PROTEIN-KINASE-C IN SYNAPTIC PLASTICITY - CHANGES IN THE IN-SITU PHOSPHORYLATION STATE OF IDENTIFIED PRESYNAPTIC AND POSTSYNAPTIC SUBSTRATES

1. Long-term potentiation and its counterpart long-term depression are two forms of activity dependent synaptic plasticity, in which protein kinases and protein phosphatases are essential. 2. B-50/GAP-43 and RC 3/neurogranin are two defined neuronal PKC substrates with different s ynaptic localization. B-50/GAP-43 is a presynaptic protein and RC3/neu rogranin is only found at the postsynaptic site. Measuring their phosp horylation state in hippocampal slices, allows us to simultaniously mo nitor changes in pre- and postsynaptic PKC mediated phosphorylation. 3 . Induction of LTP in the CAI field of the hippocampus is accompanied with an increase in the in situ phosphorylation of both B-50/GAP-43 an d RC3/neurogranin, during narrow, partially overlapping, time windows. 4 Pharmacological data show that mGluR stimulation results in an incr ease in the in situ phosphorylation of B-50/GAP-43 and RC3/neurogranin .