Presynaptic modification of synaptic transmission at identified Aplysia central synapses, induced by changes in protein kinase C activity.

The effect of altered protein kinase C (PKC) activity level on the synaptic transmission in the central ganglia of Aplysia californica was studied. EPSPs or EPSCs evoked in the postsynaptic neuron by presynaptic nerve stimulation were recorded while the ganglion was in vitro treated with PKC activators (phorbol diacetate and SC-10) or PKC blockers (H-7, sphingosine, Cremophor-EL). It was found that the postsynaptic reaction was enhanced by increased and reduced by decreased PKC activity and that this modulatory influence of PKC was presynaptic.