A novel cone visual cycle in the cone-dominated retina.

The visual processing of humans is primarily reliant upon the sensitivity of cone photoreceptors to light during daylight conditions. This underscores the importance of understanding how cone photoreceptors maintain the ability to detect light. The vertebrate retina consists of a combination of both rod and cone photoreceptors.

ARPE-19 cell growth and cell functions in euglycemic culture media.

Human retinal pigmented epithelial cells (ARPE-19) grown in euglycemic media (5.5 mM) had lower cell number, significantly different cell morphology, and lower levels of vascular endothelial growth factor (VEGF) in the culture media than those grown in hyperglycemic media (18 mM) customarily used for culturing ARPE-19 cells. Although it has been shown that within a 24-hour period, all-trans retinoic acid significantly reduces VEGF secretion by retinal pigmented epithelial cells (grown in 18 mM glucose), such an inhibitory effect was not observed in cells grown in 5.

11-cis-Acyl-CoA:retinol O-acyltransferase activity in the primary culture of chicken Muller cells.

A novel retinoid cycle has recently been identified in the cone-dominated chicken retina, and this cone cycle accumulates 11-cis-retinyl esters upon light adaptation. The purpose of this study is to investigate how 11-cis-retinyl esters are formed in the retina. Primary cultures of chicken Muller cells and cell membrane were incubated with all-trans- or 11-cis-retinol to study retinyl ester synthesis.

Effect of light exposure on the accumulation and depletion of retinyl ester in the chicken retina.

A previous study has shown that in the cone-rich chicken retina, 11-cis retinyl ester increases with light exposure and decreases in subsequent dark adaptation. The purpose of this research is to study how light exposure (intensity and duration) determine the rate of accumulation and utilization as well as the size of this 11-cis retinyl ester pool in the chicken retina. Chickens were dark-adapted overnight before exposure to different light intensities and durations.

Retinoid cycles in the cone-dominated chicken retina.

In past decades, the role of retinoids in support of rod photopigment regeneration has been extensively characterized. In the rhodopsin cycle, retinal chromophore from bleached rod pigments is reduced to retinol and transferred to the retinal pigment epithelium (RPE) to store as all-trans retinyl ester. This ester pool is subsequently utilized for visual pigment regeneration.