/0Na⁺ solution) were fitted by a weighted least-squares algorithm.