A kinetic model of control on secretion in neuroendocrine cells

Transmitter release is the fundamental mechanism for chemical communication between cells. The releasing of secretory vesicle contents into extracellular space has several kinetic steps, and each step is controlled by free intracellular calcium concentration [Ca/sup 2+/]/sub i/. The releasable vesicles pool has two parts, immediately releasable pool (IRP) and readily releasable pool (RRP), which are respectively distributed within about 30 nm and 300 nm from Ca/sup 2+/ channels. We use membrane capacitance measurement technique to monitor secretory activity, and determine the size of secretory vesicle pools. A corresponding model of secretion can simulate the dynamics of vesicles pools with the control of [Ca/sup 2+/]/sub i/.