Fig. 7.

Light-induced Ca²⁺ rise in a WT photoreceptor loaded with the low-affinity indicator dyeMag-INDO-1. In response to a saturating UV stimulus, Ca²⁺ rose rapidly beyond 50 μm. Data were recorded at a holding potential of −70 mV in standard (1.5 mmCa²⁺) Ringer’s solution containing no Mg²⁺. Mg²⁺ was also omitted from the recording electrode solution. Similar results were obtained in four other cells.