Figure 6.

PKA-dependent hyperphosphorylation of synapsin is normalized by thrombospondin. A, Phospho-synapsin (PKA phosphorylation site) immunostaining in DIV 10–12 autaptic neurons from astrocyte-rich or astrocyte-poor cultures with or without 5 μg/ml TSP treatment at DIV 7. Red circles are representative regions of interest defined by vGluT-1 immunoreactivity (data not shown). Scale bar, 5 μm. B, Summary of background-subtracted phospho-synapsin at vGluT-1-positive synapses in DIV 10–12 autaptic neurons (n = 35 neurons; *p < 0.05, Bonferroni corrected). C, Synapsin immunostaining at vGluT-1-defined synapses (red circles are representative) in autaptic neurons from astrocyte-rich or astrocyte-poor cultures. Summary immunoreactivity values are given in the Results. Scale bar, 5 μm.