Thesis (Ph. D.)--West Virginia University, 2006. / Title from document title page. Document formatted into pages; contains vi, 156 p. : ill. (some col.). Includes abstract. Includes bibliographical references.

During the development of the nervous system, neurons migrate to their final location and extend neurites that navigate long distances in the extracellular environment to reach their synaptic targets. The proper functioning of the nervous system depends on correct connectivity, and mistakes in the wiring of the nervous system lead to brain abnormalities and mental illness. Growth cones are motile structures located at the tip of extending neurites that sense and respond to guidance cues encountered along the path toward their targets. Binding of these cues to receptors located on growth cone filopodia and lamellipodia triggers intracellular signaling pathways that regulate growth cone cytoskeletal dynamics. Although studies on extracellular cues and their effects on neuronal guidance are well documented, less is known about the intracellular signaling mechanisms that regulate growth cone motility. This dissertation focuses on two signaling pathways and describes how they might be involved in determining growth cone morphology during neuronal development. The specific aims of this work address: (1) the role of phosphatidylinositol-3-kinase (PI-3K) and its downstream signaling pathway in regulating growth cone motility, and (2) the effect of nitric oxide (NO) release from a single cell on growth cone morphology of neighboring neurons. This study employs defined neurons from the pond snail, Helisoma trivolvis, to demonstrate that inhibition of PI-3K induces a concomitant increase in filopodial length and a decrease in the rate at which neurites advance. These effects are mediated through the lipid and protein kinase activities of PI-3K, and filopodial elongation is due to an increase in the rate at which filopodia elongate and the time that individual filopodia spend extending. Additionally, this study demonstrates that NO release from a single cell can affect growth cone dynamics on neighboring neurons via soluble guanylyl cyclase (sGC), and that NO has a physiological effect up to a distance of 100 ìm. Overall this study provides new information on cellular mechanisms regulating growth cone motility, and suggests a potential role of PI-3K and NO in neuronal pathfinding in vivo.

Thesis (Ph. D.)--University of Washington, 2001. / Vita. Includes bibliographical references (leaves 102-114).

Thesis (Ph. D.)--University of Oklahoma. / Bibliography: leaves 120-130.

Thesis (Ph. D.)--University of Washington, 2002. / Vita. Includes bibliographical references (leaves 77-87).

Univ., Diss., 2006--Frankfurt (Main)

Thesis (Ph. D.)--University of Washington, 2007. / Vita. Includes bibliographical references (p. 73-82).

Thesis (Ph.D.). / Written for the Dept. of Biochemistry. Title from title page of PDF (viewed 2009/06/09). Includes bibliographical references.

Thesis (Ph.D.)--Medical College of Ohio, 2005. / "In partial fulfillment of the requirements for the degree of Doctor of Philosophy in Medical Sciences." Major advisor: William Maltese. Includes abstract. Document formatted into pages: iv, 134 p. Title from title page of PDF document. Bibliography: pages 107-132.

Thesis (Ph. D.)--University of Washington, 2004. / Vita. Includes bibliographical references (leaves 94-116).