Physiology Commons^™

Synaptotagmin C2b Ca2+-Binding Loops Impose Distinct Exocytosis Phenotypes, Michael W. Schmidtke

Wayne State University Theses

Regulated exocytosis from chromaffin cells in the adrenal medulla plays a critical role in maintaining organismal homeostasis. In the absence of stress, these cells release physiologically relevant substances into the blood stream only in limited quantities, whereas stressful conditions result in a rapid deluge of signaling molecules used, for example, to increase heart rate and pain tolerance. Although the cellular mechanisms governing the switch from low-level to stress-induced secretion are not well understood, recent evidence has implicated the exocytotic Ca2+-sensing protein Synaptotagmin (Syt) in this role.

Two isoforms of Syt are expressed in chromaffin cells (Syt-1 and Syt-7), and each …

Role Of Secretory Granule Heterogeneity In Calcium-Triggered Exocytosis, Tejeshwar Rao

Wayne State University Dissertations

The sympathetic nervous system is activated by a variety of threats to organismal homeostasis. The adrenomedullary chromaffin cell is the core effector of sympathetic activity in the peripheral nervous system. By design, the chromaffin cell secretory response is mutable so that release can be rapidly tuned to drive context-dependent changes in physiological function. However, the mechanisms by which this tuning is achieved with such high temporal fidelity and context specificity remain unclear. This represents a major gap in our understanding of the sympatho-adrenal system since it is known to modify the function of nearly every organ system in the body. …