Molecular and Cellular Neuroscience Commons^™

The Role Of Parkin In Mitochondrial Dna, Eliezer Lichter

Theses & Dissertations

Mitochondria are at the center of biological phenomena such as aging and diseases, especially neurodegenerative diseases. While the discovery of mitochondria only came approximately 200 years after the cell was discovered, a lot of progress has been made since. The mitochondrial genome encodes proteins vital for mitochondrial function. These proteins are only a subset of the proteins present in mitochondria; the rest are nuclear encoded. The nucleus also encodes cytosolic proteins vital for mitochondrial maintenance. One of these is Parkin, an E3 ubiquitin ligase that ubiquitinates mitochondrial proteins as mitochondria become depolarized. Its activity has been shown to be involved …

Mechanisms Of Calcium-Dependent Neurotransmission In Photoreceptors, Justin J. Grassmeyer

Theses & Dissertations

Rod and cone photoreceptors initiate vision by transforming light into graded membrane voltage changes that in turn dictate the rate of continuous Ca²⁺-dependent neurotransmission to postsynaptic neurons. Continuous release relies on synaptic ribbons at photoreceptor active zones, which organize exocytotic proteins and deliver vesicles to release sites near voltage-gated Ca²⁺ channels. Individual cones possess multiple ribbon synapses at which they contact postsynaptic neurons. We examined heterogeneity in signaling at individual ribbon synapses in salamander cones by measuring the voltage dependence of Ca²⁺ currents (I_Ca) and Ca²⁺ influx at individual ribbon release sites. Ca …

Characteristics Of Exocytosis And Endocytosis In Photoreceptors, Karlene M. Cork

Theses & Dissertations

Photoreceptors signal changes in light intensity to downstream retinal neurons through the exocytosis of glutamate-containing synaptic vesicles. The maintenance of the vesicle exocytosis and endocytosis process is essential for ongoing synaptic signaling. This study investigated the properties of exocytosis and endocytosis in photoreceptors and their role in ongoing neurotransmission.

I used electrophysiology and imaging techniques to study the properties of vesicle exocytosis and endocytosis in photoreceptors. First, we examined baseline release in photoreceptors that occurs in the absence of depolarizing stimulation. We measured mEPSCs in whole cell patch clamp recordings from horizontal cells. After inhibiting Ca²⁺ influx and efflux …