Calcium, an important substance for cell activity, is relatively abundant outside cells, but is kept at low level inside cells. In nerve cells, the movement of calcium into the cell triggers a number of important processes. The most well known of these calcium-regulated processes is the release of neurotransmitters, chemical messengers which allow nerve cells to communicate with other nerve cells or to control muscle activity. However, calcium entry may also play a role in the growth of nerve cells, and may activate the types of long lasting changes in cell properties thought to underlie learning and memory. Because of its many important roles, calcium entry into the nerve cell is tightly regulated. The goal of this research is to characterize a novel mechanism for regulating calcium into nerve cells. This mechanism differs in important ways from previously described mechanisms of calcium entry, because it could allow calcium to enter nerve cells in the absence of nerve activity. The study will investigate the possible role of this calcium entry mechanism in regulating the outgrowth of axons and dendrites, extensions from the nerve cell body. A knowledge of this growth process is important in understanding normal and abnormal brain development and nerve regeneration following trauma.
