FIGURE 3.

Unbalanced cGMP and calcium in RP. Representation of the increased levels of cGMP and Ca²⁺ in RP rods. Phototransduction cascade is shown in yellow, Ca²⁺ overload mediators are in red, Ca²⁺ clearance mediators in green. Squares highlight cellular compartments where increases of the second messenger occur. The blue arrow indicates overexpression of neuroprotective factors. Red lines indicate approaches to inhibit second messengers related cell death pathway. AIF, apoptosis-inducing factor; BAX, BCL2-associated X protein; cGMP, cyclic guanosine monophosphate; CNGC, cyclic nucleotide-gated channels; CN03, Rp-8-Br-PET-cGMPS; DHA, docosahexaenoic acid; GC, guanylate cyclase; GMP, guanosine monophosphate; IMPDH, inosine-5′-monophosphate dehydrogenase; MMF, mycophenolate mofetil; P2X7, Purinergic receptor P2X7; PDE6, phosphodiesterase 6; PEDF, pigmented epithelium-derived factor; PEDF-R, pigmented epithelium-derived factor-receptor; PKGs, cGMP-dependent protein kinases; PL, phospholipids; PMCA, plasma membrane calcium ATPase; VGCC, voltage–gated calcium channels.