Mechanically induced calcium waves. (A) Measurements of calcium waves in connective glia. A probe coming from the left approaches a Calcium Green 1–injected glial cell. Blue squares are 25-µm² regions of measurement at 20-µm intervals beginning at the site of initiation. (B) An example of a mechanically induced calcium wave in a glial cell. Glial cells were filled with Calcium Green 1 and stimulated with a piezoelectric controlled tungsten probe (refer to Materials and methods). ΔF/F was determined for six 25-µm² regions located as shown with squares; the baseline F was fixed. The wave properties of the calcium response were evaluated by the increased delay of the calcium response with distance from the site of stimulation.