Activity-induced PAK phosphorylation is not blocked by adenosine. (A) Deconvolution images show total PAK3 ir (left) and the colocalization of pPAK1/2/3 and PSD95 (right panels) in proximal CA1 str. radiatum. The arrows indicate a double-labeled element. (B) Quantification (mean ± SEM) of pPAK⁺ PSDs shows that adenosine (Ado) significantly increased the numbers of pPAK⁺ PSDs (n = 7–11; *, P < 0.05 vs. control). TBS followed by adenosine 30 s later increased pPAK⁺ PSDs above values in adenosine alone slices (n = 11; ***, P < 0.001 vs. control; ##, P < 0.01 vs. adenosine). (C) Results from B presented as the difference between TBS + treatment and treatment alone group values (TBSΔ; mean ± SEM). (D) Western blots from slices treated with adenosine or vehicle (veh) for 5 min (same slices as in Fig. 3 C). (E) Plots show raw band ODs (left) or the same measure normalized to β-actin (right; means ± SEM; *, P = 0.02). The latter measure exposed an adenosine-induced increase in levels of pPAK. Bars: (A [left]) 10 µm; (A [right]) 5 µm.