EFFECTS OF PKA AND PKC ON MINIATURE EXCITATORY POSTSYNAPTIC CURRENTS IN CA1 PYRAMIDAL CELLS

Protein kinases play an important role in controlling synaptic strengt h at excitatory synapses on CA1 pyramidal cells. We examined the effec ts of activating cAMP-dependent protein kinase or protein kinase C (PK C) on the frequency and amplitude of miniature excitatory postsynaptic currents (mEPSCs) with perforated patch recording techniques. Both fo rskolin and phorbol-12,13-dibutryate (PDBu) caused a large increase in mEPSC frequency, but only PDBu increased mEPSC amplitude, an effect t hat was not observed when standard whole cell recording was performed. These results support biochemical observations indicating that PKC, s imilar to calcium/calmodulin-dependent protein kinase II, has an impor tant role in controlling synaptic strength via modulation of AMPA rece ptor function, potentially through the direct phosphorylation of the G luR1 subunit.