Figure 1. Induction of ATP release and ecto-ATPase activity after mechanical stress in trabecular meshwork cells

ATP released by TM cells in cyclically stretched and nonstretched control cultures was measured using the luciferin-luciferase assay in presence of the ecto-ATPase inhibitors, ARL-67156 and reactive blue 2. Cyclically stretched cells released a significantly higher amount of ATP compared to the controls (p<0.05). To evaluate the potential increase of ecto-ATPase induced by cyclic mechanical stress, 10 μM ATP was added to the culture medium 30 min before stretching to allow cells to equilibrate after gentle shaking. Extracellular ATP was degraded at a significantly higher rate in the medium from stretched cell cultures compared to the medium from unstressed controls, indicating an increase in ecto-ATPase activity with mechanical stress (right). ATP concentration in the media is represented as relative light intensity units (RLU) and was generated in three independent experiments.