Figure 5.

Extracellular TNBS delivery followed by TNBS microinjection quenches almost all the cell associated DHE fluorescence. TRVb1 cells were labeled with DHE-MβCD as described in the legend of Figure 2. DHE was distributed at the PM and the ERC (A). TNBS (10 mM) was added on the microscope stage, and an image of the same field was taken within 30 s (B). A concentrated stock of 100 mM TNBS, along with Rh-dextran was microinjected into a few cells of this same field and imaged immediately (C). Injected cells were identified by Rh-dextran labeling and shown by arrows. Images shown here have been background corrected using off-cell fluorescence intensity, and intensity was further corrected for photobleaching. Scale bar, 10 μm. The quenching of fluorescence in 29 cells in five microscopy fields was quantified and has been shown next to the images. Error values are SDs of quenching values.