Figure 1. DRG neurons exhibit variable levels of native GCaMP3 fluorescence.
Paraformaldehyde-fixed sections of GCaMP3-expressing DRG. (A) Endogenous GCaMP3 signal demonstrated a wide range of resting GCaMP3 fluorescence. Arrow indicates cell with a small somata and high resting GCaMP3 signal. Arrowhead indicates somata with low GCaMP3 signal. Asterisk indicates cell with large somata and no GCaMP3 signal. (B) The same section as in (A) but stained with anti-GFP antibody to boost GCaMP3 signal. Now, somata with low or no endogenous GCaMP3 signal can be seen to express the transgenic GCaMP3 protein. (C) Merged images. Scale bar, 50 µm.