Prostaglandins E1, E2, and D2 induce dark-adaptive retinomotor movements in teleost retinal cones and RPE.

摘要: In teleosts, retinomotor movements of photoreceptors and retinal pigment epithelium are regulated both by light an endogenous circadian rhythm. Light induces cones to contract, rods elongate RPE cells disperse their granules into long apical projections; darkness opposite movements. When fish maintained in prolonged constant darkness, appropriate nonetheless occur at subjective dusk dawn. To explore the mechanisms this regulation, we have been investigating effects several extracellular messengers known be present retina on green sunfish (Lepomis cyanellus). Here report that prostaglandin E1 (PGE1) can induce characteristic dark onset (or night) isolated light-adapted retinas light; ie, PGE1 cone elongation granule aggregation. The extent PGE1-induced were dose-dependent with maximal movement occurring 250-500 nM; higher concentrations not as effective. Incubations PGE2 PGD2 also induced dark-adaptive movements, but PGF2 alpha did not. Further observations suggest prostaglandins may play a role mediating induction onset: dark-induced inhibited pretreating before culture agents which inhibit synthesis. Both indomethicin (50 microM) acetylsalicylic acid microM), two inhibitors cyclooxygenase component specific synthase, aggregation cultured retinas. Another inhibitor, ibuprofen had no effect. Together effectiveness inducing inhibition adaptive vivo dark-adapted onset.