LOCALIZATION OF RETINALDEHYDE ISOMERASE IN THE CHICKEN INNER RETINA

DÍAZ NM; MORERA L P; GUIDO ME.

Córdoba

Jornada; V Jornadas de posgrado; 2011

UNC

Retinal cone and rod photoreceptor cells (PRC) are responsible for day and night vision respectively while the inner retina has been mainly involved in the transmission of the nerve impulse from PRC to the brain. However, a third group of PRC has been shown recently to be present in the inner retina, specially in intrinsically photosensitive retinal ganglion cells (reviewed in Guido et al., 2010). Moreover, different non-visual opsins such as Opn4 , Opn5 and RGR were shown to be expressed in the inner retina. However, it is still unknown the mechanism used to regenerate the photopigment chromophore. RPE65 is the main isomerohydrolase in the vertebrate eye expressed in the retinal pigment epithelium but not in the neural retina.The zebra fish has three different isoforms for the RPE65 enzyme of which, RPE65c is expressed in the retina. In the chicken, we observed the expression of the RPE65c homolog in the inner retina only, especially in the inner nuclear and inner plexiform layers. Using specific cell markers we found that expression was mainly restricted to amacrine cells. In addition, we found isomerohydrolase activity in this retinal area. In conclusion, chicken amacrine cells display the expression and activity of this non-typical isomerase. Results provide first evidences on the mechanism by which the inner retina may regenerate the chromophore linked to non-visual opsins.