FIGURE 8.

Cytotoxic effect of atRAL in light-induced photoreceptor degeneration occurs through a signaling cascade implicating GPCRs, PLC/IP₃/Ca²⁺ signaling, and NADPH oxidase. Increased functionality of G_q-coupled GPCRs is involved in mediating atRAL toxicity during light-induced photoreceptor degeneration; however, the mechanism remains to be clarified (black arrow with dotted line). Activation of G_q-coupled GPCRs causes activation of PLC/IP₃/Ca²⁺ signaling, which in turn leads to NADPH oxidase-mediated ROS production and photoreceptor degeneration (black arrows). Pharmacological interventions targeting G_q-coupled GPCRs, PLC/IP₃/Ca²⁺, and NADPH oxidase protect the photoreceptor from light-induced, atRAL-mediated degeneration (red bars).