Figure 1
Schematic of the transport system used to apply direct current stimulation (DCS) to endothelial monolayers. Transwell filters containing the endothelial monolayer were sealed inside the chamber. The flux of a fluorescently tagged solute was measured through a fiberoptic cable coupled to a photon counting detector. Excitation light was provided by a laser connected to a second fiberoptic cable placed at 45° angle to the first (not shown). Water flux was measured via the automated bubble tracker, after the application of a 10 cm H2O hydrostatic pressure differential (ΔP). Endothelial monolayers were stimulated with 0.1–1.5 mA current for 10 minutes using a transcranial Direct Current Stimulator. Changes in water and solute flux across the monolayer were monitored during stimulation. TOP LEFT: bEnd.3 monolayer grown on Transwell filter and immunostained for the tight junction protein ZO-1. TOP RIGHT: Endothelial cell-cell junction model. (A) Three-dimensional sketch of the junction between two endothelial cells. The central orifice of height 2B and width WB is the break in the tight junction (TJ) strand. The TJ has a narrow slit of height 2bs and width WTJ which allows current but not fluid flow. Volume flows in the z direction, from the lumen to the tissue side, as hydrostatic (ΔP) and electrical (ΔV) forces are applied. (B) Orthogonal view of yz plane. Note that the break in the TJ is not shown in this view. (C) Orthogonal view of yx plane.
