Oscillatory Calcium Signaling and Secretion in Neuroendocrine Cells

University Of California-Los Angeles, Los Angeles CA

Investigators

Abstract

Hormones are released by cells of the brain in pulsatile patterns -- these patterns are important in determining the action of the hormones on their target organs. The brain cells that release hormones show spontaneous electrical activity and complex oscillatory increases in the concentration of calcium ions (Ca2+). While it is known that intracellular Ca2+ triggers hormone release, it is not known how different patterns of Ca2+ signaling in networks of cells lead to different patterns of hormone release. This study will use simultaneous electrophysiological recording, video imaging of intracellular Ca2+ , and measurements of secretion to investigate the mechanisms by which different types of cells generate and modulate the cellular signals that control hormone release. In 3 different types of neuroendocrine cells, the relationship between different patterns of oscillatory Ca2+ signaling and secretion will be characterized. The role of a membrane channel activated by the cellular messenger cyclic adenosine monophosphate (cAMP) in the generation of the oscillatory signaling underlying secretion will also be characterized. Finally, the role of cell-cell communication via gap junction channels will be quantified. In the reproductive system, pulsatile patterns of hormone release control a variety of different functions including sexual development and maturation, the maintenance of eggs in the ovary, ovulation, and pregnancy. The studies in this proposal will provide a dynamic characterization of the patterns of cellular signaling that control the release of hormones by networks of neuroendocrine cells. Dynamic data including video imaging of cellular signaling will be presented over the internet for scientific and educational purposes.