Reduced PKA activity in somatosensory cortex of PKARIIβ−/− mice. A, The ratio of PKA activity measured in the presence (+cAMP) and absence (basal) of cAMP is significantly reduced in P11 somatosensory cortex of PKARIIβ−/− (KO) mice compared with wild-type (WT) controls (histograms on left; *p < 0.005, t test). PKA activity was measured in tissue homogenates from somatosensory cortex using a protein kinase assay kit (Promega). PKAC protein levels are also significantly reduced in PKARIIβ−/− compared with wild-type littermate control mice (histograms on right; *p ≪ 0.01, t test). B, Example Western blots of synaptosomes prepared from P11 somatosensory cortex of PKARIIβ−/− mice and their wild-type littermate controls using anti-PKARIIβ and anti-PKAC antibodies. Actin is used to normalize the protein amount. As expected, PKARIIβ−/− mice have no PKARIIβ expression. Error bars show SEM.