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Electrophysiological Recordings of Bovine Chromaffin Cells: The Relationship between Calcium Current and Kinetics of Endocytosis.


Yan Sun Photo

James Madison High School (Virginia)

Abstract

Exocytosis and endocytosis are fundamental processes of biological systems. Neurons and neuroendocrine cells such as chromaffin cells transmit information through a mechanism known as exocytosis, where vesicles containing neurotransmitters or peptides are released. Vesicle release is triggered by calcium (Ca2+ ) influx through voltage-gated Ca2+ channels. After exocytosis, vesicle membrane and proteins are retrieved through endocytosis. Previous studies have indicated that Ca2+ plays a critical role in regulating both exocytosis and endocytosis. The role of Ca2+ in triggering and regulating exocytosis has been studied intensely. However, little is known about the relationship between Ca2+ and endocytosis.  Here, I assessed if there is a relationship between depolarization-induced rise in Ca2+ current and 1) magnitude of exocytosis; and 2) kinetics of endocytosis. In order to do that I used whole-cell voltage clamp recordings in bovine chromaffin cells.  The data show as the Ca2+ current increases, the magnitude of exocytosis increases and the rate of endocytosis also increases. Thus, this study indicates that Ca2+ current regulates both exo- and endocytosis.

Last updated November 27, 2013