Electrophysiological response of endothelial cells to fluid-imposed shear stress

The purpose of this investigation was (i) to develop a technique for recording intracellular potentials of cultured monolayers of bovine endothelial cells using an impalement method and (ii) to apply the technique to record the intracellular potentials of endothelial cell samples that were exposed, for specific durations of time, to various levels of shear stress. Endothelial cell samples were exposed to six levels of shear stress (15, 30, 45, 60, 75 and 90 dynes/cm^2) using a parallel plate flow chamber, for periods of 5 hours and 25 hours. During exposure to shear stress, the cell samples were viewed continuously and their morphometric changes were recorded on a time-lapse video recorder. A morphometric analysis was performed using a Videoplan image analyser. It was found that endothelial cells aligned with the flow field at all levels of shear stress, and the cells became more elongated with increased shear stress. The intracellular potential recordings were obtained from two regions of the cells (cytoplasm and nucleus) using glass microelectrodes. It was found that after exposure to shear stress, the magnitude of the intracellular potentials increased with the level of shear stress and duration of exposure.