Hippocampal mossy fiber synaptic transmission and its modulation.

Signal transmission between the dentate gyrus and hippocampal CA3 region is mediated by the mossy fibers (MFs), the axons of dentate granule cells. The MF- CA3 synaptic transmission is regulated by various neurotransmitters and neuromodulators. Since single MF inputs activated in bursts can generate postsynaptic action potentials and play an instructive role in associative synaptic plasticity at CA3 recurrent excitatory synapses, modulations of this input are supposed to have a substantial impact on activity of the hippocampal neuronal network. Intrinsic properties of the MF synapse and its modulatory system can be changed by environment and experience. Some of these extrinsic influences on the MF synapse may be mediated by hormones. The modulatory system at the MF synapse could also be a potential target for pharmacological treatments of psychiatric disorders. Here I review some of characteristic properties of the MF synapse and its modulatory system.