Quantification of Synaptic Vesicles and Inner Segment Organelles in the Photoreceptors of a Simplex Vertebrate Retina
By: Seyedsahand Zahirazami, Louie Jackson, Meagan Prasad
Department: Biology
Faculty Advisor: Dr. Ivan A. Anastassov
Millions of cells in the retina, a thin tissue layer that borders the back of the eye, perform vital visual functions. Rods and cones (photoreceptors) are light-sensitive cells that efficiently detect light at varying brightness levels and send information to the brain via networks of other cells. Following decades of research, it has been determined that most retinas contain rods and cones. Rods mediate dim light function, whereas cones mediate bright light function. Furthermore, rods utilize existing cone circuitry networks rather than generating new ones. Studying the retina of Leucoraja erinacea (Little Skate) helps us understand vertebrate retinal circuitry in a pure-rod visual system since the L. erinacea retina contains only a rod.
Interestingly, the skate retina can also perform work under photopic and scotopic light. Typically, rods and cones are necessary for such a function. There are two projects that we are working on. The first is free synaptic vesicle quantification in photoreceptor terminals within the L. erinacea retina. This project allows us to compare the ultrastructural characteristics of skate rods to other vertebrate rods. The second project involves the reconstruction of photoreceptor mitochondria and comparing them qualitatively and quantitatively to the mitochondria of rods from mixed rod-cone retinas. This research aims to understand how rods in the retina of skate compare structurally and quantitatively to rods that can only function under dim light conditions in the hope of gaining insight into fundamental principles of vertebrate retinal design.