9319693 Nowycky Neurons and endocrine cells release chemical messengers to communicate with other cells. The triggering signals for release begin with the entry of calcium from the extracellular environment. Calcium ions appear to act on many proteins in a coordinated fashion for the release process to occur. In this grant proposal, we will use real- time measurements of release from single cells to study the intracellular responses to calcium entry which are necessary for release.***