Figure 7.

A PKA target, but not a non-PKA target, is hyperphosphorylated in astrocyte-poor cultures. A, MAP2, GABA, and phospho-CREB (PKA phosphorylation site) immunoreactivity in neurons on multicell islands from astrocyte-rich or astrocyte-poor cultures. Summary pCREB immunoreactivity values are given in the Results. Scale bar, 20 μm. B, Left, Phospho-dynamin 1 (PKC phosphorylation site) immunoreactivity in autaptic neurons from astrocyte-rich and astrocyte-poor cultures. Scale bar, 20 μm. Right, Quantification of background-subtracted phospho-dynamin 1 intensity from a single primary and two secondary dendrites averaged per neuron. As a positive control, we treated for 30 min with phorbol ester (1 μm PDBu), which increased PKC-dependent phosphorylation of dynamin 1 (n = 30 neurons; *p < 0.05, Bonferroni corrected).