James Madison High School (Virginia)
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