Figure 1.

Principle and time course of Ca²⁺-triggered synaptic transmission. (A) Schematic diagram of a synapse illustrating the localized influx of Ca²⁺ at the active zone (red = secreted neurotransmitters). (B) Schematic illustration of the sequence and time course of synaptic transmission as measured by simultaneous pre- and postsynaptic patch-clamp recordings at the calyx of Held synapse. Note that Ca²⁺ currents and EPSC are shown inverted. (Images are modified from Südhof 2004 and Meinrenken et al. 2003.)