RUI: Pigment Granule Dispersion in Teleost Retinal Pigment Epithelium: Cholinergic Mechanisms

Texas State University - San Marcos, San Marcos TX

Investigators

Abstract

The proposed research looks at what happens when light hits the eye. Research will examine what happens when the eye adjusts to changing light levels and how that information is transmitted between the retina and the retinal pigment epithelium (RPE). It will zero in on tiny chemical messengers used by the retina to communicate with the RPE. The RPE is a thin layer of tissue located next to the retina. The researchers will use fish eyes as a source of tissue for these studies. Unlike human eyes, fish eyes have pupils of fixed diameter. Fish don't adjust to changing light by dilating or constricting their pupils the way people do. Instead they rearrange their light-sensitive photoreceptors and the pigment granules in the RPE to get just the right amount of light to the photoreceptors, rods or cones, best suited for the job. In the light, pigment granules in the RPE spread out into finger-like extensions that interlace with the rods and cones. These rearrangements let the RPE shade the rod photoreceptors, which are specialized for night vision, while still permitting the cone photoreceptors, bright light and color vision specialists, to detect light. This study will examine the receptors through which acetylcholine, one of the tiny chemical messengers, operates. Receptors are like little antennae found on the surface of cells, and they detect specific chemicals in their environment. There are many different types of receptors for acetylcholine. Each detects acetylcholine, but each has a different effect on molecular signals inside the cell. This study will use chemicals that either mimic or block acetylcholine to figure out what type of receptor is involved in pigment dispersion. This research will illuminate a novel signaling pathway for light adaptation, enhancing understanding of how the eye works.