C-PKA dynamics in OSN. Nuclear translocation of the YFP tagged catalytic subunit of the PKA sensor: basal condition (t0), and 10 minutes and 20 minutes after (A) forskolin (25 μM) bath applied, and (B) after an odor puff, focally applied to the growth cone. (C) Control, illuminated as in A and B but without stimulation. The excitation and emission wavelengths were 500 and 545 nm, respectively. At these wavelengths, only YFP is excited and, accordingly, the fluorescence is insensitive to cAMP and only sensitive to the YFP concentration/distribution. In B, a few aggregates of PKA-C are found, as in approximately 40% of transfected OSNs.