Abstract
We tested a hypothesis that water ejection takes place in the secretory cell. A micro bead was held at about 1μm distant from the cell surface by laser trapping with a 1064 nm light, and the position of the bead was measured by DIC imaging with a visible light. A series of small displacements of the bead was detected transiently upon stimulation of the cell, indicating repetitive occurrences of volume flow. The water ejection from endocrine cell detected by the present technique has a significant role in the exocytotic release of hormones.
