Figure 7.

Propagated glial Ca²⁺ waves evoke vasodilation and vasoconstriction in distant arterioles. A–D, Fluorescence images showing an ATP-evoked Ca²⁺ wave propagating through glial cells at the vitreal surface of the retina. Dilation occurs when the Ca²⁺ wave reaches the vessel. The site of focal ATP ejection, used to initiate the Ca²⁺ wave, was just beyond the top right corner of the images. Scale bar, 20 μm. E, Time course of Ca²⁺ increase and vessel dilation in A–D, measured at the arrowheads in the images. Arrows in E indicate the time of acquisition of images A–D. F, Vessel dilation after arrival of glial Ca²⁺ waves is reduced by the epoxygenase inhibitor PPOH (20 μm) but not by preincubation in TeNT. L-NAME (100 μm) or DPI (3 μm) is present in superfusate. G, H, Fluorescence images before and after the arrival of a glial Ca²⁺ wave. Vasoconstriction occurs after the arrival of the Ca²⁺ wave. The vessel is filled with fluorescein. Scale bar, 20 μm. I, Time course of Ca²⁺ increase and vessel constriction after initiation (arrow) of a Ca²⁺ wave.