Imaging and analysis of evoked excitatory-postsynaptic-calcium-transients by individual presynaptic-boutons of cultured Aplysia sensorimotor synapse

Using live imaging of the postsynaptic [Ca2+]i while monitoring the EPSP, we found that evoked transmitter release generates excitatory postsynaptic calcium concentration transients (EPSCaTs) by two mechanisms: (a) activation of DNQX-sensitive postsynaptic receptors-gated calcium influx and (b) calcium influx through nitrendipine-sensitive voltage-gated calcium channels (VGCCs). Concomitant confocal imaging of presynaptic boutons and EPSCaTs revealed that approximately 86% of the presynaptic boutons are associated with functional synapses.