Phorbol esters enhance transmitter release in rat hippocampal slices

Phorbol esters enhance synaptic transmission in the rat hippocampal slice preparation most likely by acting at a presynaptic locus. To more directly examine the actions of phorbol esters on neurotransmitter release we have measured their effects on the occurrence of spontaneous postsynaptic potentials as well as on the potassium stimulated release of endogenous glutamate. Both measures of transmitter release were increased by phorbol esters suggesting a functional or regulatory role for protein kinase C in controlling the release of neurotransmitter in the mammalian CNS.