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Ophthalmology Commons

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Full-Text Articles in Ophthalmology

Multiquantal Glutamate Release From Rod Photoreceptors, Cassandra L. Hays Aug 2020

Multiquantal Glutamate Release From Rod Photoreceptors, Cassandra L. Hays

Theses & Dissertations

Neurons communicate via Ca2+-dependent release of neurotransmitters packaged into vesicles (quanta). Some CNS neurons, especially sensory synapses, can release multiple vesicles at a time, increasing information transmission and overcoming the unreliability of a stochastic process. Ribbon-bearing neurons, including retinal photoreceptors, face the challenge of encoding sensory receptor potentials into an ever-changing train of vesicle release events. We studied release of glutamate using voltage clamp to measure anion currents activated during glutamate reuptake into presynaptic terminals (IA(glu)) of salamander and mouse rods, finding that each employ distinct mechanisms for multiquantal release. In amphibian rods, we found that …


Melanopsin-Expressing Retinal Ganglion Cells In Control Vs. Glaucomatous Retinas, Edward Hamad Jan 2020

Melanopsin-Expressing Retinal Ganglion Cells In Control Vs. Glaucomatous Retinas, Edward Hamad

Williams Honors College, Honors Research Projects

Glaucoma is a common cause of vision loss worldwide and has a large scope of symptoms, ranging from pupillary reflex defects to sleep disorders. These issues can be explained partially by a recently found subtype of retinal ganglion cells that express melanopsin, denoted melanopsin-expressing retinal ganglion cells or mRGCs for short. These cells function primarily as photoreceptors in the non-image forming pathway, but can receive input from rods and cones. Since mRGCs play a role in the pupillary reflex and regulation of the sleep-wake cycle, I investigated if glaucoma leads to the degeneration of these cells in a mouse model …