Fig. 7: Reciprocal changes in lumen volume of secretory and excretory ducts.

a Time series of a representative plane of an eccrine gland stained with CMDR showing the secretory duct (SD), in which the lumen is pseudocolored in green. Different parts of the excretory ducts (ED1 and ED2) are boxed in magenta and blue. b Procedural steps to extract the lumen areas as signal voids from an X-Y plane using Imaris software. The time-lapse 3D data in (a) were decomposed into multiple planes (X-Y) at different depths. Each plane was processed as follows: First, CMDR signals were rendered (“X-Y plane”) and digitally masked (“Masking”), followed by removal of the masked area from the rendered X-Y image (“Removal”). The lumen area was determined as unmasked remnants (“Lumen”). The X-Y panels with the extracted lumen areas were Z-stacked to reconstruct the luminal space for volume measurements (“Z-stack” and “3D”). Time series of perspective views of the Z-reconstructed luminal space in the secretory duct (c), ED1 (d) and ED2 (e) with and without the CMDR-stained cellular framework. The yellow dotted lines indicate the outline of the duct. The white arrows in c indicate the direction of compression. f Time course of the changes in the lumen volume in the secretory duct (green) and ED1 and ED2 (blue and magenta, respectively). The following symbols denote the sequential contraction/expansion phases in the secretory duct: first contraction (*), expansion (Δ), and second contraction (◊). ▲ indicates the rapid expansion phase in ED1 and ED2. The temporal resolution is 40 seconds.