Fig. 7.

Timing of glutamate release and receptor activation. A, Receptor activation is terminated very rapidly. Curves showing when synaptic AMPA (solid line) and NMDA (dashed line) receptors are activated, defined as binding a second glutamate molecule (see Results). The curves represent the cumulative fraction of all activations (up to 50 msec) occurring after instantaneous release of a single vesicle.B, C, Slow glutamate release reduces AMPA responses and delays NMDA responses. Families of synaptic AMPA (B) and NMDA (C) receptor responses to the instantaneous release of a vesicle (“0”) or to release of the contents of one vesicle at a uniform rate over 0.1, 0.3, 1, 3 or 10 msec (timing indicated above each panel).