Chapter 5 Control of time course of glutamatergic synaptic currents

Abstract

Publisher Summary The duration of the synaptic current is a key element in determining the overall function of glutamatergic synapses. The duration of the postsynaptic response is of importance in determining the consequence of repetitive synaptic activity. Temporal summation—a fundamental component in the integration of synaptic signals—is prominent when excitatory postsynaptic potentials are long enough to overlap. Conversely, precise neural coincidence detection requires the minimization of temporal summation so that only near-simultaneous, narrow synaptic events are able to drive a cell to action potential threshold. In addition to mediating electrical computation, glutamatergic synaptic events drive long-term changes in the biochemical state of postsynaptic cells. Studies in the past years have identified many of the major parameters that influence the duration of the synaptic current. These include synaptic geometry, receptor-binding affinity and channel gating kinetics, glutamate transporters, and quantal release kinetics. Synaptic transmission mediated by glutamate and glutamate receptors draws upon a wide variety of factors to determine the duration of the synaptic current. Because these factors can be varied independently, glutamate synapses can, with appropriate parallel variation in postsynaptic cable properties, be specialized for integration, coincidence detection, or the passive relay of signals.