Presynaptic Glutamate Receptors in the Hippocampus

Summary

To study the mechanisms of presynaptic modulation, a novel optical method to detect presynaptic Ca²⁺ influx in slice preparations was developed and has been adopted in the study of the presynaptic glutamate receptors in hippocampal CA1 synapse. Two classes of glutamate receptors, i.e., metabotropic glutamate receptors (mGluR) and kainate receptors (KA-R), were shown to have the presynaptic inhibitory actions in the CA1 synapse, and it has been demonstrated that inhibition of presynaptic Ca²⁺ influx plays a major role in mGluR and KA-R-mediated inhibition of transmitter release. Because these glutamate ‘autoreceptors’ can regulate the glutamate release in a feedback manner, activity-dependent as well as pathological activation of these receptors might be important for hippocampal functions.