Figure 1.

Effect on the bright flash response in a salamander UV-sensitive cone of superfusion with 0Ca²⁺/0Na⁺ solution. (A) Superimposed responses to saturating flashes in Ringer’s solution (heavy trace) and upon exposure to 0Ca²⁺/0Na⁺ solution from 1 s before the flash until progressively increasing times thereafter (light traces). Top traces represent solution change and flash command timings. Suction pipette currents include a junction current resulting from the liquid junction potential between the dissimilar solutions in pipette and bath. Each trace is the mean of two responses; measurements were bracketed symmetrically in time. The bright flash delivered 2.5 × 10⁶ photons µm⁻² at 362 nm. (B) Recovery phases of the responses from A after subtraction of the junction current obtained on the return to Ringer’s solution after a 2-s exposure to 0Ca²⁺/0Na⁺ solution at the end of the experiment. For each trace, the junction current has been offset in time to coincide with the return to Ringer’s solution. Data have been digitally low-pass filtered at 20 Hz. The heavy trace denotes the response in Ringer’s solution. (C) Dependence of response duration on the time spent in 0Ca²⁺/0Na⁺ solution after the flash. Response duration was measured as the time taken after the flash for 25% recovery of current (dashed line in B). Times of the solution changes were measured from the half-relaxation time of the junction current. Regression line of slope 0.43 was fitted using a least-squares algorithm.